Class 12 Engineering Chemistry - Biomolecules

Give the D form of glycine.

Glycine is the simplest of all the amino acids in terms of molecular structure and is optically inactive due to the presence of two hydrogen on the same carbon atom. The structure of both L and D glycine are given in the figure above

Name the nitrogenous base present in sphingolipids.

Sphingolipids, like the phospholipids, are composed of a polar head group and two non polar tails. The core of sphingolipids is the long chain amino-alcohol, sphingosine.

* Sphingosine is a nitrogenous base present in sphingolipids.

What are the functions of carbohydrates?

Carbohydrates are one of the most important sources of energy for the body of many organisms, including humans. They provide about 4 kcal per gram (energy).

Write the name of deficiency diseases of Vitamin A, Vitamin $$B_1$$ , Vitamin C and Vitamin D.

Vitamin

Disease

$$A$$

Night blindness

$$B_1$$

Beri Beri

$$C$$

Scurvy

$$D$$

Rickets

Explain the amphoteric behaviour of amino acids.

Amphoteric behavior of amino acids is due to presence of both base element (-NH$$_{2}$$) and acid element (-COOH) which makes it act as both base and acid based on p$$ ^{H} $$ conditions.

Give example for four functional proteins

Functional proteins are proteins that don't have a structural function (these are called structural proteins).

Examples include: antibodies (bind to pathogens and opsonize them), enzymes (biological catalysis), motor proteins (help cells in locomotion), and receptor molecules (allow for signal transduction mechanisms).

How will you prepare glucose from cane sugar.

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Name the enzymes involved in the breakdown of nucleotides into sugars and bases?

Nucleases are enzymes involved in breakdown of nucleotides into sugars and bases.

Give the Free amino acids obtained on the hydrolysis of 'Aspartame'.

Methanol , phenylalanine and aspartic acid are the products after the hydrolysis of Aspartame
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Draw the structure of fructose for haworth projection formulae.

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Fructose $$\xrightarrow{Br_2/H_2O}$$ ?

Being a mild oxidising agent Br$$_{2}$$/H$$_{2}$$O can oxydise Aldehyde to carboxylic acid but It cannot oxidise the detonic group is fructose.

So, there will be no reaction.

Match List-I with List-II.

Glucose is a carbohydrate.

Insulin is a protein and a hormone.

DNA is neither carbohydrate nor protein.

H₂NCH₂CH₂COOH is neither carbohydrate nor protein.

What are the different ways in which glucose is oxidised to provide energy in various organism ?

$$\bullet$$ The breakdown of glucose involved into main processes:

$$\bullet$$ $$\textbf{Glycolysis:}$$ It is the process in which 6 molecules of carbon break to form two molecules of pyruvate containing 3 carbon in each.

$$\bullet$$ Further, the pyruvate molecule breaks down to form energy in different ways in various organisms:

$$\bullet$$ $$\textbf{Aerobic respiration:}$$ It is the process in which pyruvate molecules break down to form water and carbon dioxide by releasing energy.

$$\bullet$$ $$\textbf{Anaerobic respiration:}$$ It is the process in which pyruvate molecule breakdowns in the absence of oxygen which give rise to carbon dioxide, water and ethanol.

Photosynthesis of a carbohydrate in plants is given by chemical equation:
$$6C{ O }_{ 2 }+6{ H }_{ 2 }O\longrightarrow { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+6{ O }_{ 2 }$$
If you have net result as:
$$6C{ O }_{ 2 }+6{ H }_{ 2 }O\longrightarrow { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+6{ O }_{ 2 }$$
Check whether this reaction is correct or not.

No, $${O}_{2}$$ (product is from $${ H }_{ 2 }O$$ (reactant), hence $$12{ H }_{ 2 }O$$ is taken as reactant. It is confirmed by taking isotopic $${O}^{18}$$ when all $${O}^{18}$$ appear in $${O}_{2}$$.

$$6C{ O }_{ 2 }+6{ H }_{ 2 }{ O }^{ 18 }\longrightarrow { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+6{ H }_{ 2 }O+6{ { O }_{ 2 } }^{ 18 }$$

Match the compounds in column I with their characteristic(s)/test(s)/reaction(s)/reagent(s)/stereochemistry/isomer(s) given in column II. Matching can be one or more than one.

Glucose forms osazone derivative and is reducing in nature.
Fructose also forms osazone derivative and is also reducing in nature..
Lactose is a dissacharide forms osazone derivative and is reducing in nature.
Sucrose is a dissacharide and is non-reducing
Starch is a polysaccharide and is non-reducing.

Describe in words the atomic composition denoted by chemical formula $$C_{12}\, H_{22}\, O_{11}$$.

Every sugar molecule contains 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms chemically combined together.

After watching a programme on TV about the adverse effects of junk food and soft drinks on the health of school children, Sonali, a student of Class XII, discussed the issue with the school principal. The principal immediately instructed the canteen contractor to replace the fast food with the fiber and vitamins rich food like sprouts, salad, fruits etc. This decision was welcomed by the parents and the students. After reading the above passage, answer the following questions:
(a) What values are expressed by Sonali and the Principal of the school?
(b) Give two examples of water-soluble vitamins.

(a) Sonali and principal show the awareness for the junk food and its side effects, junk food can cause severe diseases as more consumption of junk food leads to obesity.

(ii) Water-soluble vitamins:-

Vitamin-B
Vitamin-C

What is pro-enzyme?

Proenzymes are inactive forms of enzymes which are activated in presence of activators.

$$\underset{(inactive)}{Pepsinogen}\overset{HCl}{\rightarrow}\underset{(active)}{Pepsin}$$

What are the products of hydrolysis of sugar?

The two products of hydrolysis of Sucrose are glucose and fructose. Hydrolysis breaks the glycosidic bond converting sucrose into glucose and fructose.

Give two example of water-soluble vitamins.

Water-soluble vitamins dissolve in water, which means these vitamins and nutrients dissolve quickly in the body. Unlike fat-soluble vitamins, water-soluble vitamins are carried to the body’s tissues, but the body cannot store them. Any excess amounts of water-soluble vitamins simply pass through the body. Because these vitamins are needed by our bodies, we need to make sure we intake these vitamins on a regular basis.

Water soluble vitamins include Vitamin C and the vitamin B complex: thiamin (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), Vitamin B6, biotin (B7), folic acid (B9), Vitamin B12. Vitamin A in its Beta-Carotene form is also water-soluble.

Shanti, a domestic helper of Mrs. Anuradha, fainted while mopping the floor. Mrs. Anuradha immediately took her to the nearby hospital where she was diagnosed to be severely 'anaemic'. The doctor prescribed an iron rich diet and multivitamins supplement to her. Mr.s Anuradha supported her financially to get the medicines. After a month, Shanti was diagnosed to be normal.
(i) What values are displayed by Mrs. Anuradha?
(ii) Name the vitamin whose deficiency causes 'pernicious anaemia'.
(iii) Give an example of a water soluble vitamin

1. High moral and humanitarian values are displayed by Mrs. Anuradha.
2. The most common cause of pernicious anemia is the loss of stomach cells that make intrinsic factor. Intrinsic factor helps the body absorb vitamin $$B_{12}$$ in the intestine. The loss of parietal cells may be due to destruction by the body's own immune system.
3. Vitamin B-complex group: thiamin (vitamin $$B_1$$),

Which component of starch is a branched polymer of $$\alpha$$-glucose and insoluble in water?

Starch has two fractions, water soluble amylose and water insoluble amylopectin
Amylose is unbranched polymer and amylopectin is branched chain polymer.
Starch has 20% amylose and 80% amylopectin.

Which of the two components of starch is water soluble?

Starch consists of two fractions amylose and amylopectin. Amylose is water soluble and amylopectin is water insoluble.

Define the following terms:
(i) Glycosidic linkage
(ii) Invert sugar
(iii) Oligo saccharides

(i) Glycosidic linkage

A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate.

(ii) Invert sugar

A mixture of equal parts of glucose and fructose resulting from the hydrolysis of sucrose. It is found naturally in fruits and honey and produced artificially for use in the food industry.

(iii) Oligo saccharides

An oligosaccharide is a saccharide polymer containing a small number (typically three to ten) of simple sugars (monosaccharides). Oligosaccharides can have many functions including cell recognition and cell binding. For example, glycolipids have an important role in the immune response.

What is a glycosidic linkage?

Carbohydrates such as glucose, fructose and sucrose are sweet in taste. But, starch has bland taste though it is a carbohydrate. How do you account for this?

Starch has no free- OH groups and it is non-sugar carbohydrate. Starch is polysaccharide. Generally, polysaccharides are non-sugar and they are tasteless and are insoluble in water.

Does our blood have proteases and nucleases?

Proteases and nucleases are the enzymes that digest proteins and nucleic acids respectively. Blood does not contain either of these enzymes, rather protease inhibitor is present in blood serum to protect blood proteins from protease action.

Give balanced equations for the following reactions:
(i) How will you convert ethyl amine to methyl amine?
(ii) What is the effect of denaturation on the structure of proteins?
(iii) Name the nitrogen base residues present in DNA.

(i) The conversion of ethyl amine to methyl amine is shown by the following reaction.
(ii) Denaturation of proteins is irreversible change and causes precipitation, shape destruction and loss of characteristic biological activity. It can be brought out by heating protein with alcohol, concentrated inorganic acids or by salts of heavy metals.
For example, when egg is boiled, it coagulates egg white. Milk is converted to curd.
(iii) Nitrogen base residues present in DNA are:
(a) Adenine (b) Guanine
(c) Thymine (d) Cytosine

(e) 5-methoxy cytosine

(a) Write the Haworth structure of sucrose.
(b) Sucrose is a non-reducing sugar. Why?

(a) The Haworth structure of sucrose is as shown.
(b) Sucrose is a non-reducing sugar as the reducing groups (carbonyl groups) of glucose and fructose are involved in glycosidic bond formation.

Explain the preparation of glucose from cane sugar.

$$\displaystyle Cane \: sugar \: (sucrose)$$ is boiled with dil $$\displaystyle HCl$$ or $$\displaystyle H_2SO_4$$. Hydrolysis gives equimolar mixture of
$$\displaystyle glucose$$ and $$\displaystyle fructose$$. The mixture is then cooled and $$\displaystyle alcohol$$ added. Insoluble $$\displaystyle glucose$$ crystallizes out first on cooling and is separated by filtration.

$$\displaystyle C_{12}H_{22}O_{11}+H_2O \xrightarrow [\Delta]{dil. \: HCl \: or \: H_2SO_4} \underset {glucose}{C_6H_{12}O_6}+\underset {fructose}{C_6H_{12}O_6}$$

a) i) Name the water insoluble component of starch.
ii) Mention one water soluble vitamin.
iii) Is Lysine an essential or non-essential amino acid?
b) Write the structure of Maltose.

a) i) Water insoluble component of starch is amylopectin.
ii) Thiamine riboflavin
iii) Lysine is an essential amino acid
b) Structure of maltose is shown in the image.

Name the steps in the manufacture of common sugar from sugarcane and explain the first step.

The steps in the manufacture of common sugar from sugarcane are as given below.
1. Juice extraction
a. Milling
b. Diffusion
2. Juice clarification (removes suspended solids ( mud, waxes, fibres) from the juice).
3. Juice evaporating ( concentrates the juice to a thick syrup)
4.Crystallisation and centrifuging (separates sugar crystals from the mother liquor)
5. Sugar drying
6. Packaging and delivery
1. Juice extraction:
a. Milling
The juice is squeezed from the cane under high pressure between heavy iron rollers.
b. Diffusion:
Sucrose is extracted from the cane with the use of imbibtion but without the squeezing by mills.

Write the functional groups present in a molecule of Glycine.

Glycine $$\displaystyle H_2N-CH_2-COOH$$ is an alpha amino acid. It contains amine $$\displaystyle -NH_2$$ and carboxylic $$\displaystyle -COOH$$ functional groups.

Classify Vitamins $$A, B, C$$ and $$D$$ depending upon their solubility in water and fat and compare them.

Vitamins B and C are water soluble. They are readily excreted in urine. They have low toxicity. They cannot be stored in body.
Vitamins A, D, E, K and P are fat soluble. They dissolve in oils and fats. They are stored in the body in liver and in tissues. They are toxic in excess amount.

Define carbohydrates. What are reducing and non-reducing sugars?

Carbohydrates: Carbohydrates are optically active polyhydroxy aldehydes or polyhydroxy ketones, or the compounds which on hydrolysis produce polyhydroxy aldehydes or polyhydroxy ketones.
Examples: Glucose, Sucrose, Fructose.
Reducing sugars: Carbohydrates whic reduce Fehling solution to red ppt. of $$Cu_2O$$ or Tollen's reagent to shinning metallic silver are called reducing sugars. All monosaccharides and oligosaccharides except sucrose are reducing sugars.
Non-reducing sugars: Carbohydrates which do not reduce Fehling solution and Tollen's reagent are called non-reducing sugars. E.g. Sucrose.

(a) What is fermentation? Give one example.
(b) Write the balanced chemical equations of the reactions taking place in the manufacture of ethyl alcohol from sugar.

(a)
Fermentation (a metabolic process) converts sugar to acids, gases, or alcohol. It is observed in yeast, bacteria, and in oxygen-starved muscle cells. An example is lactic acid fermentation.
(b)
Fermentation of sucrose with the enzyme invertase (present in yeast) gives a mixture of glucose and fructose.
$$\displaystyle \underset {\displaystyle \text { Sucrose} }{ C_{12}H_{22}O_{11}}+H_2O \xrightarrow {Invertase} \underset {\displaystyle \text {Glucose } }{ C_6H_{12}O_6}+\underset {\displaystyle \text { fructose } }{ C_6H_{12}O_6}$$
This mixture is converted to ethanol by enzyme zymase.
$$\displaystyle \underset {\displaystyle \text { Glucose or fructose} }{C_6H_{12}O_6 } \xrightarrow {Zymase} \underset {\displaystyle \text { ethanol}}{ 2C_2H_5OH} +2CO_2 $$

What are 'nucleic acids'?
Define complex lipids. Mention any 'two' functions of lipids.

'Nucleic acids' are esters of phosphoric acid with sugar. Sugar is linked to nitrogen bases. Nucleic acids are present in nucleus of every cell and transmits the inherent characters. DNA and RNA are two types of nucleic acids.

Complex lipids:
They are esters of long chain fatty acids and can be hydrolyzed. They include triglycerides (animal fats and vegetable oils), glycolipids, phospholipids and waxes.

Functions of lipids:
(1) Waxes provide vital waterproofing for body surfaces. Waxes repel water and form protective coatings on leaves, fruits, berries, animal fur and feather of bird.
(2) Prostaglandins can lower blood pressure, affect blood platelate aggregation during clotting, lower gastric secretion and stimulate uterine contractions during child birth.

Mention any one hydrolytic product of lecithin.

On the hydrolysis of lecithin unsaturated or saturated acyl are present present as residue.

Explain the functions of polysaccharides.

Polysaccharides generally perform one or two functions:-

Energy storage

Example- Starch and glycogen are highly compact polymers that are used for energy storage.

Structural support.

Example-Cellulose and chitin are linear polymers that are used for structural support in plants and animals.

Give the classification of carbohydrates with examples.

On the basis of the number of forming units, three major classes of carbohydrates can be defined:-

Monosaccharides,

Monosaccharides are the simplest carbohydrate which cannot be hydrolyzed further.

Oligosaccharides

Oligosaccharides on hydrolysis give 2-10 units of monosaccharides. They are further classified as a disaccharide, trisaccharides, etc.

Polysaccharides.

Polysaccharides on hydrolysis give a large number of monosaccharide units. Their general formula is $$(C_6H_{10}O_5)_n$$.

Sugar	Example
Monosaccharide	Glucose, Fructose, Ribose, Arabinose
Oligosaccharide	Sucrose, Trehalose, Maltose, Lactose
Polysaccharide	Starch, Cellulose, Glycogen, Chietin

State whether the following statements are true or false :
(i) The general formula of alkanes is $${C}_{n}{H}_{2n+2}$$.
(ii) Carbohydrates are body building nutrients.

i) The general formula of alkanes is $$C_nH_{2n+2}$$ is true.

ii) Carbohydrates are body building nutrients- False

Ans- Proteins are body building nutrients.

What is a coenzyme?

Coenzyme:- A coenzyme is an organic non-protein compound that binds with an enzyme to catalyze a reaction. Coenzymes are often broadly called cofactors, but they are chemically different.

Examples:-

NAD+ and NADP+
Coenzyme A
Menaquinone.

Equations of preparation of alcohol from sugar are given:
$${C}_{12}{H}_{22}{O}_{11}+{H}_{2}O\xrightarrow [ ]{ Invertase } \underset { A }{ { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } } +\underset { B }{ { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 } } $$
$${C}_{6}{H}_{12}{O}_{6}\xrightarrow [ ]{ zymase } 2{C}_{2}{H}_{5}OH+2{CO}_{2}$$
(a) Write the names of the Compounds $$A$$ and $$B$$.
(b) The alcohol obtained here is known as .............
(c) How can this alcohol be converted into reflected spirit?
(d) How can power alcohol be prepared?

(a) Glucose and fructose
(b) Wash
(c) By fractional distillation
(d) Power alcohol is prepared by mixing absolute alcohol with petrol.

Match the pairs correctly.

$$A = 3 Ar =$$ Argon is an inert gas filled in bulbs in place of air. Filament inside the bulb would react with oxygen and burn away if the bulb were filled with air. Argon stops the filament burning away because it is unreactive.

$$B = 4 C_6H_3SO_2Cl =$$ is a Hinsberg's Reagent used to test primary, secondary and tertiary amines.

$$C = 2$$ Sucrose = Sucrose is a disaccharide made from two monosaccharides glucose and fructose.

$$ D = 1 $$Starch = Starch is a Polysaccharide its molecule consists large number of molecules.

$$E = 6$$Vitamin C = Retinal is $$C_{20}H_{28}O$$

Write the properties of hormone.

Hormones are the chemical messengers involved in the signal pathway.

Properties of hormones:

Hormones are used in producing regulatory effects.
Hormones are not effective at the site of synthesis.
Each hormone is produced by a specific kind of cell.
Hormones are poured directly into the blood.

Mention the difference between amylose and amylopectin.

Amylose	Amylopectin
Unbranched	Branched
$$\alpha(1,4)$$-glycosidic linkage	$$\alpha(1,6)$$ and $$(1,4)$$ glycosidic linkage
Water insoluble	Water soluble

Write the functions of the following vitamins:
(i) Vitamin A (ii) Vitamin D
(iii) Vitamin E (iv) Vitamin K

The functions of the vitamins are given below.
(i) Vitamin A
It promotes growth.

(ii) Vitamin D
It helps the body absorb calcium. It helps build bones and keep bones strong and healthy.

(iii) Vitamin E
It is antisterlity factor. It is necessary for the fertility of the male and birth process of the female.

(iv) Vitamin K
it is indirectly necessary for normal blood coagulation. its deficiency delays the coagulation period of blood.

Cane Sugar, Glucose and Starch are Carbohydrates.
(a) Represent the structure of Glucose.
(b) Write a method to prepare Glucose from Starch. Write the chemical equation of the reaction.
(c) Suggest any two uses of Carbohydrates.

(b)
Preparation of glucose from starch:
Starch is boiled with dil sulphuric acid at 393 K under pressure. It is hydrolysed to give glucose.
$$\displaystyle (C_6H_{10}O_5)_n \text {( starch)} +nH_2O \xrightarrow [393 K, 2-3 atm]{dil H_2SO_4} nC_6H_{12}O_6 \text {( glucose )}$$

(c) Uses of Carbohydrates:
(i) They are important source of chemical energy for living organisms.
(ii) They are important constituents of supporting tissues in plants. e.g cellulose found in wood, cotton, flex etc.

Name two energy-providing nutrients.

Carbohydrates are one of the most important sources of energy for the body of many organisms, including humans. They provide about 4 kcal per gram. Fat is also one of the three main macronutrients, along with carbohydrate and protein. Compared to carbohydrate and protein, each gram of fat provides 9 kcal per gram.

Hence, the two energy-providing nutrients are carbohydates and fats.

What are vitamins? Write various kinds of vitamins?

Vitamins help to regulate chemical reactions in the body. They are protective compounds that do not provide energy. They help in proper functioning of the body and are required in very small quantities. There are various kinds of vitamins. They are: Vitamin A, Vitamin B complex, Vitamin C, Vitamin D, Vitamin E, and Vitamin K. Vitamins are not a source of energy.

Starch is __________ saccharide.

Starch is a polysaccharide.
A polysaccharide is a carbohydrate that on hydrolysis yields a large number of monosaccharide units. Thus, starch is a natural biopolymer of $$\displaystyle \alpha-D-$$glucopyranose.

What are carbohydrates?

$$\textbf{Solution:}$$

$$\bullet$$ Carbohydrates or sugars are naturally occurring organic compounds containing carbon, oxygen, and hydrogen atoms based on a general formula C_x(H₂O)_y.

$$\bullet$$ These are the energy-giving macromolecules and also structural components in some organisms like plants.

$$\bullet$$ Carbohydrates are produced by the green plants by the process of photosynthesis.

$$\bullet$$ They are classified into two categories which are simple sugars or monosaccharides and complex sugars (disaccharides, oligosaccharides, and polysaccharides).

$$\bullet$$ Monosaccharides are single-unit sugars like glucose, disaccharides have two monomers like sucrose (one glucose and one fructose monomer), oligosaccharides are the small chains of monomers like 3-6 units long, and polysaccharides are very long chains such as starch.

What is turn over number?

The number of substrate molecules changed per minute by a molecule of enzyme is called turn over number.

(a) What are enzymes ?
(b)Discuss the mechanism of enzyme action.

Enzymes are proteins that act as catalysts within living cells. Catalysts increase the rate of chemical reactions occurs without being consumed or permanently altered themselves.

The basic mechanism by which enzymes catalyze chemical reactions begins with the binding of the substrate to the active site on the enzyme. The active site is the specific region of the enzyme which combines with the substrate. Mechanism of enzyme action is well explained in terms of lock and key model of enzyme action.

The active site was thought to have a fixed structure (the lock), which exactly matched the structure of a specific substrate (the key). Thus the enzyme and substrate interact to form an enzyme-substrate complex. The substrate is converted to products that no longer fit the active site and are therefore released, liberating the enzyme.

Image result for lock and key mechanism figure

Arrange the following carbohydrates in the order of increasing complexity of chemical structures: fructose, starch, oligosaccharide, maltose, triose.

Triose has the molecular formula of C$$_3$$H$$_6$$O$$_3$$.

Fructose has the molecular formula of C$$_6$$H$$_{12}$$O$$_6$$. Maltose has the molecular formula of C$$_{12}$$H$$_{22}$$O$$_{11}$$. Oligosaccharides have the molecular formula of 3 to 10 times C$$_{12}$$H$$_{22}$$O$$_{11}$$.

Starch has the molecular formula of C$$_6$$H$$_{10}$$O$$_5$$ (n times) and it is also a polysaccharide.

Hence, the increasing order of complexity of chemical structures is triose> fructose> maltose> oligosaccharides> starch.

How are enzymes able to enhance the rate of reaction ?

For any chemical reaction to occur the reactants should possess a minimum amount of energy to proceed with the reaction and form products. This minimum energy required for the reaction to proceed is called the activation energy. Enzymes enhance the rate of the reaction by reducing the activation energy required for the reaction to proceed. As can be seen in the image; in the absence of an enzyme the activation energy required for the reaction to happen (red curve) is more than the the activation energy required for the same reaction to occur in the presence of an enzyme (grey curve)

Betaine $$C_{5}H_{11}O_{2}N$$, occurs in beet sugar molasses. It is water soluble solid that melts with decomposition at $$300^{\circ}C$$. It is unaffected by a base but reacts with hydrochloric acid to form a crystalline product $$C_{5}H_{12}O_{2}NCl$$. It can be made from glycine with methyl iodide or treatment of chloroacetic acid with trimethyl amine. Draw structure for betaine which will account for all properties given above.

Betaine $$ C_{5}H_{11}O_{2}N $$ reacts with HCl to form crystalline product.
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On the basis of 'sugar' differentiate D.N.A. and R.N.A:

D.N.A contains $$\beta$$-D-2-deoxyribose sugar. R.N.A contains $$\beta$$-D-ribose sugar.

Write down any two difference between nucleoside and nucleotide.

Parameter	Nucleoside	Nucleotide
Chemical Composition	A nucleoside consists of a nitrogenous base covalently attached to a sugar(ribose or deoxyribose)	A nucleotide consists of a nitrogenous base, sugar(ribose or deoxyribose) and one to three phosphate groups
Attachment	Nucleosides are attached to purines	Nucleotides are attached to pyrimidines
Examples	Few examples of nucleosides are adenosine, uridine, and cytidine	Examples of nucleotide include adenine monophosphate, adenine diphosphate, and adenine triphosphate

For a polymerization reaction: $$6HCHO\rightleftharpoons C_{6}H_{12}O_{6}$$ degree of association was found to be $$0.96$$. Calculate mean mass of mixture at equilibrium. Report value of mean molar mass of mixture dividing by $$50$$.

$$ 6HCHO\rightleftharpoons C_{6}H_{12}O_{6} $$

I O

$$ 1-6\alpha $$ $$ \alpha $$

Given , $$ 6\alpha=0.96 $$

$$ \alpha=0.16 $$

$$ 6HCHO\rightleftharpoons C_{6}H_{12}O_{6} $$

$$ \Rightarrow 1-0.96 $$ 0.16

0.04 0.16

$$ \Rightarrow $$ Mean mass of mixture $$ \Rightarrow\frac{(0.04)[6(1+12+1+6)]+0.16[6(12+2+16)]}{0.04+0.16} $$

$$ \Rightarrow\frac{0.04(6)[30]+ 0.16x6[30]}{0.2} $$

$$ \Rightarrow\frac{18x0.4+1.6x18}{0.2} $$

$$ =\frac{18x2}{0.2} $$=180g

The mass means =180gram

The mean molar mass= $$ =\frac{180}{50} $$=$$ =\frac{18}{5}g $$

What are the main characteristics of an enzyme?

Characteristics of an Enzyme :

1. Speed up chemical reactions.

2. They are required in minute amounts.

3. They are highly specific in their action.

4. They are affected by temperature.

5. They are affected by pH.

6. Some catalyze reversible reactions.

7. Some require coenzymes.

8. They are inhibited by inhibitors.

Define and give example of Essential amino acids :

Essential amino acids cannot be synthesized by the body and are supplied through diet.

Essential amino acids are also known as indispensable amino acids.

Their deficiency causes Kwashirkor a disease.

Examples of essential amino acids include valine, lucine, isoleucine, lysine, phenylalanine etc.

Name the enzyme which catalyses the conversion of soluble fibrinogen into insoluble fibrin.

Thrombin catalyzes the conversion of fibrinogen (soluble plasma protein) into long threads of fibrin (insoluble).

Short / Long answer type questions.
What happens to the starchy part of a meal from the time it is eaten till it is made available to body tissues?

The starchy part of a meal mostly contains carbohydrates. After such a meal is eaten it is digested. Digestion begins in the mouth, in the mouth the food mixes with the saliva. Saliva is secreted by the salivary glands of the mouth and contains the enzyme salivary amylase, which acts on the starch in food and breaks it down to maltose. In the stomach, the food gets mixed with the gastric juice and the action of amylase ceases due to the high acidity. However, some of the sucrose present in the food get hydrolyzed by the action of HCl in the stomach. The food then passes into the small intestine where it mixes with the pancreatic juice that contains the enzyme pancreatic amylase. It breaks down the remaining polysaccharides into maltose and isomaltose. Several disaccharidases secreted by the small intestine than act on these e.g: maltase breaks down maltose into two units of glucose, lactase breaks lactose into glucose and galactose and sucrase breaks down sucrose into glucose and fructose. These monosaccharides are then absorbed in the small intestine and made available to the body.

What was the discovery for which Sumner Was awarded Nobel Prize?

Sumner and Northrop along with Stanley won a Noble prize in 1946 for crystallization of enzymes.

Name one element invariably found in proteins but not in all carbohydrates and lipids.

Nitrogen is an element invariably found in proteins but not in all carbohydrates and lipids.

Differentiate between.
Enzymes and inorganic catalysts

Enzymes are specific protein molecules with complex 3-dimensional structure, whereas inorganic catalysts are small inorganic molecules, usually metal ions. Moreover, enzymes can .catalyse only specific reaction, whereas inorganic catalysts can catalyse a wide range of reactions.

A substance that accelerates a chemical reaction, but itself is unchanged when the reaction is over, is a.......... In living systems, most of these substances are proteins known as..........

A substance that accelerates a chemical reaction, but itself is unchanged when the reaction is over, is a catalyst. In living systems, most of these substances are proteins known as enzymes.

Write the general (empirical) formula for a carbohydrate.

C$$_x$$(H$$_2$$O)$$_y$$

Write only equation for the reactions for preparation of glucose from sugar and starch.

preparation of glucose from sugar:

$$ \underset {\text { Cane sugar or sucrose } }{ C_{12}H_{22}O_{11}}+H_2O \xrightarrow [\Delta]{ \text { dil HCl or }H_2SO_4} \underset {\text { Glucose } }{ C_6H_{12}O_6}+\underset {\text { Fructose } }{ C_6H_{12}O_6} $$

preparation of glucose from starch:

$$ \underset {\text { starch } }{ (C_{6}H_{10}O_{5} )_n}+nH_2O \xrightarrow [\text { 393 K,2-3 atm}]{ H_2SO_4} \underset {\text { Glucose } }{ nC_6H_{12}O_6} $$

Write a short note on heterocyclic base present in nucleic acids. (structure is not required).

Nucleic acids are the third class of biopolymers others are polysaccharides and proteins.

Two major classes of nucleic acids are:

1. deoxyribonucleic acid (DNA): carrier of genetic information

2. ribonucleic acid (RNA): an intermediate in the expression of genetic information and other diverse roles

The monomeric units for nucleic acids are nucleotides. These are made up of three structural subunits:

1. Sugar: ribose in RNA, 2-deoxyribose in DNA

2. Heterocyclic base

3. Phosphate

The heterocyclic base are derivatives of Pyrimidines and Purines. Purine moiety is present in Adenine(A) and guanine (G). Pyrimidine moiety is present in cytosine (C), thymine (T) and Uracil(U). G, T and U exist in the keto form.

Write a note on significance of carbohydrates.

Significance of carbohydrates includes:

1. They are energy stores of animals and plants.

2. They are immediate source of energy.

3. They make up most about 60-80% of dry mass of plants.

4. They are used as stored energy form like starch in plants and glycogen in animals.

5. Cellulose carbohydrates is a structural component of the cell wall of plants.

6. They act as fuel to physical body parts on daily basis.

7. They help in breakdown of fatty acids and prevent ketosis.

8. They also act as flavor and sweeteners.

Which enzymes are called molecular scissors?

Restriction endonucleases are called molecular scissors as they cleave nucleic acids (DNA) at specific points.

Preparation of soyabean milk and its comparison with the natural milk.

Materials required: Beakers, pestle, and mortar, measuring cylinder, glass-rod, tripod-stand, thermometer, muslin cloth, burner. Soya beans, buffalo milk, fresh curd, distilled water.

Procedure:-

Soak about $$100g$$ of soya beans in a sufficient amount of water for $$24$$ hours.
Take out swollen soya beans and grind them to a very fine paste with a pestle-mortar.
A clear white filtrate is soybean milk, add about $$250ml$$ of water to this paste and filter it through a muslin cloth.
Compare its taste with buffalo milk.
Take $$50 ml$$ of buffalo milk in three beakers and heat the beakers to $$300, 400,\ and\ 500^{\circ}C$$ respectively.
Add spoonful curd to each of the beakers and leave the beakers undisturbed for $$8$$ hours and curd is ready.
Similarly, take $$50ml$$ of soya bean milk in three other beakers and heat the beakers to $$300,400$$ and $$500^{\circ}C$$ respectively.
Add $$1$$ spoonful curd to each of these beakers. Leave the beakers
Take the results.

Write a short note on glycogen.

Glycogen is a polysaccharide of glucose that serves as energy storage in fungi and animals and acts as animal starch
Its structure is the same as amylopectin but has a higher number of branching.
It stores for glucose in areas such as liver brain etc.
The body breaks down glycogen into glucose and is used as instant energy.

Explain the importance of carbohydrates.

Importance of Carbohydrates

Carbohydrate is

$$1.$$ The most abundant bimolecules on earth.

$$2.$$ Produced by the conversion of more than 100 billion metric tons of $${ CO }_{ 2 }$$ and $${ H }_{ 2 }O$$ in photosynthesis.

$$3.$$ A major dietary staple and its oxidation is central in energy yielding pathway in living cell.

$$4.$$ Structural and protective elements in the cell walls of bacteria and plants and in the connective tissues of animals.

$$5.$$ Lubricate skeletal joints and participate in recognition and adhesion between cells as glycoconjugates.

Write a short note on starch:

starch or amylum is a polymeric carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants as energy storage. It is the most common carbohydrate in human diets and is contained in large amounts in staple foods like potatoes, wheat, maize (corn), rice, and cassava.

Classify Amino acids on basis of function and on basis of Nature of amino acids.

$$\rightarrow$$ The Classification on basis of nature is Nuetral acids.
$$\rightarrow$$ They have equal number of carboxylic homes than amino acids.
$$\rightarrow$$ They have more Amino than Carboxylic acids .
$$\rightarrow$$ The classification on the basis of function
Essential amino acids
$$\rightarrow$$ The Amino acids that are not synthesised by our body and can only be intaked from our diet.
Non Essential Amino Acids
$$\rightarrow$$ The amino acids that are synthesised by body and no hud for external intake are Non Essential Amino Acids.

Why Vitamin C can't be stored in our body?

Vitamin C is cannot be stored in our body because it is a water-soluble vitamin and gets excreted from the body with sweat or urine.

How do you explain the amphotoric behaviour of aminoacids.

In aqueous solution, the carboxyl group of an amino acid can lose a proton and the amino group can accept a proton to give a dipolar ion known as zwitter ion.

Therefore, in zwitterionic form, the amino acid can act both as an acid as well as a base.

970036_1062384_ans_3063f6c7a20044f79df0c35f76592d95.jpg

Why carbohydrates are important in our diet?

Carbohydrates are the body's main space of energy. In their absence, your body will use protein and fat for energy. Healthy sources of carbohydrates such as starchy foods, vegetables, fruits, legumes and lower fat diary products are also an important source of nutrients such as calcium, iron and $$B-$$vitamins.

Enzyme catalyzed reaction proceed at rates vastly higher than that of uncatalysed reactions. prove this statement by taking a proper example.

In order for a reaction to occur, reactant molecules must contain sufficient energy to cross a potential energy barrier, the activation energy.

The lower the potential energy barrier to the reaction, the more reactants have sufficient energy and, hence, the faster the reaction will occur. All catalysts, including enzymes, function by forming a transition state, with the reactants, of lower free energy than would be found in the uncatalysed reaction. Even quite modest reductions in this potential energy barrier may produce large increases in the rate of reaction.

For e.g., the activation energy for the uncatalysed breakdown of hydrogen peroxide to oxygen and water is 76 kJ M-1 whereas, in the presence of the enzyme catalase, this is reduced to 30 kJ M-1 and the rate of reaction is increased by a factor of 108, sufficient to convert a reaction time measured in years into one measured in seconds.

What are amino acids?

Amino acids are biomolecules which contain an amino $$ (-NH_2) $$ group and a carboxylic acid group $$ (-COOH) $$ at $$\alpha$$-carbon.

Prepare Dipeptide from Alanine.

The product formed when two amino acids interact is called dipeptide.

Alanine+Alanine $$ \rightarrow $$ dipeptide

1174965_1063134_ans_3a4f5e1bdf8147df8c60b4db07df1df7.png

Classify the following into monosaccharides,oligosaccharides and polysaccharides.
(1) starch, (2) glucose, (3) stachyose, (4) maltose, (5) raffinose,
(6) cellulose, (7)sucrose, (8) lactose.

$$1)$$ Monosaccharides $$-$$ glucose.

$$2)$$ Oligo Saccharides $$-$$ yield two (or) more than 2 mono saccharides on hydrolysis sucrose, lactose, raffinose, maltose,stachyose.

$$3)$$ Poly Saccharides $$-$$ yield more than 3 mono Saccharide on hydrolysis $$-$$ cellulose and starch.

What is the basic structural difference between starch and cellulose ?

$$Starch$$ is a 1-4 linkage of $$\alpha$$ glucose monomers and $$Cellulose$$ is formed by 1-4 linkage of $$\beta$$ glucose monomers.

1536297_1144437_ans_9129a4f3e7f84e03932353ae379c21a0.png

1536297_1144437_ans_9129a4f3e7f84e03932353ae379c21a0.png

What are enzymes? Name any one enzyme of our digestive system and write its function.

Enzymes are a group of catalysts functioning in biological system. They are usually proteinaceous substances produced by a living cell that catalyse biochemical reactions without themselves being changed in the process. Salivary amylase is an enzyme of our digestive system which converts starch into maltose, isomaltose and small dextrins called alpha dextrins.

Write the structure of $$\beta-D-$$ fructo furanose.

1377003_1151253_ans_21d3a2cef9cd402680676278b10135a7.png

Name the compound that does nit fit into the formula $$C_x (H_2O)_y$$, but is a carbohydrate.

$$C_x (H_2O)_y$$
rhamnose $$C_6H_{12} O_5$$

What are reducing sugars?

All those carbohydrates which contain a free aldehyde or Ketonic group and reduce Fehling's solution and Tollen's reagent are referred as a $$\text{reducing Sugar}$$. Examples of reducing sugar is galactose, glucose, glyceraldehyde, fructose, ribose, and xylose.

What is the general formula of carbohydrates?why this formula is no applicable to all the carbohydrates?

1351935_1201527_ans_21332799cc2d4fe6afec491dbccea057.jpg

name two water soluble vitamins, their sources and the diseases caused due to their deficiency in diet.

Water soluble vitamins include Vitamin $$C$$ and the vitamin $$B$$ complex: thiamin $$(B1)$$, riboflavin $$(B2)$$, niacin
$$(B3)$$, pantothenic acid $$(B5)$$, Vitamin $$B6,$$ biotin $$(B7)$$, folic acid $$(B9)$$, Vitamin $$B12$$. Vitamin $$A$$ in its Beta-
Carotene form is also water-soluble.

What are enzymes? Name an enzyme which is present in saliva and state its function.

Enzymes are bio-macromolecules, involved in catalyzing biochemical reactions or processes. They act as a biocatalyst. There are various factors that govern the working of an enzyme like temperature, pH etc

The enzyme present in saliva is Salivary amylase involved in breaking down or digestion of starch. It works most actively at the pH of 6.8

The binding of the substrate induces the enzyme to alter its shape fitting more tightly around the substrate.

Induced fit indicates a continuous change in the conformation and shape of an enzyme in response to substrate binding. This makes the enzyme catalytic which results in the lowering of the activation energy barrier causing an increase in the overall rate of the reaction. In other words, when a substrate binds to an enzyme, it will change the conformation of the enzyme. This forms a transitional intermediate which lowers the activation energy and allows the reactants to proceed towards the product at a faster rate. In the case of macromolecules (e.g. proteins), induced fit shows the changes in the shape of a macromolecule in response to a ligand binding so that the binding site of macromolecule conforms more efficiently to the shape of the ligand. The enzyme will change its shape until it is completely complementary to a substrate to activate the enzyme-substrate complex.

Can enzymes start a particular reaction? Explain your answer.

Enzymes never start any reaction but they accelerate it by lowering activation energy of the reaction.

How are vitamins classified? Name the vitamin responsible for the coagulation of blood.

Vitamins are classified based on their solubility.
Fat Soluble Vitamins are - Vitamin A, D, E, and K. Water soluble vitamins are Vitamin B complex vitamins and vitamin C.

Vitamin K is responsible for the coagulation of blood.

What are nucleic acids?

A complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Classify the following into monosaccharides and disaccharides. Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose.

Monosaccharides are galactose, fructose, ribose, 2-deoxyribose.
Disaccharides- Lactose, maltose

Write two main functions of carbohydrates in plants.

Carbohydrates are the source of energy in plants. Their two main functions are growth and metabolism.

Fill in the blanks:
Polymer of nucleotides are called ......

Nucleic acids are the biopolymers whose monomer is nucleotides. Nucleotides are made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base.So the correct answer is nucleic acid.

What is the Difference Between Purines and Pyrimidines?

Purines and pyrimidines are both organic compounds that take part in the synthesis of DNA and RNA. They are nitrogenous bases that make up the two different nucleotides in DNA and RNA.

$$\text{Purines (adenine and guanine) are two-carbon nitrogen ring bases while pyrimidines (cytosine and thymine) are}$$$$\text{one-carbon nitrogen ring bases.}$$

1847426_1721857_ans_7fdb6d6c6c954e4ca00bfa1278b11089.jpg

Fill in the blanks:
The formula $$C_{x}(H_{2}O)_{y}$$ can be assigned to $$...........$$

$$\text{The formula }C_x(H_2O)_y\text{ can be assigned to }carbohydrates$$

Give one example of each of the following
Reducing sugar, Non-reducing sugar

$$\text{Reducing sugars are sugars where the anomeric carbon has an OH group attached that can reduce other}$$ $$\text{compounds. Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot}$$ $$\text{reduce other compounds}$$

$$Reducing\ sugar:\text{-glucose}$$
$$None-reducing \ sugar:\text{ - cane sugar (sucrose)}$$

Name the sources of following vitamins: Vitamin D

$$\text{Vitamin D is Synthesised in skin cells in sunlight, found in butter, liver egg yolk, fish oil, etc.}$$

Classifying the following into monosaccharides, disacharides and polysaccharides
Ribose,glycogen,maltose,deoxyribose,lactose,fructose,glucose,cane-sugar ,starch cellulose

Monosaccharides also called a simple sugar, are the simplest form of sugar and the most basic units of carbohydrates. They cannot be further hydrolyzed into simpler chemical compounds.
A disaccharide (also called a double sugar) is the sugar formed when two monosaccharides (simple sugars) are joined by glycosidic linkage. Like monosaccharides, disaccharides are soluble in water. Three common examples are sucrose, lactose, and maltose.
Polysaccharides are the most abundant carbohydrate found in food. They are long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water using amylase enzymes at catalyst, which produces constituent sugars.

$$Monosaccharides:\text{ Ribose,deoxyribose,glucose,fructose}$$

$$Disaccharides:\text{ Maltose, lactose, cane sugar}$$

$$polysaccharide:\text{ Glycogen, starch cellulose}$$

Starch is a polymer of ...while cellulose that of ...

$$\text{Starch is formed from }\alpha -glucose,\text{ while cellulose is made of }\beta- glucose.$$ The difference in the linkages lends to differences in 3-D structure and function. Starch can be straight or branched and is used as energy storage for plants because it can form compact structures and is easily broken down.
1814010_1722229_ans_d013cbaafed44cba9eb1ce53eb193bca.jpg

1814010_1722229_ans_d013cbaafed44cba9eb1ce53eb193bca.jpg

Explain the observed $${K}_{b}$$ order:
$$E{t}_{2}NH> E{t}_{3}N> Et{NH}_{2}$$ in aqueous solution

Due to combination of +I effect, solvation effect and steric hindrance of ethyl group the basic strength of ethyl substituted amines in aqueous solution is as follows:
$$E{t}_{2}NH> E{t}_{3}N> Et{NH}_{2}$$
As a stronger base has a higher $${K}_{b}$$ value, therefore, $${K}_{b}$$ value decreases in the order:
$$E{t}_{2}NH> E{t}_{3}N> Et{NH}_{2}$$

Which monosaccharide units are present in starch, cellulose, and glucose, and which linkage link these units?

In starch and glycogen, glycosidic $$\alpha$$ linkage is present. Cellulose is a straight-chain polysaccharide composed only of $$\beta$$ -D- glucose units which are joined by the glycosidic linkage between $$C_1$$ of one glucose unit and $$C_4$$ of the next glucose unit.

What are polysaccharides ? Give on example?

Polysaccharides are the carbohydrates which on hydrolysis give a large number of molecules of monosaccharides.

For example, starch or cellulose.

Unscramble the following word related to components of food.

BOCATRADHYER

The correct word is carbohydrate.
1986918_1787330_ans_36376e1e8c9142abaa65680d13852889.jpg

What is the basic structural difference between starch and cellulose?

Strach consists of amylose and amylopectin. Amylose is a linear polymer of $$\alpha-D-$$ glucose, while cellulose is a linear polymer of $$\beta-D-$$ glucose. In amylose $$C-1$$ of one glucose unit is connected to $$C-4$$ of the other through $$\alpha-$$ glcosidic linkage (see section $$17.3.19$$). However, in cellulose $$C-1$$ of one glucose unit is connected to $$C-4$$ of the other through $$\beta-$$ glycosidic linkage (see Section $$17.3.20$$). Amylopectin on the other hand, has a highly branched structure.

Name two biologically important compounds that contain both oxygen and nitrogen.

DNA (Deoxy ribonucieic acid ) and RNA (Ribonucleic acid) are two biologically important compounds that contain both oxygen and nitrogen. Oxygen is present in pentose sugar (Ribose in case of RNA and Deoxy ribose in case of DNA) and nitrogen is present in nitrogenous bases (purines and pyrimidine).

Arrange the order of increasing acidic strength.

$$(X) > (Z) > (Y)$$

Carboxylic acids are stronger acids than $$(-NH_3)$$ group. Hence $$(X)$$ is the strongest acid. Due to $$-I$$ effect of $$(-COOH), (Z)$$ is more acidic than $$(Y)$$. Its $$-I$$ effect is short distance operating from the source, so stronger is the acid. Since $$(Z)$$ is nearer to $$(-COOH)$$ group, $$(Z)$$ is more than $$(Y)$$. Hence the order is as given above.

Name the link connecting monosaccharide unit in polysaccharides.

The link connecting the monosaccharide unit and polysaccharides is a glycosidic linkage.

Carbohydrates and _-provide___ to our body.

Carbohydrates and fats provide energy to our body.

Write any two methods for the preparation of glucose.

(i) Preparation of glucose from sucrose:

On boiling an aqueous solution of sucrose with dilute HCl or dilute $$ H_2SO_4 $$ , glucose and fructose are formed in equimolar proportions.

$$ C_{12}H_{22}O_{11} + H_2O \xrightarrow{H^+} C_6H_{12}O_6 + C_6H_{12}O_6 $$

Sucrose Glucose Fructose

(ii) Preparation of glucose from starch :

Starch , when boiled with dilute $$ H_2SO_4 $$ at $$393\,K $$ under $$2$$ to $$3$$-atmosphere pressure , gives glucose.

$$ (C_6H_{10}O_5)_n + nH_2O \xrightarrow[393\,K , 2 to 3 atm]{H^+} nC_6H_{12}O_6 $$

Enzymes are proteins. Proteins are long chains of amino acids linked to each other by peptide bonds. Amino acids have many functional groups in their structure. These functional groups are, many of them at least, ionisable. As they are weak acids and bases in chemical nature, this ionization is influenced by pH of the solution. For many enzymes, activity is influenced by surrounding pH. This is depicted in the curve given, explain briefly.

$$\textbf{Explanation:}$$

$$\bullet$$ The graph below shows the activity of enzymes at a particular pH.

$$\bullet$$ There is a pH at which the enzyme activity is maximum (the optimal pH), it is around 7 for enzymes of human body. When the pH rises more than the optimum pH, the enzymatic activity or the reaction velocity decreases.

$$\bullet$$ Similarly if we go below the optimum pH (decrease in pH below optimum value) enzyme activity/reaction velocity decreases.

$$\bullet$$ Changes in pH can make and break intra- and intermolecular bonds, changing the shape of the enzyme and, therefore, its effectiveness. We observe a bell shaped curve between enzyme activity and pH.

Write the name of the disease caused by the deficiency of vitamin $$ B_{12} $$ and vitamin A. Also, write the source of these vitamins.

Vitamins	Deficiency disease	Sources
Vitamin $$B_{12}$$	Pernicious anaemia, inflammation of tongue and mouth	Milk, egg, animal tissue
Vitamin $$A$$	Night blindness, stunted growth, xerophthalmia	Milk, butter, papaya, tomato, carrot

Write the name of nitrogenous bases found in DNA.

Purine Bases: Adenine (A) , Guanine(G)

Pyrimidine Bases : Cytosine (C) , Thymine (T)

What are the constituent elements of sugar?

The constituent elements of sugar are Carbon, Hydrogen, and Oxygen.

Why are hormones known as 'glandular juice' ?

Hormones are known as 'Glandular Juices' because they are secreted by endocrine glands.

Which vitamin is soluble in water ?

Vitamins B , and C are soluble in water.

The compound in food materials are given, Filling the missing ones
a)Carbohydrates - Carbon, Hydrogen
b)Protein - Carbon, Hydrogen, oxygen
c)Fats - Carbon, Hydrogen

a) Carbohydrates - Carbon, Hydrogen, $$Oxygen$$
b) Protein - Carbon, Hydrogen, oxygen, $$Nitrogen$$
c) Fats - Carbon, Hydrogen, $$Nitrogen$$

Biochemical reactions are regulated by catalysts called ...........

A substance that speeds up a chemical reaction without being a reactant is called a catalyst.
Biocatalyst which regulate every reaction in a living organism are enzymes.
Enzymes are usually proteins (more than 90%), though some ribonucleic acid (RNA) molecules act as enzymes too.

The structure of Adenosine triphosphate (ATP) molecule is given above. The value of $$n_{1}+n_{2}$$ is (where $$n_{1}$$ is the net negative charge in neutral medium and $$n_{2}$$ is number of chiral carbon atoms)

In a neutral medium, the phosphates will ionise to give a net negative charge of 4.
So, $$n_{1}=4$$
The number of chiral carbon atoms is 4.
So, $$n_{2}=4$$
Thus, $$n_{1}+n_{2}=8$$.

Match the one-letter code for each amino acids:

The correct symbol for given amino acids are:

Lysine - K

Glutamic acid - E

Histidine - H

Asparagine - N

Hence, A-2, B-4, C-1, D-3 is the correct answer.

Give two examples of water soluble vitamins.

Vitamin B-complex and vitamin C are water-soluble vitamins that are not stored in the body and must be replaced each day.

Which polysaccharide component of carbohydrates is commonly present in bread?

Polysaccharides are complex carbohydrates, composed of up to several thousand monosaccharides arranged in chains. The main component of polysaccharide present in bread is starch.

What are hormones? Write the structure of simple triglycerides.

Hormones are the secretions of endocrine (ductless) glands. These glands discharge their secretions directly in the blood. The blood provides the required chemicals in the form of raw materials for secretion of hormones and also acts as a vehicle for transport of hormones to reach the specific organs of the body.
The structure of simple triglyceride (Refer image).

Match the following and choose the correct option.

Explanation:

$$A-2$$, Ribose is a nucleic acid component.

$$B-3$$, Biotin, often known as vitamin. It is a vitamin.

$$C-4$$, An enzyme is a protein that is connected to a globular protein.

$$D-1$$, Glycine is an amino acid. Ninhydrin provides a color test for amino acids.

Final Answer:

Hence the correct answer is,

$$A-2$$

$$B-3$$

$$C-4$$

$$D-1$$

Explain the classification of hormones in detail.

Hormones are classified on the basis of their chemical structure. They are as follow:

1) Amine hormones: They are formed from amino acids and some modified groups. Examples include epinephrine, thyroxine.

2) Peptide hormones: They contain short chains of linked amino acids. Examples include oxytocin, vasopressin.

3) Protein hormones: They contain long chains of linked amino acids. Examples include human growth hormones such as GTH, TTH and STH.

4) Steroids hormones: They are formed from cholesterol. Examples include testosterone, progesterone, aldosterone

5) Fatty acid hormones: They are formed from fatty acid derivatives. Example include prostaglandin.

Amino acids show amphoteric behaviour. Why?

An amphoteric substance is one which can act as an acid as well as a base.
Amino acids show amphoteric behavior. Aminoacids are bi-functional molecules. They contain carboxylic ($$-COOH$$) group that acts as an acid and an amino ($$-NH_2$$) group that acts as a base.

Give the main sources of Vitamins $$A,C$$ and $$D$$. Write down the names of diseases caused by their deficiency.

Vitamin	Sources	Deficiency diseases
A	It occurs in free state or as ester in milk, butter, eggs, fish and vegetables such as cabbage and carrots.	Night blindness, retardation of growth and dryness of skin/hair.
C	Citrus fruits and green vegetables.	Scurvy
D	Cod liver oil, fish liver oil, meat, egg, butter etc.	Rickets, a disease related to bones

Name an enzyme where RNA acts as a biological catalyst.

A ribozyme is an enzyme where RNA acts as a biological catalyst. It is also called catalytic RNA which is found in ribosomes where they join amino acids together to form protein chains.

What are carbohydrates? Classify them and also write their characteristics.

Carbohydrates are optically active polyhydroxy aldehydes or polyhydroxy ketones or the compounds that can be hydrolysed to polyhydroxy aldehydes or polyhydroxy ketones.
Carbohydrates are classified into simple carbohydrates and complex carbohydrates.
Simple carbohydrates are also known as monosaccharides and include aldoses and ketoses.
Complex carbohydrates include oligosaccharides (disaccharides, trisaccharides, tetrasaccharides etc.) and polysaccharides.
Characteristics of carbohydrates
Carbohydrates are simple sugar molecules composed of the elements carbon, hydrogen and oxygen. The ratio of $$C, H$$$ and $$O$$ is usually $$1:2:1$$. A carbohydrate contains a chain of sugar molecules called monosaccharides.

What kind of reaction do Dehydrogenases enzymes catalyse?

Dehydrogenases help in removal of hydrogen which is also called as oxidation. Oxidation is a process in which electrons are removed from a molecule or atom. That means oxygen molecule is added and hydrogen molecule is removed in the process.

Differentiate between Starch and Glucose.

Starch	Glucose
It is polysaccharide	It is monosaccharide
It contains two fractions, amylose (20%) and amylopectin (100%).	It contains only one fraction which is glucose (100%)

Are enzymes specific for only specific compounds? Explain.

Enzymes are highly selective catalysts, meaning that each enzyme only speeds up a specific reaction. The molecule that an enzyme works with are called substrates. The chemical reactions result in a new product or molecule that then separated from the enzyme, which goes on to catalyze other reactions.

Why are enzymes specific, and why can not each one speed up many different reactions?

Each enzyme is specific to a chemical reaction it will affect because each enzyme contains an active site which is an area of an enzyme that has specific shape and size and differs from one enzyme to the another. The active site is shaped in a way that only a specific substrate can fit into the active site of an enzyme.

Write short notes on the following:
(a) Enzyme specificity (b) Enzyme inhibition

(a) Enzyme specificity- It the ability of an enzyme to bind with the specific substrate or catalyze a specific set of chemical reactions. It depends upon the active site orientation based on its atomic configuration. Bond breaking and forming reacting groups are in the active site of the enzyme. In this type, the enzyme is not only specific to the type of the bond but also the structure surrounding it.

(b) Enzyme inhibition- It is a molecule that binds the enzyme and suppresses its activity. They may cause a reduction in the rate of an enzyme catalysed the reaction. These can be specific or non-specific, reversible and irreversible, competitive or non-competitive. The binding of an inhibitor can stop a substrate from entering into an active site.

Aspartame, an artificial sweetener, is a peptide and has the following structure
(I) Identify the four functional groups
(II) Write the zwitter ionic structure
(III) Write the structures of the amino acids obtained from the hydrolysis of aspartame
(IV) Which of the two amino acids is more hydrophobic?
$$H_2N-\underset{\underset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_2-COOH}{|}}{C}H-CONH-\overset{\overset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,CH_2-C_6H_5}{|}}CH-COOCH_3$$

$$\underset{2}{H}N-\underset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C\underset{2}{H}-COOH}{\underset{|}{CH}}-CONH-\overset{\,\,\,\,\,\,\,\,\,\,\,\,\,CH_2-C_6H_5}{\overset{|}{\,\,\,\,\,CH}}-COOCH_3$$

(1) The 4 functional groups are - $$NH_2$$ (Ammonia)/(Amine)

- $$CONH$$ (Amide)

- $$COOH$$ (carboxylic Acid)

- $$COOCH_3$$ (Either)

(2) Zwitter ionic structure:

$$\left[\underset{2}{H}\overset{+}{N}-\underset{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,C\underset{2}{H}-COO^-}{\underset{|}{CH}}-CONH-\overset{\,\,\,\,\,\,\,\,\,\,\,\,\,CH_2-C_6H_5}{\overset{|}{\,\,\,\,\,CH}}-COOCH_3\right]$$ Zwitter ion is a molocule with functinal groups, of which at least one has a positive and one has a negative electrical change.

(3) Refer image.

(4) Phenylalanine is more hydrophobic because its side chain is highly non-polar w.r.t. to others, so it will repeal water molecular.

1351461_1135419_ans_f2481f2fbd494377bc3b55b12d08a4cf.jpg

ATP ase enzyme consists of two parts. what are those parts ? How are they arranged in the thylakoid membrane ? Conformational change occurs in which part of the enzyme ?

ATPase enzyme are found in the thylakoid membranes of chloroplasts, and in the inner membranes of mitochondria.

Give scientific reason: Microbial enzymes are said to be eco-friendly

The biocatalytic potential of microorganisms has been employed for centuries to produce bread, wine, vinegar, and other common products without understanding the biochemical basis of their ingredients. Microbial enzymes have gained interest for their widespread uses in industries and medicine owing to their stability, catalytic activity, and ease of production and optimization than plant and animal enzymes. The use of enzymes in various industries (e.g., food, agriculture, chemicals, and pharmaceuticals) is increasing rapidly due to reduced processing time, low energy input, cost-effectiveness, nontoxic and eco-friendly characteristics. Microbial enzymes are capable of degrading toxic chemical compounds of industrial and domestic wastes (phenolic compounds, nitriles, amines etc.) either via degradation or conversion.

Answer the following questions:

Write Haworth projection formula of $$\alpha -D-(+)-$$glycopyranose.
Define hormones.

$$\alpha -D-(+)-$$glucopyranose.

Hormones:
A chemical substance produced in the body that controls & regulates the activity of certain cells & organs. Many hormones are secreted by special glands, such as thyroid hormone produced by thyroid gland.

1495293_1700047_ans_3a355e296e914a59bbd4dc6d2d0292a4.png

Define the following terms with a suitable example:
Polysaccharides

Polysaccharides contain long monosaccharide units joined together by glycosidic linkage.

Most of them act as food storage for e.g. Starch. Starch is the main storage polysaccharide for plants.

It is a polymer of α glucose and consists of two components-Amylose and Amylopectin.

Cellulose is also one of the polysaccharides that are mostly found in plants.

Write the reaction of an amino acid with ninhydrin reagent?

When an excess of ninhydrin, which is originally yellow in color, reacts with a free $$α-amino$$ acid group, a $$purple$$ colored dye known as Ruhemann's purple is formed along with an aldehyde and liberation of $$CO_2$$ gas(primary amines does not liberate $$CO_2$$). The presence of Ruhemann's purple imparts purple color to the product which forms the basis of the Ninhydrin test in order to detect amino acids.
1795516_1720577_ans_53f6dd23f86e46ac8e91a7ef4a4cc817.png

1795516_1720577_ans_53f6dd23f86e46ac8e91a7ef4a4cc817.png

Fill in the blanks:
A disaccharide consists of two ..... joined by ..... bonds.

$$\text{A disaccharide consists of two }monosaccharides\text{ joined by }glycoside\text{ bonds.}$$

For example,

(1) Sucrose is a disaccharide containing two monosaccharids glucose and fructose joined by glycoside bonds.

(2) Maltose is a disaccharide containing two monosaccharids glucose and glucose joined by glycoside bonds.

(3) Lactose is a disaccharide containing two monosaccharids glucose and galactose joined by glycoside bonds.

Fill in the blanks:
A polysaccharide is a polymer of ..........

$$\text{A polysaccharide is a polymer of }monosaccharides.\text{ For example cellulose (a polysaccharide) is a polymer of}$$ $$\text{D-glucose (monosaccharide).}$$

Fill in the blanks:
Protein is a polymer of......

$$\text{Proteins are polymers made out of }amino\ acids.\text{ They are naturally occurring, meaning they are made by}$$ $$\text{animals, plants, bugs, fungi, and other living things. A protein is actually a polyamide. So, proteins are polymers}$$ $$\text{of} \ amino\ acids.$$

Fill in the blanks:
A compound that contains both.....and......is called amino acid.

A compound that contains both $$amine(-NH_2)$$ and $$carboxylic \ acid(-COOH)$$ is called amino acid. Amino Acids are Linked by peptide bonds formed by linking the α-carboxyl group of one amino acid to the α-amino group of another amino acid.

Fill in the blanks.
Amino acids are the end products of the digestion of .......

$$\text{Amino acids are the end products of the digestion of }proteins.\text{ Once consumed, proteins are digested}$$ $$\text{and broken down into amino acids by enzymes.}$$

Fill in the blank
Exposure of body to sunrays produces...

$$\text{Exposure of the body to sunrays produces }vitamin \ D.$$ When the sun’s ultraviolet B (UVB) rays hit a person’s skin, processes inside the tissue start making vitamin D for the body to use. It is essential to remember, however, that too much sun exposure can burn the skin and potentially lead to skin cancer.

Name the sources of following vitamins: Vitamin A

$$\text{Vitamin A is synthesised in cells of liver and intestinal mucous membrane from carotenoid pigments found in milk,}$$ $$\text{butter, egg yolk, liver, fish oil, etc.}$$

What happens when
Alanine is treated with nitrous acid

1545983_1722420_ans_69e485585e224a72a7c491f26ddf6f94.jpg

Name the sugars present in nucleic acid

$$\text{deoxyribose and ribose}$$

$$\text{The pentose sugar in DNA is called deoxyribose, and in RNA, the sugar is ribose. The difference between the}$$ $$\text{sugars is the presence of the hydroxyl group on the 2' carbon of the ribose and its absence on the 2' carbon of}$$ $$\text{the deoxyribose.}$$

What is nucleoside ? when does it become nucleotide ?

$$\text{The molecule in which one of the organic bases linked with sugar is called nucleoside and when phosphate group}$$ $$\text{is also attached the compound is known as a nucleotide.}$$

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Find the average molecular mass of starch given that an aqueous solution of 10.0 g/L of starch has an osmotic pressure $$5.0\times 10^{-3}$$ atm at $$25^{\circ}C$$. What is the approximate number of glucose units in this sample of starch?

Osmotic pressure $$ \dfrac{w}{M\times V}\times R \times T $$

$$M = \dfrac{w}{P\times V}\times R\times T $$

$$M = \dfrac{10}{5\times 10^{-3}\times 1}\times 0.0821\times 298 = 48931.6$$ g/mol

Each glucose unit in starch has molecular mass
$$= 180-18 = 162 $$ g/mol

The number of glucose units in the sample of starch
$$ = \dfrac{4893.6}{162} = 302 $$

Name the base present in RNA

$$\text{Four nitrogen-containing nucleobases: adenine, uracil, guanine, and cytosine are present in RNA }$$while DNA contains four nitrogenous nucleobases: adenine, thymine, cytosine, and guanine.
1815669_1722424_ans_e74277cf27104c9c960a1709f7811c11.PNG

1815669_1722424_ans_e74277cf27104c9c960a1709f7811c11.PNG

Name the sources of following vitamins: Vitamin C

$$\text{The sources of Vitamin C is Lemon, orange and other citrus fruits, tomatoes, green vegetables, etc.}$$

Name the monosaccharides which the following give on hydrolysis?
(a) sucrose (b) lactose (c) maltose (d) Raffinose

(A) Sucrose is made up of glucose and fructose molecules. When sucrose is consumed, the enzyme separates sucrose into its individual sugar units of glucose and fructose.

(B) Lactose is a disaccharide, a type of sugar composed of two simple sugars, glucose and galactose.

(D) Raffinose is a trisaccharide composed of galactose, glucose, and fructose.

What happens when $$S-$$ glucose is treated with the following reagents?
$$HNO_{3}$$

1747042_1769274_ans_2da68ab781b94df6acc434bd6df6f46c.png

Which of the two components of starch is water soluble ?

Two components of starch are Amylose and Amylopectin. Out of which, Amylose is water soluble whereas amylopectin is water insoluble component.

Seema likes sugar apple which is a multiple purpose , an all-rounder fruit . It can be used by athletes as high calorie fruit for high energy. The powder of its seeds is an effective pesticide in agriculture and horticulture and also used to remove head lice. Its leaves have anti-diabetic properties . The alcoholic extract of its leaves and stems can treat tumours . This extract is an antidepressant . Fruits are sweet and increase the haemoglobin , cooling and act as sedative. Seeds are insecticides . Its roots are powerful purgatives and used in dysentery.
Why should we use it as a pesticides and insecticides instead of chemicals ? Which value is associated with its use ?

1709915_1773665_ans_e464b28496b54586b383eff4c7e7ed40.jpg

Why are carbohydrates generally optically active ?

Generally, Carbohydrates are optically active because they have chiral or asymmetric carbon atom.

What is the major structural polysaccharide in higher plants ?

The major structural polysaccharide in higher plants is Cellulose.

Seema likes sugar apple which is a multiple purpose , an all-rounder fruit . It can be used by athletes as high calorie fruit for high energy. The powder of its seeds is an effective pesticide in agriculture and horticulture and also used to remove head lice. Its leaves have anti-diabetic properties . The alcoholic extract of its leaves and stems can treat tumours . This extract is an antidepressant . Fruits are sweet and increase the haemoglobin , cooling and act as sedative. Seeds are insecticides . Its roots are powerful purgatives and used in dysentery.
Why is sugar apple used by athletes ?

1709908_1773660_ans_f6ad6ca9feec419884a7b971bd5076f6.jpg

What are nucleic acids? Mention their two important functions.

A nucleoside is formed when $$1-$$ position of pyrimidine (cytosine, thiamine, or uracil) or $$9-$$ position of purine (guanine or adenine) base is attached to $$C-1$$ of sugar (ribose or deoxyribose) by a $$\beta$$- linkage. Thus in general nucleosides may be represented as: sugar base. For examples structure $$(I)$$ represents a nucleoside.

A nucleotide contains all the three basic components of nucleic acids i.e. a phosphoric acid group, pentose sugar and a nitrogenous base. These are obtained by the esterification of $$(C'_{5}-OH)$$ group of the pentose sugar by phosphoric acid.

Thus in general a nucleotide is represented as structure $$(II)$$ represents a nucleotide.

1747857_1769293_ans_992ecb3623694ceda6fd848795a8ae6e.png

Write the structure of alanine at $$pH=2$$ and $$pH=10$$.

At $$pH=2$$, basic $$NH_2$$ reacts with $$H$$

Since $$pH=2$$ is acidic.

At $$pH=10$$, basic $$COOH$$ reacts giving $$H^+$$
Since $$pH=10$$ is basic
1756214_1769375_ans_7f0f1860ad264a38b61f87bd6ffd10eb.png

Name the two components which constitutes starch.

The two components which constitutes starch are amylose and amylopectin.

Give two examples of water-soluble vitamins.

Two examples of water-soluble vitamins are Vitamin $$ B $$ & Vitamin $$ C $$.

What type of linkage is present in nucleic acids ?

Phosphodiester linkage is present in nucleic acids.

Define Glycosidic linkage

The linkage between two monosaccharides through oxygen atom in an oligosaccharide or a polysaccharide is known as Glycosidic linkage.

State two main functions of carbohydrates.

The two main functions of Carbohydrates are as follows:

$$(i) $$. Carbohydrates act as biofule to provide energy for functioning of living organisms.
$$ (ii) $$. They act as constituents of cell walls.

Among B group vitamins $$ B_1, B_2, $$ and $$ B_{12} $$ which vitamin can be stored in our body ?

Vitamin $$ B_{12} $$ can be stored in our body and it is stored in Liver.

Name the enyme that is used to dissolve blood clots.

The enyme that is used to dissolve blood clots is $$ Streptokinase. $$

Name the enzymes that breaks large protein into small peptides.

The enzymes that breaks large protein into small peptides are Pepsin & Trypsin.

Out of aspartic acid and ascorbic acid which one in a vitamin?

Out of the two, Ascorbic acid is a vitamin.

Name two water-soluble vitamins. State their sources and the diseases caused due to their deficiency in the diet.

B group vitamin and vitamin C are soluble in water.

	Name of vitamins	Sources	Deficiency diseases
(i)	Vitamin $$ B_{12} $$	Meat, Fish, egg and curd	Pernicious anaemia
(ii)	Vitamin $$ C $$	Critrus fruits	Scurvy

Give the chemical name of vitamin $$ B_{12} $$

Chemical name of $$Vitamin \ B_{12} $$ is Cyanocobalamin.

Define Enzymes.

Enzymes are complex nitrogenous organic compounds produced in living cells of plants and animals. Chemically, enzymes are globular proteins with high molar mass ranging from $$ 15000 $$ to $$ 1,000,000 g mol^{-1} $$

Define Amino acids

Amino acids are the compounds whose molecule contains both carboxylix acid $$ (-COOH) $$ groups and the amino $$ (-NH_2) $$ group. of the various amino acids , the $$\alpha$$-amino acids are most important because they are the building blocks of proteins.

Give one example each for water-soluble vitamins and fat-soluble vitamins

Vitamin $$ C $$ and $$ B $$ group vitamins are water soluble vitamins.
Vitamin $$ A , D , E $$ and $$ K $$ are fat soluble vitamins.

Amino acids show amphoteric behaviour. Why ?

In aqueous solution, amino acids exist as a zwitter ion form , amino acids show amphoteric behaviour as they react both with acids and bases.
in acidic medium $$ COO^- $$ ion of the zwitter ion accepts a proton to for the cation (i) while in basic medium $$ NH_3^+ $$ loses a proton to form the cation (II).
1645838_1781534_ans_9e355f8790274d74b5f3d989ff713232.png

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Define Polysaccharides

Carbohydrates that yeild a large number of monosaccharide units hydrolysis are called Polysaccharides.

For e.g.starch, cellulose, etc.

Name the three major classes of carbohydrates and give an example of each of these classes.

Monosaccharides : The simple carbohydrates that cannot be broken further into smaller units in hydrolysis,

e.g. glucose and fructose , ribose , etc

Oligosaccharides : these are the carbohydrates which on hydrolysis give two to ten units of monosaccharides

e.g. sucrose, maltose, raffinose, stachyose etc.

Polysaccharides : These are the carbohydrates which produce a large number of monosaccharide units on hydrolysis.

e.g. starch , cellulose etc.

Which one of the following is a polysaccharide?
Starch, Maltose, Fructose, Glucose

Of the given carbohydrates, $$ Starch $$ is a polysaccharide.

Which of the following biomolecules is insoluble in water? justify.
Insulin, Haemoglobin, Keratin

As Fibrous proteins are insoluble in water and Keratin being a fibrous protein is insoluble in water.

Give one structural difference between amylose and amylopectin.

Amylose is a long unbranched chain polymer of $$ \alpha-D(+) $$ glucose.
Amylopectin is a branched chain polymer of $$ \alpha-D(+)$$ glucose.

What are glycosidic linkages? In which type of biomolecules are they present?

The two monosaccharides are joined together by an oxide linkage formed by the loss of a water molecule. Since a linkage between two monosaccharides is held together by a glycosidic linkage between $$C1$$ of $$\alpha$$ glucose and $$C2$$ of $$\beta $$ fructose. Since the reducing groups of glucose and fructose are involved in glycosidic bond formation, between two monosaccharide units through oxygen atom is called glycosidic, linkage.
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How protein is synthesized by nucleic acid ? Explain.

Synthesis of protein:

Protein synthesis is another important function of nucleic acids. The process of protein synthesis is a very complex process. As stated earlier, $$20$$ main acids combine in different ways to synthesis protein. Living cells have above $$200$$ enzymes and more than $$70$$ RNA take part in protein synthesis. Protein synthesis is done by different RNA molecules. DNA provides code for protein synthesis.

The synthesis of protein takes place in two steps:

1. Transcription:

Transmission of heredity information to RNA.

2. Translation:

Transmission of information from RNA to protein, the synthesis of protein from DNA can be represented as shown:

1. Transcription: The process which leads to the synthesis of RNA is called transcription. It can also be defined as the process of copying genetic information from one strand of the DNA into RNA is termed as transcription. Three types of RNA takes part in protein synthesis (m-RNA, r-RNA and t-RNA) which are synthesized by DNA.

Transcription involves the binding of RNA-polymerase at the promoter site on DNA. As it moves along (through structural gene), the DNA unwinds and one of the two strands acts as a template to synthesize a meaningful RNA and other strand act as non-coding. A complementary RNA strand is synthesized with A, U, C and G as bases. RNA synthesis is terminated when the RNA-polymerase falls off a terminator sequence on the DNA.

2. Translation: This process is very complex. The formation of protein from m-RNA is known as translation. More than 100 macromolecules are used in this process such as m-RNA, t-RNA, ribosomes etc. It refers to the process of polymerization of amino acids to form a polypeptide. The order and sequence of amino acids are defined by the sequence of bases in the m-RNA. The amino acids are joined by a bond which is known as a peptide bond. Protein synthesis takes place in the cytoplasm.

After transcription, m-RNA moves to a ribosome in cytoplasm form nucleus. r-RNA components of ribosomes. The base sequence in RNA is studied in three groups. This group of three nucleotide triplet is known as a codon. Each codon represents a particular amino acid. t-RNA has a specific sequence of bases at the ends which are complementary to the base sequence of m-RNA. At the other end of t-RNA, a specific amino acid is attached.

In ribosomes, amino acids retransferred from t-RNA to m-RNA. Those amino acids whose base sequence in m-RNA are bonded by m-RNA through peptide linkage. In this way, the polypeptide chain is formed and protein synthesis takes place. In proteins, a sequence of amino acids is determined by m-RNA and in m-RNA, a base sequence is determined by DNA. This means that the translation of amino acids takes place by DNA on ribosomes.

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Write the general chemical reactions of glucose.

General chemical reactions of glucose can be grouped under two categories:

(A) Reactions due to alcoholic groups:

There are four secondary and one primary alcoholic groups present in a molecule of glucose. Some of the reactions of alcoholic groups are as follows:

(i) Acetylation :

$$ CHO $$ $$ CHO $$

$$ \mid $$ $$ \mid $$

$$ (CHOH)_4$$ $$ + 5 (CH_3CO_2)_2O \rightarrow (CHOCOCH_3)_4 + 5 CH_3COOH $$

$$ \mid $$ $$ \mid $$

$$ CH_2OH $$ $$ CH_2OCOCH_3 $$

Glucose Pentaacetyl Glucose

(ii) Methylation : (Refer Image)

Glucose reacts with methyl alcohol in the presence of dry HCl gas forming methyl glucoside which is an ether.

(B) Reactions due to aldehydic $$(-CHO)$$ group

(i) Reduction :

When reduced with Na-Hg and water , the $$-CHO $$ group in glucose is reduced to a primary alcoholic group to give sorbitol.

$$ CH_2OH (CHOH)_4 CHO + 2 [H] \rightarrow CH_2OH(CHOH)_4CH_2OH $$

Glucose Sorbitol

When reduction is carried with HI and red P, the product is n-hexane. This suggests that all six carbon atoms in glucose are linked to form a straight chain.

$$ CHO(CHOH)_4CH_2OH \xrightarrow[reduction]{HI/P} CH_3(CH_2)_4CH_3 $$

Glucose n-Hexane

(ii) Oxidation :

With mild oxidizing agent like $$ Br_2 $$ water , glucose is oxidized to gluconic acid which is a carboxylic acid. This shows that the carbonyl group present in glucose is an aldehydic group

$$ CH_2OH (CHOH)_4 CHO \xrightarrow[Oxidation]{Br_2/H_2O} CH_2OH(CHOH)_4COOH $$

Glucose Gluconic acid

In case the oxidation is carried out with conc. $$HNO_3 $$ the primary alcoholic group oxidized to carboxyl group to form a dicarboxylic acid which is Saccharic acid

(iii) Reaction with hydrogen cyanide :

Glucose forms a cyanohydrin derivative with hydrogen cyanide.

(iv) Reaction with hydroxylamine :

Glucose reacts with hydroxylamine to form an oxime.

$$ CH_2OH(CHOH)_4CHO + NH_2OH \rightarrow CH_2OH(CHOH)_4CH = NOH + H_2O $$

Glucose Glucose oxime

(v) Action with Tollen's Reagent :

When Tollen's reagent is heated with glucose in a clean test tube, a shining mirror gets deposited at the bottom of the test tube.

$$ AgOH + 2NH_4OH \rightarrow Ag(NH_3)_2OH + 2H_2O $$

$$ CHO $$ $$ COOH $$

$$ \mid $$ $$ \mid $$

$$ (CHOH)_4 + 2Ag(NH_3)_2OH \rightarrow (CHOH)_4 + 2Ag \downarrow + 4NH_3 + H_2O $$

$$ \mid $$ $$ \mid $$

$$ CH_2OH $$ $$ CH_2OH $$

Glucose Gluconic acid

(vi) Action with Fehling's Solution :

When heated with glucose , Fehling solution gives a red precipitate.

$$ CHO $$ $$ COOH $$

$$ \mid $$ $$ \mid $$

$$ (CHOH)_4 + 2Cu^{2+} + 4OH^- \rightarrow (CHOH)_4 + Cu_2O + 2H_2O $$

$$ \mid $$ $$ \mid $$ Red ppt.

$$ CH_2OH $$ $$ CH_2OH $$

Glucose Gluconic acid

(vii) Reaction with Phenyl Hydrazine :

Glucose contains in it an aldehydic group and is expected to react with phenylhydrazine to form phenylhydrazone. However when the excess of phenylhydrazine is used the product formed is an osazone i.e., glucosamine.

$$ CHO $$ $$ CH = NNHC_6H_5 $$

$$ \mid $$ $$ \mid $$

$$ CHOH $$ $$ CHOH $$

$$ \mid $$ $$ \mid $$

$$ (CHOH)_3 \xrightarrow[-H_2O]{C_6H_5NHNH_2} (CHOH)_3 \xrightarrow[-C_6H_5NH_2-NH_3]{C_6H_5NHNH_2} $$

$$ \mid $$ $$ \mid $$

$$ CH_2OH $$ $$ CH_2OH $$

Glucose Phenyl hydrazone Glucose

$$ CH = NNHC_6H_5 $$ $$ CH = NNHC_6H_5 $$

$$ \mid $$ $$ \mid $$

$$ C = O $$ $$ C = NNHC_6H_5 $$

$$ \mid $$ $$ \mid $$

$$ (CHOH)_3 $$ $$(CHOH)_3 $$

$$ \mid $$ $$ \mid $$
$$ CH_2OH $$ $$ CH_2OH $$
Glucosazone

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Write notes on Polysaccharides.

Polysaccharide are the most abundant carbohydrated found in food. They are long chain polymeric carbohydrates composed of monosaccharide emites bound together by glycoside linkage.

This carbohydrate react with water using amylase enzymes at catalyst which produces constituent sugars (monosaccharide and oligosaccharides)

Nutrition polysaccharides are common sources of energy many organisms can easily break down starch into glucose which provides energy to organisms.

Write the names and biological functions of hormones secreted by the pituitary gland and thyroid gland.

Sr. No.	Gland	Position	Hormone and their nature	Biological Functions
1	Pituitary	Beneath brain	(i) Follicle-stimulating hormone (FSH) (Protein)	Stimulates spermatogenesis in male growth of ovarian follicles in females.
	(a)Anterior lobe		(ii) Luteinising hormone (LH) (protein)	Induces testosterone secretion in males. Ovulation and secretion of estrogen and progesterone in females. Ovulation and secretion of estrogen and progesterone in females.
			(iii) Somatotrophin (STH) (Protein)	Regulates protein metabolism and growth of bones. Deficiency causes dwarfism, excess produce gigantism in young and acromegaly in adults.
			(iv)Prolactin(Protein)	Controls development of milk glands
			(v)Adrenocorticotrophin (ACTH) (Peptide)	Stimulates secretion of hormones of the adrenal cortex.
			(vi) Thyrotrophin (TSH) (Protein)	Stimulates secretion of thyroid hormone.
	(b)Intermediate lobe		(i) Melanocyte stimulating hormone (MSH) (Peptide)	Controls skin colour.
	(c) Posterior Lobe		(ii) Oxytocin(peptide)	Regulate uterine contraction and release of milk.
2	Thyroid	Front of larynx	(i) Thyroxine	Regulates oxidation of food, excess causes exophthalmic goiter.
			(ii) Triiodothyronine	Deficiency produces cretinism in children, myxoedema in adults. Also controls the working of kidneys. Deficiency also reduces urine output.
			(iii) Calcitonin (CT)	Controls calcium and phosphorous balance.

What are the main sources of cellulose and starch? Explain their structure in brief.

Cellulose $$ (C_6H_{10}O_5)_n $$

Sources:

Cellulose occurs exclusively in plants and is the most abundant organic substance in the plant kingdom. It is a predominant constituent of the cell wall of the plant cell. It is present in wood, cotton clothes, jute, cotton, etc. in wood, it is present $$50$$%, in dry grasses, it is $$40 - 45$$%, injure $$ 60 - 65$$%, in cotton $$90 - 95$$ %, in cotton clothes $$90$$% cellulose and rest in fats and waxes.

Structure: Cellulose is composed of $$ \beta $$-D-glucose units linked by $$ (1 \rightarrow 4)$$ glycosidic bonds. The X-ray analysis has shown that there are large linear chains of $$ \beta $$ - D(+) glucose molecules lying side by side in the form of bundles held together by H - bonding in the neighboring hydroxyl groups. In each linear chain, the D(+) glucose unit are attached to each other by $$C_1$$ to $$C_4$$ bonds through $$ \beta $$ – glycosidic linkages as shown below.

(ii) Starch $$ (C_6H_{10}O_5)_n $$

Sources:

Starch is a major source of carbohydrates which are very much essential to the human body since they supply energy to the body. It occurs as granules mainly in seeds, fruits, tubers, and also in the roots of plants. The chief commercial sources of starch are wheat, maize, rice, potatoes etc.

Structure:

Starch consists of two polysaccharide components. They are

(a) Amylose $$15$$% - $$20$$% soluble in water.

(b) Amylopectin ($$80$$% - $$90$$%) insoluble in water.

$$ (C_6H_{10}O_5)n \longrightarrow (C_6H_{10}O_5) \rightarrow C_{12}H_{22}O_{11} \rightarrow C_6H_{12}O_6 $$

Starch $$ (n, < n) $$ Maltose D-glucose

2030096_1832071_ans_991eb819a85a4cb18d062b147ceeab9e.jpg

What is the final product obtained by the hydrolysis of Starch?

Starch :

Upon hydrolysis with diastase enzyme starch give maltose.

$$ 2(C_6H_{10}O_5)_n + nH_2O \xrightarrow[Enzyme]{Diastase} n C_{12}H_{22} O_{11} $$

Starch Maltose

Describe the term $$D-$$ and $$L-$$ configuration used for an amino acid with examples.

Amino acid exists both in $$' D'$$ and $$'L'$$ forms. Most naturally occurring amino acids have a $$L-$$configuration. $$L-$$Amino acids are represented by writing the $$-NH_2$$ group on the left-hand side and $$D-$$ amino acids are represented by writing the $$-NH_2$$ group on the right-hand side.

Describe the structure of the enzyme and explain their specific characteristics.

All enzymes are made up of proteins but all proteins are not enzymes.
Many enzymes are made up exclusively of protein and such enzymes are called simple enzymes.
In many enzymes, there is found a non-protein part associated with protein. Such enzymes are known as conjugated enzymes or holoenzymes.
The protein part of the conjugated enzyme is called apoenzyme.
The nonprotein part of the conjugated enzyme is called the co-factor.
The co-factors are of three types:

Prosthetic group
Co-enzyme
Activator

Conjugated enzyme or Holoenzyme = Apoenzyme + Co-factor<br />
1. Prosthetic Group:

When the non-protein part attached with the apoenzyme is an organic compound and is firmly bonded with the protein part, it is called a prosthetic group.
The prosthetic group can not be separated from the protein part (the apoenzyme) without denaturation of the protein. Example: Cytochrome, Flavoprotein.

2. Co-enzyme:

When the non-protein part is an organic compound and is only loosely attached with the protein part (the apoenzyme), it is called as co-enzyme.
The co-enzyme can be easily separated from the protein part and can be easily attached again with it. Example: Co-enzyme A, NAD, FAD, NADP etc.

3. Activator:

When the non-protein part is an inorganic substance such as some metal ion or mineral ion, it is called as an activator.
The main role of the activator is to form a bond between the enzyme and the substrate molecule Example: K, Cu, Mn, Fe Zn, Ca, etc. Note: The main part of the holoenzyme or conjugated enzyme is made up of protein and it is called apoenzyme. The size (dimension) of the protein molecule and the sequence of amino acids varies in different enzymes.
As the proteins are colloidal in nature, they have large surface area per unit volume.
The protein part of the enzyme contains one or more specific sites called active sites. During the enzymatic activity, the substrate molecules attach at these active sites.
In the holoenzyme of the conjugated enzyme, the enzymatic activity is brought about by the holoenzyme.
The apoenzyme alone or the nonprotein part alone can not act as an enzyme.

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Biomolecules - Class 12 Engineering Chemistry - Extra Questions

Give the D form of glycine.

Name the nitrogenous base present in sphingolipids.

What are the functions of carbohydrates?

Write the name of deficiency diseases of Vitamin A, Vitamin $$B_1$$ , Vitamin C and Vitamin D.

Explain the amphoteric behaviour of amino acids.

Give example for four functional proteins

How will you prepare glucose from cane sugar.

Name the enzymes involved in the breakdown of nucleotides into sugars and bases?

Give the Free amino acids obtained on the hydrolysis of 'Aspartame'.

Draw the structure of fructose for haworth projection formulae.

Fructose $$\xrightarrow{Br_2/H_2O}$$ ?

Match List-I with List-II.

What are the different ways in which glucose is oxidised to provide energy in various organism ?

Match the compounds in column I with their characteristic(s)/test(s)/reaction(s)/reagent(s)/stereochemistry/isomer(s) given in column II. Matching can be one or more than one.

Describe in words the atomic composition denoted by chemical formula $$C_{12}\, H_{22}\, O_{11}$$.

What is pro-enzyme?

What are the products of hydrolysis of sugar?

Give two example of water-soluble vitamins.

Which component of starch is a branched polymer of $$\alpha$$-glucose and insoluble in water?

Which of the two components of starch is water soluble?

Define the following terms:(i) Glycosidic linkage(ii) Invert sugar(iii) Oligo saccharides

What is a glycosidic linkage?

Carbohydrates such as glucose, fructose and sucrose are sweet in taste. But, starch has bland taste though it is a carbohydrate. How do you account for this?

Does our blood have proteases and nucleases?

Give balanced equations for the following reactions:(i) How will you convert ethyl amine to methyl amine?(ii) What is the effect of denaturation on the structure of proteins?(iii) Name the nitrogen base residues present in DNA.

(a) Write the Haworth structure of sucrose.(b) Sucrose is a non-reducing sugar. Why?

Explain the preparation of glucose from cane sugar.

a) i) Name the water insoluble component of starch.ii) Mention one water soluble vitamin.iii) Is Lysine an essential or non-essential amino acid?b) Write the structure of Maltose.

Name the steps in the manufacture of common sugar from sugarcane and explain the first step.

Write the functional groups present in a molecule of Glycine.

Classify Vitamins $$A, B, C$$ and $$D$$ depending upon their solubility in water and fat and compare them.

Define carbohydrates. What are reducing and non-reducing sugars?

(a) What is fermentation? Give one example.(b) Write the balanced chemical equations of the reactions taking place in the manufacture of ethyl alcohol from sugar.

What are 'nucleic acids'?Define complex lipids. Mention any 'two' functions of lipids.

Mention any one hydrolytic product of lecithin.

Explain the functions of polysaccharides.

Give the classification of carbohydrates with examples.

State whether the following statements are true or false :(i) The general formula of alkanes is $${C}_{n}{H}_{2n+2}$$.(ii) Carbohydrates are body building nutrients.

What is a coenzyme?

Match the pairs correctly.

Write the properties of hormone.

Mention the difference between amylose and amylopectin.

Write the functions of the following vitamins:(i) Vitamin A (ii) Vitamin D(iii) Vitamin E (iv) Vitamin K

Cane Sugar, Glucose and Starch are Carbohydrates.(a) Represent the structure of Glucose.(b) Write a method to prepare Glucose from Starch. Write the chemical equation of the reaction.(c) Suggest any two uses of Carbohydrates.

Name two energy-providing nutrients.

What are vitamins? Write various kinds of vitamins?

Starch is __________ saccharide.

What are carbohydrates?

What is turn over number?

(a) What are enzymes ?(b)Discuss the mechanism of enzyme action.

Arrange the following carbohydrates in the order of increasing complexity of chemical structures: fructose, starch, oligosaccharide, maltose, triose.

How are enzymes able to enhance the rate of reaction ?

On the basis of 'sugar' differentiate D.N.A. and R.N.A:

Write down any two difference between nucleoside and nucleotide.

For a polymerization reaction: $$6HCHO\rightleftharpoons C_{6}H_{12}O_{6}$$ degree of association was found to be $$0.96$$. Calculate mean mass of mixture at equilibrium. Report value of mean molar mass of mixture dividing by $$50$$.

What are the main characteristics of an enzyme?

Define and give example of Essential amino acids :

Name the enzyme which catalyses the conversion of soluble fibrinogen into insoluble fibrin.

Short / Long answer type questions.What happens to the starchy part of a meal from the time it is eaten till it is made available to body tissues?

What was the discovery for which Sumner Was awarded Nobel Prize?

Name one element invariably found in proteins but not in all carbohydrates and lipids.

Differentiate between.Enzymes and inorganic catalysts

A substance that accelerates a chemical reaction, but itself is unchanged when the reaction is over, is a.......... In living systems, most of these substances are proteins known as..........

Write the general (empirical) formula for a carbohydrate.

Write only equation for the reactions for preparation of glucose from sugar and starch.

Write a short note on heterocyclic base present in nucleic acids. (structure is not required).

Write a note on significance of carbohydrates.

Which enzymes are called molecular scissors?

Preparation of soyabean milk and its comparison with the natural milk.

Write a short note on glycogen.

Explain the importance of carbohydrates.

Write a short note on starch:

Classify Amino acids on basis of function and on basis of Nature of amino acids.

Why Vitamin C can't be stored in our body?

How do you explain the amphotoric behaviour of aminoacids.

Why carbohydrates are important in our diet?

Enzyme catalyzed reaction proceed at rates vastly higher than that of uncatalysed reactions. prove this statement by taking a proper example.

What are amino acids?

Prepare Dipeptide from Alanine.

Define the following terms:
(i) Glycosidic linkage
(ii) Invert sugar
(iii) Oligo saccharides

Give balanced equations for the following reactions:
(i) How will you convert ethyl amine to methyl amine?
(ii) What is the effect of denaturation on the structure of proteins?
(iii) Name the nitrogen base residues present in DNA.

(a) Write the Haworth structure of sucrose.
(b) Sucrose is a non-reducing sugar. Why?

a) i) Name the water insoluble component of starch.
ii) Mention one water soluble vitamin.
iii) Is Lysine an essential or non-essential amino acid?
b) Write the structure of Maltose.

(a) What is fermentation? Give one example.
(b) Write the balanced chemical equations of the reactions taking place in the manufacture of ethyl alcohol from sugar.

What are 'nucleic acids'?
Define complex lipids. Mention any 'two' functions of lipids.

State whether the following statements are true or false :
(i) The general formula of alkanes is $${C}_{n}{H}_{2n+2}$$.
(ii) Carbohydrates are body building nutrients.

Write the functions of the following vitamins:
(i) Vitamin A (ii) Vitamin D
(iii) Vitamin E (iv) Vitamin K

Cane Sugar, Glucose and Starch are Carbohydrates.
(a) Represent the structure of Glucose.
(b) Write a method to prepare Glucose from Starch. Write the chemical equation of the reaction.
(c) Suggest any two uses of Carbohydrates.

(a) What are enzymes ?
(b)Discuss the mechanism of enzyme action.

Short / Long answer type questions.
What happens to the starchy part of a meal from the time it is eaten till it is made available to body tissues?

Differentiate between.
Enzymes and inorganic catalysts

Classify the following into monosaccharides,oligosaccharides and polysaccharides.
(1) starch, (2) glucose, (3) stachyose, (4) maltose, (5) raffinose,
(6) cellulose, (7)sucrose, (8) lactose.

Fill in the blanks:
Polymer of nucleotides are called ......

Fill in the blanks:
The formula $$C_{x}(H_{2}O)_{y}$$ can be assigned to $$...........$$

Give one example of each of the following
Reducing sugar, Non-reducing sugar

Classifying the following into monosaccharides, disacharides and polysaccharides
Ribose,glycogen,maltose,deoxyribose,lactose,fructose,glucose,cane-sugar ,starch cellulose

Explain the observed $${K}_{b}$$ order:
$$E{t}_{2}NH> E{t}_{3}N> Et{NH}_{2}$$ in aqueous solution

Unscramble the following word related to components of food.

BOCATRADHYER

Carbohydrates and _-provide___ to our body.

The compound in food materials are given, Filling the missing ones
a)Carbohydrates - Carbon, Hydrogen
b)Protein - Carbon, Hydrogen, oxygen
c)Fats - Carbon, Hydrogen

Write short notes on the following:
(a) Enzyme specificity (b) Enzyme inhibition

Answer the following questions:

Write Haworth projection formula of $$\alpha -D-(+)-$$glycopyranose.
Define hormones.

Define the following terms with a suitable example:
Polysaccharides

Fill in the blanks:
A disaccharide consists of two ..... joined by ..... bonds.

Fill in the blanks:
A polysaccharide is a polymer of ..........

Fill in the blanks:
Protein is a polymer of......