Class 11 Medical Biology - Biomolecules

Respiration is an anabolic and catabolic both. Justify the statement by giving example.

The breaking of the C-C bonds of complex compounds through oxidation within the cells, leading to the release of a considerable amount of energy is called as respiration. As carbon-carbon covalent bonds are broken, it is a catabolic process. Respiration involves the synthesis of energy in form of ATP. The synthesis of ATP leads to the formation of several covalent linkages of phosphates. There is synthesis which is included in the anabolic processes.

Anabolic reactions are always endergonic reactions. Justify this statement with an example.

$$\large\textbf{Solution}$$

$$\bullet$$ $$\textbf{Anabolic reactions}$$ are the processes where small organic molecules are being used to produce larger molecules.

$$\bullet$$ Anabolic reactions can be of 2 types-

1) Endergonic

2) Exergonic

$$\textbf{Example- Proteins and enzymes interaction}$$

$$\bullet$$ Proteins are macromolecules which are said to be building blocks of the body

$$\bullet$$ Enzymes have a lock-key mechanism that have specific substrates for specific enzymes.

Growth can be termed as an anabolic and catabolic process both. Justify the statement with a valid reason.

Growth is the process in which the number of cells in the organism increases. During cell division, there is breaking down as well as the synthesis of many compounds. The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules in which the energy is released due to the breaking of the bonds of the larger complex molecules. The anabolic processes are the reactions in which the smaller organic molecules are used for the production of the large complex molecules in which energy is added. So, growth includes catabolic as well as the anabolic process.

Catabolic reactions are exergonic reactions. Justify the statement with reason.

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. The energy is released due to breaking of the bonds in the ATP molecule to produce ADP or AMP.

Why anabolic reactions are endergonic reactions?

The anabolic processes are the reactions in which the smaller organic molecules are used for the production of the large complex molecules. The energy is added to the smaller amino acids which react to form the linear chain of large proteins. This is an example of the endergonic reaction where energy is required to initiate the reaction. The phosphate group is added to the AMP and ADP molecules to form ATP. There is energy stored in this large molecules.

Give an example for catalytic proteins.

Catalytic protein:- catalytic protein increases in the rate of a chemical reaction by the active site of a protein.

The enzyme is a catalytic protein.

Example= Catalase.

Why are catabolic reactions always exergonic reactions?

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. Digestion is the catabolic process in which the larger molecules are broken down into simpler ones releasing energy.

Digestion is a catabolic process. Justify the statement with reason.

The catabolic processes are the reactions in which the large complex molecules are broken down to form the smaller molecules. The process is an exergonic process in which the energy is released due to the breaking of the bonds of the larger complex molecules. Intracellular digestion refers to the breaking of the larger molecules during internal respiration in the mitochondria. Intercellular digestion is the processes in which the molecules are broken down and then absorbed.

Man is an example of _________ organism.

Man is an example of complex homo sapiens organism

What are the functions of proteins?

Proteins are the most important nutrient in our food.

Functions of proteins:

(i) The major structural component of cells which is responsible for the building and repair of body tissues.

(ii) Proteins do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs.

(iii) It helps our body to fight against infections.

(iv) It helps in the formation of nails, hair and muscles.

Mention the three differences between a living cell and a brick in a wall.

Listed below are the differences between a living cell and a brick in a wall.

$$\begin{array}{|l|l|}\hline {\text { Living cell }} & {\text { Brick }} \\\hline \text { The living structure is non-rigid } & \text { Living structure is rigid } \\\hline \text { Contains cellulose chiefly } & \text { Contains soil primarily } \\\hline \begin{array}{l}\text { It is functional in nature, performs critical } \\\text { finctions pertaining to life processes }\end{array} & \text { Non-functional } \\\hline \text { Generously permeable } & \text { Impermeable } \\\hline\end{array}$$

What is plasma?

Hint: Plasma is the fourth state of matter.

Explanation :

Plasma is considered as a gas which has been provided with enough energy such that some of its electrons can break and become free but still travel with nucleus.
A spark in a gas can create plasma.
It has a lot of industrial utility.

Can you attempt building models of biomolecules using commercially available models (ball and stick models).

Yes. Provided balls of different sizes and colours are available.

Who conducted in vitro synthesis of DNA ?

A. Kornberg in 1959

Choose the ODD one out of the following terms given and name the CATEGORY to which the others belong:
Phosphate, RNA, Sugar, Nitrogenous base.

A nucleotide is the basic structural unit and building block for nucleic acids. It is composed of three subunit molecules: a five- carbon sugar (ribose or deoxyribose), a nitrogenous base and one phosphate group.

RNA stands for ribonucleic acid and is a nucleotide.

So, the answer is RNA.

Active transport is the one in which the ions outside the roots move in with expenditure of energy................

Active transport is the one in which the ions outside the roots move in with expenditure of energy from the region of their lower concentration outside to the region of their higher concentration inside.

Some enzymes are named after the reaction, where they are used. What name is given to the class of enzymes which catalyze the oxidation of one substrate with simultaneous reduction of another substrate?

Oxidoreductase is a class of enzymes that catalyze the oxidation of one substrate with a simultaneous reduction of another substrate.

Nucleic acids exhibit secondary structure, justify with example.

We know that when a long chain of polymer is arranged as helix: the helix is called secondary structure. We also know that DNA is a double helix structure. Even RNA forms a single helix. Roth DNA and RNA are nucleic acids. Since they show helices; they exhibit secondary structure

Match the tissues/molecules mentioned in the list I with the options mentioned in the list II and select the correct option from the given codes.

Cell wall	Cellulase
RNA	Ribonuclease
Histone	Protease
Pectin	Pectinase

The list is of a tissue or molecule and their corresponding degrading enzymes. The correct pairs are shown in the table.

List three main differences between DNA and RNA ?

DNA (De-oxyribonucleic acid )	RNA (Riboucleic acid)
DNA usually exists in the double stranded form	RNA predominantly exists in the single-stranded form
The monomeric unit: nucleotide of DNA has Deoxy ribose sugar	It is ribose sugar in RNA
In DNA- Purines; Adenine and Guanine (A and G), Pyrimidines; Thymidine and Cytosine (T and C)	In RNA - Purines; Adenine and Guanine (A and G), Pyrimidines; Uracil and Cytosine (U and C)

Only .......... amino acids are present in the proteins

Only L- amino acids are present in the proteins

What are the structural units of nucleic acids?

Nucleotides are the structural units of nucleic acids.

Name a molecule acting as energy currency in organisms

AenosineTriPhosphate is an energy currency in organisms.

Differentiate between the following pairs on the basis of what is mentioned in brackets:
NADP and ATP [Expand the abbreviation].

Full form of NADP is Nicotineamide adenine dinucleotide phosphate.

Full form of ATP is Adenosine tri phosphate.

Define metabolic waste.

Metabolic wastes are those products which are produced in metabolic reactions, and not useful to the organism.

Observe the given figure and answer the questions given below.
Which fraction would probably show the greatest amount of hydrolytic enzyme activity? Give a reason for your answer.

The fraction C is centrifuged at the speed of 15,000 g. The lysosomes gets separated when centrifugation is carried out at the speed of 10,000 - 20,000 g for 15 - 20 minutes. The lysosomes are called as suicidal bags. These organelles contain hydrolytic enzymes like proteases, lyases, hydrolyases, oxidases, glycosidases, etc. These enzymes helps in destruction of various toxic compounds as well as the foreign particles or microorganisms which enter the cell. The enzymes can be used for the breakdown of all kinds of biomolecules. The enzymes can also help in the destruction and clearance of the cellular debris. So, the fraction C will show maximum hydrolytic activity.

Observe the given figure and answer the questions given below.
Which fraction would you expect to produce most radioactively-labelled protein if labelled amino acids were added? Give a reason for your answer.

The fraction E was centrifuged at the speed of 300,000 g. The ribosomes are separated free from the other organelles when the fraction is centrifuged at the speed of 150,000 - 300,000 g for 60 minutes. The ribosomes are formed by the assembly of many rRNA proteins. These are the site of protein synthesis. The tRNA and the mRNA play an important role in protein synthesis. The ribosome move along the mRNA molecule. The ribosome catalyze the assembly of the amino acids to form the protein molecules. These ribosomes also attach to the tRNA and other proteins which are involved in protein synthesis. So, the radio-labelled amino acids will be transformed to radio-labelled proteins in the fraction E.

"Chlorophyll contains Mg and chlorine."
Answer whether the above statement is true or false. If true enter 1, else 0.

Chlorophyll contains Mg only as

"Chlorophyll is an organometallic compound."
Answer whether the above statement is true or false.
If true enter 1, else enter 0.

Chlorophyll is an organometallic compound. It contains Mg metal at the centre of the porphyrin ring.

Name two structural polysaccharides which are found in fungi.

Structural polysaccharides found in fungi are chitin and cellulose.
(i) Cellulose. It occurs in a few fungi either alone (e.g., Phytophthora) or alongwith chitin. Cellulose is a homopolysaccharide of B 1- 4 glucose residues.
(ii) Chitin (Fugus cellulose). In most fungi the structural polysaccharide of wall is chitin or fungus cellulose. It is a heteropolysaccharide of acetyl glucosamine residues.

What is metabolism and what is its purpose?

Metabolism is a term that is used to describe all chemical reactions involved in maintaining the living state of the cells and the organism. Metabolism can be conveniently divided into two categories:
Catabolism - the breakdown of molecules to obtain energy
Anabolism - the synthesis of all compounds needed by the cells
Metabolism is closely linked to nutrition and the availability of nutrients. Bioenergetics is a term that describes the biochemical or metabolic pathways by which the cell ultimately obtains energy. Energy formation is one of the vital components of metabolism.

What are macromolecules? Give examples of it.

Macromolecules are large complex molecules present in the colloidal state in the intercellular fluid. They are formed by the condensation of low molecular weight micromolecules and hence, are polymeric in nature.

Polysaccharides, proteins, and nucleic acids are common examples of macromolecules.

Amino acids contain the elements carbon, hydrogen, oxygen and _________.

Amino acids contain the elements carbon, hydrogen, oxygen and nitrogen. There are amino groups in the basic structure of every amino acid.

Write differences between primary metabolism and secondary metabolism.

Primary and secondary metabolism

Primary metabolism - is a process that occurs in all living cell and is essential for the survival of the cell

Secondary metabolism - It is a parallel or a derived process from primary metabolism. Not necessary for the survival of the cell. It need not be the same in all cells nor in all organisms.

Example: Resin, tannins, essential oils etc synthesized by certain species of plants

What are enzymes ?Give two examples with uses.

Enzymes are complicated organic molecules which are produced by living cells and are also called biological catalysts. They are complex nitrogenous molecules, unlike energanic catalysts, they take part in the reaction and get destroyed.
Factors affecting the activity of catalyst ;
(i) Temperature, (ii) pH, (iii) concentration of enzyme, (iv) concentration of substance, (V) concentration of the product formed.
Functions of Enzymes : Enzymes play a very important role in many biological reactions. They names of some important enzymes and the biochemical reactions catalysed by them are given below :
(1) Role of enzymes in the process of digestion : Enzymes play an important role in digestionresulting in breakdown of macro molecules into simple molecules.
(2) Industrial application : Enzymes play an important role in many industrial processes such as manufacture of ethanol from sugar or starch, manufacture of acetic acid, manufacture of cheese, leather, tanning etc.

What is the action of ligases?

Ligases can join any DNA fragments with 'blunt' ends. They can also join DNA fragments with 'sticky' ends, but only if the nucleotides on the strands are complementary.

Write any four supplication of enzymes?

Enzymes used to treat disorders: Enzymes are used in three cases here

a) To break the internal blood clots.

b) To dissolve the hardening of walls of blood vessels.

c) To dissolve the wound swelling to promote healing.

Enzymes used to assist metabolism: In old or geriatric patients, the digestive capacity is low due to insufficient secretion of digestive enzymes. Hence their digestive system cannot digest food materials efficiently. In such cases they can experience malnutrition, constipation, bloating etc. To aid digestion, enzymes like Papain are administered orally after food for easier digestion.
Enzymes used to assist drug delivery: Some drugs need to penetrate deeper tissues for better action. For this some enzymes are used along with drugs in intra-muscular injection forms to help proper penetration of tissues. One of the such enzyme is Hyaluronidase.
This is a natural human enzyme present in human sperm to help sperm penetrate uterine tissue and fertilize with ova. Here the same enzyme is manufactured by rDNA technology and administered along with drugs to enable efficient drug delivery to the target site.

Explain the major classes of enzymes.

Classes of enzymes are:-

Oxidoreductases =Dehydrogenase oxidase, Peroxidase reductase
Transferases = C-transferase, Glycocyltransferases
Hydrolases = Esterase, Peptidase
Lyases = C-C-lysase, C-O-lysase
Isomerases = Epimerase
Ligases = C-C-ligase, C-O-ligase.

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

Proteins, carbohydrates and lipids are made from three basic molecules: carbon, hydrogen and oxygen. However, all proteins contain an element not found in carbohydrates and lipids is nitrogen. Nitrogen which is present in all amino acids (the building blocks that make up the protein chains).

Name two scientists who proved experimentally that DNA is the genetic material.

Frederick Griffith and Alfred Hershey and Martha Chase proved in different experiments that DNA is the genetic material.

What is the function of ATP in cell metabolism ? Explain with the aid of diagram, how its structure makes it possible.

ATP or Adenosine triphosphate is the energy currency of the cell. It is a molecule with high-energy unstable bonds. The huge amount of energy released as a result of the hydrolytic removal of the phosphate groups from the ATP molecule is used for the various metabolic reactions inside the cells.

Which is the principal mineral cation in the extracellular fluid.

Electrolytes are substances that dissociate in solution and have the ability to conduct an electrical current. These substances are located in the extracellular and intracellular fluid. Within the extracellular fluid, the major cation is sodium and the major anion is chloride. The major cation in the intracellular fluid is potassium. These electrolytes play an important role in maintaining homeostasis.

Describe functions of polysaccharides in living organisms.

Polysaccharides are an important class of biological polymers. Their function in living organisms is usually performed one of two functions: energy storage or structural support. Starch and glycogen are highly compact polymers that are used for energy storage. Cellulose and chitin are linear polymers that are used for structural support in plants and animals, respectively.

Match the following lists

A) Lyases are a class of enzyme that catalyze the breaking of various chemical bonds (carbon-carbon, carbon-oxygen, carbon-nitrogen, etc.) by means other than hydrolysis and oxidation, often forming a new double bonded structure.

B) Ligases are enzymes that catalyze the joining of two molecules by forming a new chemical bond. DNA ligases are enzymes required for the repair, replication and recombination of DNA.

C) Hydrolases are hydrolytic enzymes, biochemical catalysts that use water to cleave chemical bonds, usually dividing a large molecule into two smaller molecules. Hydrolases can be further classified into several subclasses, based upon the bonds they act upon:

(i) ester bonds (esterases: nucleases, phosphodiesterases, lipase, phosphatase)

(ii) sugars (DNA glycosylases, glycoside hydrolase)

(iii) ether bonds

(iv )peptide bonds (Proteases/peptidases)

D) Transferases are enzymes that catalyse the transfer of a specific functional group from a donor molecule, often a coenzyme, to an acceptor molecule.

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

Differentiate between ATP and AIDS based on their abbreviations.

$$\textbf{Solution}$$

$$\bullet$$ ATP:- adenosine triphosphate.

It is organic compound which provides energy to perform various cellular activities.

It is primarily made up of three components ribose sugar, night space and triphosphate.

This is produced during various processes like glycolysis oxidation and TCA cycle.

$$\bullet$$ AIDS: Acquired immunodeficiency syndrome.

It is a viral infection which is caused due to HIV (human immunodeficiency virus).

It is a sexually transmitted disease which weekends the persons immunity.

It can easily transmitted through body fluids such as blood, saliva and sweat.

Name the following :
The compound which stores energy in the cells.

ATP (Adenosine triphosphate) stores energy in the cells.

Atoms\ions needed in very small amounts function mainly as .......... of enzymatic reactions.

Atoms\ions needed in very small amounts function mainly as $$\underline {cofactors}$$

.......... is invariably a component of amino acids, nucleic acids and chlorophylls.

$$\underline {Nitrogen}$$ is invariably a component of amino acids, nucleic acids and chlorophyll.

Name the enzyme which possibly acts as an ion carrier.

Enzyme phosphokinase is as ion carrier or transfers phosphate ion to a specific compound.

The conversion of Fructose to Fructose-1-phosphate is mediated by enzyme Hexokinase a type of phosphokinase that phosphorylates hexose sugar.

Differentiate between.
Isomerases and transferases

Isomerases catalyse the reaction in which substrate is converted into its positional or optical isomer by intramolecular rearrangement. Whereas, transferases bring about transfer of a functional group other than hydrogen from one substrate to another.

The induced fit theory for enzyme action was given by..........

The induced fit theory for enzyme action was given by Koshland.

To which chemical group do all enzymes belong?

All the enzymes belong to the category of proteins. Proteins are distinct from carbohydrates, nucleic acids, and lipids and in that, a protein is made of amino acids. these link together to form a three-dimensional type structure.

Value based questions.
Try to explain the following observations
When $$K^+$$ ions are removed from the medium surrounding red blood cells, sodium influx into the cells and potassium efflux increase dramatically.

A $$Na^+/K^+$$ pump operates whereby efflux of $$Na^+$$ is linked to influx of $$K^+$$ without Kt no $$Na^+$$ efflux can occur so $$Na^+$$ accumuulates within the cells by diffusion and $$K^+$$ leaves the cells by diffusion.

Very Short Answer Types :
Name the two types of cell divisions occur in living cells.

Mitosis, and meiosis

What are proteins? Name the bond present in the proteins

Proteins are the nitrogenous organic compounds which are composed of one or more long chains of amino acids that forms enzymes, hormones and structural components of the body. The bond present in the proteins are called peptide bonds.

Explain the process of formation of complex protein?

The process of formation of complex protein:-Protein complex: It is formed when two or more polypeptide chain are interconnected they form non-covalent interaction between two protein. In the process protein complex formation it includes an encounter complex, where protein have specific interaction and take many orientations, they have two types of interaction one is electrostatic interaction and hydrophobic interaction play an important role.T he protein remain soluted during the encounter phase.The protein forms an encounter complex in very extreme care and the encounter state consist of a significant in many different care which implies that there is small energy difference between encounter and productive complex. Therefore, in protein complex, the encounter complex implies the essential part.

Match the following polymers with their possible monomers

The monomers of DNA are called nucleotide. They are made up of a 5-carbon sugar(deoxyribose), a phosphate group and a nitrogenous base bound to the sugar
The monomer of protein polymer is an amino acid. Methionine is a dietary essential amino acid that plays unique roles, both in protein structure and in metabolism. Methionine serves as the initiating amino acid in eukaryotic protein synthesis.
The monomer of polysaccharides is monosaccharides. Glucose is a monomer of many polysaccharides like cellulose, glycogen, starch.

The presence of thymine at the place of uracil also confers additional stability to DNA. How?

Thymine at the place of uracil confers to additional stability because thymine has greater resistance to photochemical mutation, making the genetic material more stable. It also forms hydrogen bonds with adenine giving it extra stability.

Why are proteins considered to be heteropolymers?

A polymer is a giant molecule made up of many smaller molecules called

monomers. If all the monomers are identical the polymer is a homopolymer.

For example starch is made solely of glucose molecules so starch is a homopolymer. If the monomers are not identical the polymer is heteropolymer . Proteins are made up of up to 20 different amino acids, so proteins are heteropolymers.

Why is plasma membrane also called as selectively permeable membrane?

Plasma Membrane is also called as selectively permeable membrane due to, Plasma membrane allows some material to pass through it while on the same time it blocks other material from entering through it.

In other words, it can select the materials, which enters the cell, Hence it is called a Selectively Permeable Membrane.

What are the most common constituents of organic compounds found in organisms?

The most common constituents of organic compounds found in organisms are protein, carbohydrate, lipid and nucleic acid.

Give one example for a complex polysaccharide having amino sugars.

Amino sugars are components of structural polysaccharides and of glycosphingolipids of membranes. N-Acetylmuramic acid, a constituent of a bacterial cell wall polysaccharide, has a lactyl side chain linked to C3 of glucosamine through an ether linkage. The polysaccharide is a polymer of alternating N-acetylmuramic acid and N-acetylglucosamine residues linked in a β(1 → 4) glycosidic bond. Lysozyme (also called muramidase) catalyzes the hydrolysis of these bonds. The polysaccharide chains are cross-linked through short peptide chains, and the overall structure is known as a peptidoglycan. N-Acetylneuraminic acid, known as sialic acid, is a derivative of a ketonanose. It occurs in the oligosaccharide side chains ofsome glycoproteins and in gangliosides, both of which are constituents of cell membranes

Condition A : Substrate X, specific for Enzyme E1, can be replaced by molecule C (which blocks the enzyme), if C is present in more concentration.

Condition B : Substrate Y can never bind to Enzyme E2, if molecule D binds to the enzyme.

a. At which sites are molecules C and D binding to the enzyme E1 and E2 respectivbely?
b. Which kind of inhibitors are C and D?
c. Describe another factor which can effect an enzyme's activity.

(a) The part of the enzyme where the substrate binds is called the active site(since that’s where the catalytic “action” happens).

(b) C is a Competitive inhibitor as it is competing with the substrate while D is a non-competitive inhibitor as it does not allow the substrate to bind the site at all.

What are proteins? Describe the different biological function of proteins.

Proteins are the building blocks of the body. It is formed by linking of chain of amino acid by the peptide bond.

The biological functions of proteins are:

1) Enzymes are proteins which catalyse the biochemical reactions.

2) Proteins like actin and myosin help in the contraction of muscles.

3) Several hormones are peptides and proteins. They play an important role in the regulation of metabolic reactions.

4) Albumin is a plasma protein which maintains the colloid osmotic pressure of plasma and transport materials.

5) Fibrinogen is a plasma protein which helps in blood clotting.

Who discovered nucleic acid? What was it called then?

Friedrich Miescher discovered nucleic acids in 1869.
They were called nuclein.
Richard Altmann in 1889 discovered that nuclein has acidic properties and it was named as nucleic acid.

Define : Inorganic inclusions of cell

Ergastic substances or cell inclusions are the products of cell metabolism, appearing and disappearing at various stages of cell’s life-cycle. They may be present in soluble or insoluble state and may be organic or inorganic in nature.

The accumulation of inorganic materials within the plant and their cells mostly takes place in the form of calcium salts or anhydrous silicate salts.

What is amylose?

Amylose is a polysaccharide which is a major constituent in starch.
It is formed by the alpha 1,4 linkage between glucose molecules.
It is important in plant energy storage.
It is the preferred starch for storage in plants which makes up about 30% of the stored starch in plants.
It is less readily digested than amylopectin, however, because it's more linear than amylopectin, it takes up less space.
The enzyme amylase breaks down amylose into starch.

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Write a short note on metabolism.

Metabolism is a series of enzyme-catalysed biochemical reactions taking place in living cells.
It is of following types:

1) Anabolism- is the metabolic pathway in which compound nutrient molecules are synthesized from simpler forms. For example, the production of glucose from carbon dioxide and water (photosynthesis).

2) Catabolism- is a metabolism pathway in which larger nutrient molecules are broken down into simpler forms. For example, glycolysis i.e the breakdown of glucose to produce energy.

When anabolism and catabolism operate together the process is called amphibolism. For example, the Krebs cycle.

What are biomolecules? How they are useful in day to day life?

Bio molecules are the organic molecules formed in the cells of organisms, these includes proteins, carbohydrates and nucleic acid, which are the major class of the biomolecules.

Bio molecules have wide range of structures and sizes perform vast variety of functions in day today life. No organisms exist without the bio molecules as they help in carrying out basic functions of body.

The four most important and major biomolecules are protein, lipids, carbohydrates and nucleic acid.

Carbohydrates - These are made up of carbon, hydrogen and oxygen, and are major source of energy. These are the long chains of sugars. Most abundant bio molecule on the earth.

Lipids - These are considered as building blocks of membranes as they separate cells from environment and compartmentalize the interior of cell, which further give rise to cell organelles like mitochondria and nucleus. The lipids are considered as stored energy material and act as chemical messenger. Lipids esters of fatty acids, the fatty acids may be saturated or unsaturated. Lipids have polar head and non-polar tail.

Proteins - These are heteroploymer made up of one or more long chain of amino acids, these perform a vast array functions which includes responding to the stimuli, DNA replication and catalyzing metabolic reactions and also provides structure to the organisms. It helps in repairing of tissue , hormone and other chemical messenger.

Nucleic acid - These are made up of polymer of nucleotide and have hetero cyclic ring. These contains pentose sugar, nitrogen bases and phosphate group. Nucleic acid includes DNA and RNA

Usually DNA stores genetic information of the organisms, while RNA helps in the synthesis of protein by transcription and translation.

Fill in the table basis of your observations in field trip.
S. No. Name of the plant Secondary metabolites Uses
A. Neem
B. Datura

S.No.	Name of the plant	Secondary metabolites	Uses
A.	Neem	Nimbin	Antiseptic
B.	Datura	Scopolamine	Prevents nausea and vomiting

Explain factor effecting enzyme activity.

Factors affecting enzyme activity are

Temperature: The temperature at which an enzyme shows its highest activity is called optimum temperature. Enzyme activity decreases above and below 37 degree Celsius. Enzyme becomes inactive below minimum temperature and beyond maximum temperature. High temperature destroys enzymes by causing their denaturation. This occurs at 50 degree celcius or so.

pH: Every enzyme has an optimum pH when it is most effective. If the pH is lower or higher than the optimal pH, the enzyme activity decreases until it stops working.

Enzyme Concentration: The rate of a biochemical reaction rises with the increase in enzyme concentration up to a point called limiting or saturation point. Beyond this, increase in enzyme concentration has little effect.

Product concentration: If the products are allowed to remain in the area of the reaction, the rate of forward reaction will fall. Reverse reaction can also occur.

Substrate concentration: Increase in substrate concentration increases the rate of reaction. The enzyme molecules are saturated with substrate.The excess substrate molecules cannot react until the substrate already bound to the enzymes has reacted and been released.

Activators: They increase activity of enzymes, function as cofactors and convert pro enzymes to enzyme state. HCl of digestive juice changes pro enzyme pepsinogen to enzyme pepsin.

The energy currency of the cell is _________.

The energy currency of the cell is ATP. Energy is obtained from ATP to the cell to do work.

What are biomolecules?

$$\bf{Explanation:}$$

Biomolecules are the building blocks of life and perform important functions in living organisms.

Carbohydrates, Proteins, Lipids, and Nucleic Acids are the best examples of the $$4$$ biomolecules found in living organisms.

What forms the backbone of a polynucleotide strand of a nucleic acid?

A chain of nucleotides is called polynucleotide strand. In the polynucleotide strand, the adjacent nucleotides are linked with one another by phosphodiester bonds. Phosphodiester bonds are formed between a phosphate molecule and two sugars. So, sugars and nitrogen bases act as back bone to the polynucleotide chain.

What is N-glycosidic linkage

Glycosidic bonds are covalent chemical bonds that hold together a glycoside. A glycoside is simply a ring-shaped sugar molecule that is attached to another molecule. A glycosidic bond forms by a condensation reaction, which means that one water molecule is produced during formation of a glycoside. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside. N-glycosidic bonds, have the glycosidic bond oxygen replaced with nitrogen. Substances containing N-glycosidic bonds are also known as glycosylamines.

What is the role of enzyme Taq polymerase in gene amplification ?

Taq polymerase is an enzyme that copies DNA. It is isolated from a heat-loving bacterium that is naturally found in hot springs, so the enzyme doesn't break down at the high temperatures necessary for copying DNA using a polymerase chain reaction.

-S-S- bonds are found in which structure of proteins.

-S-S- is called disulphide bond which is found in the tertiary structure of the protein.
These disulphide bonds are strong, covalent bonds that help stabilize the structure of proteins and prevent them from becoming denatured in the extracellular environment.
A covalent bond is formed between two sulfur atoms on the two cysteine amino acid in the peptide chain.

Out of respiration and photosynthesis which is anabolic and which is catabolic process. Why?

A catabolic process is a process by which complex compounds are broken down into simpler components or molecules and releases energy.
Whereas, the anabolic process creates complex molecules broken down in catabolism by utilizing energy and these molecules remain in the organism to be used again.
Photosynthesis is an anabolic process as it combines carbon dioxide and water in the presence of solar energy to form a complex substance called glucose in the leaves.
Respiration is a catabolic process as it breaks down complex molecules into simpler ones with release of energy in the form of ATP molecule.

Briefly describe the factors affecting enzyme activity.

Enzyme activity can be affected by a variety of factors, such as temperature, pH, and substrate concentration.
Temperature: Increase in temperature generally speeds up a reaction, and decrease in temperature slows down a reaction. And at extreme high temperatures, enzyme lose its shape (denature) and becomes functionless.
pH: Each enzyme has an optimum pH range. Changing the pH outside of this range will slow enzyme activity. Extreme pH values can cause enzymes to denature.
Substrate concentration: Increasing substrate concentration also increases the rate of reaction, after all of the enzymes have bound, any substrate increase will have no effect on the rate of reaction.

Explain the process of formation of complex proteins.

Amino acid joins together to for long polypeptide chains, these chains join together to form a complex protein structure. These are basically called Quaternary structures of proteins.

In Quaternary structures, proteins are attached with each other via non-covalent interactions and shereochemical arrangements of individual protein molecules.

Examples of Quaternary proteins are collagen protein, hemoglobin protein and many more.

What are catabolic and anabolic processes?

Catabolic processes: In catabolic processes, complex compounds are disintegrated whereby simple compounds are produced. The energy produced during these processes is utilised in the accomplishment of various biological processes.
Anabolic processes: In anabolic processes, complex compounds are produced by the fusion or reaction of simple compounds. These complex compounds are essential for the organisation and formation of the various structures of cells.

What is the source of information for making proteins in the cell?

The source of information for making proteins is the DNA in the cells. The part of DNA which codes for a particular protein is the gene for that protein.

Define metabolism.

All the biological reactions that convert ingested food into forms required by the body and into energy ,togetherly, the process is referred to as metabolism.
Metabolism is of two types, viz, anabolism and catabolism.

DNA and RNA are the two important nucleic acids present in our body. The study of DNA and RNA is very useful in research bodies.
A. What are the main structural differences between DNA and RNA?
B. What are nucleotides? Name the three components of nucleotides.
C. Mention the applications of studying DNA in different fields.

A. The main structural differences between DNA and RNA are as follows:

RNA is single-stranded while DNA is double-stranded.
RNA contains uracil while DNA contains thymine.
RNA has the sugar ribose while DNA has the sugar deoxyribose.

B. A nucleotide is the basic building block of nucleic acids. It includes a heterocyclic compound, monosaccharide, and phosphoric acid or phosphate.

C. DNA analysis can be used in the study of hereditary diseases, in forensic medicine, and for the detection of pathogens.

Explain in detail, classification of enzymes.

International Union of Biochemistry (IUB) suggested the use of all the reactions and equations for the purpose of classification of enzymes and the Enzyme commission has classified all enzymes into six main divisions (categories).
1. Oxidoreductases
2. Transferases.
3. Hydrolases
4. Lyases
5. Isomerases
6. Ligases or Synthetases.
The six division are as follows:
1. Oxidoreductases:
All those enzymes which catalyze oxidation-reduction reactions are included in this category. They catalyze the removal or addition of hydrogen, oxygen, or electrons from the substrate or to the substrate and thus bring about oxidation or reduction.
Note: On the basis of their activity these can be a divide into three subgroups:
(a) Oxidases: These bring about oxidation of the substrate by transferring hydrogen from the substrate molecule to oxygen.
Example: Cytochrome oxidase, Ascorbic acid oxidase, etc.
$$ A.H_{2}O + \frac{1}{2} O_{2} \rightleftharpoons A + H_{2}O $$
$$ A.H_{2}O + O_{2} \rightleftharpoons A + H_{2}O_{2} (A=Substrate) $$
(b) Dehydrogenases:
These enzymes bring about oxidation of substrate molecule by removal of hydrogen from the substrate as follows:
Example - Lactate dehydrogenase, Alcohol dehydrogenase.
$$ A.H_{2} \rightleftharpoons A + 2H^{+} $$
(c)Reductases: These enzymes cause the addition of hydrogen or electron to the substrate and removal of Oxygen.
$$ NO_{3}^{-} + NAD H_{2} \rightleftharpoons NO_{2}^{-} + NAD + H_{2}O $$
2. Transferases:
These enzymes catalyze the transfer of a group (amino, phosphate, methyl, ketone, etc.) from one molecule to another molecule.
Example: Trans phosphatase, Transaminase.
3. Hydrolases:
These enzymes catalyze the addition or removal of water. They hydrolyse a variety of compounds and generally bring about cleavage of the substrate. This group includes digestive enzymes. Which breakdown macromolecules into smaller molecules.
Example: Carbohydrase, Amylase, Nuclease, Esterase, etc.
Most hydrolytic reactions are reversible. These types of enzymes may also condense small molecules to form macromolecules. In such reactions, the water molecule is released. Example: Fumarase, Enolase, etc.
4. Lyases:
These enzymes catalyze the removal of a group from their substrate molecule by breaking a special type of covalent bond without hydrolysis.
Example: Aldolase.
5. Isomerases:
These enzymes catalyze intramolecular reorganisation in the substrate molecule and convert the substrate into its isomer.
Example: Phosphohexoisomerase.-
6. Ligases or Synthetases:
These enzymes catalyze such reactions in which two compounds are linked together by forming covalent bonds between the two.
Example: Pyruvate carboxylase, Citrate synthetase.

What are the biological functions of DNA and RNA? Do proteins affect the functioning of nucleic acids? Explain.

DNA stores genetic information as a codon and transfers the genetic information into RNA.
RNA codes for amino acids (protein) that carry out cell functions.
The proteins affect the functioning of nucleic acids by binding with DNA or RNA which controls the gene expression in both the processes of RNA synthesis (transcription) and protein synthesis (translation).

Can you attempt building models of biomolecules using commercially available atomic models (Ball and Stick models).

Ball and stick models are 3-D molecular models that can be used to describe the structure of biomolecules.

In ball and stick model, the atoms are represented as balls whereas the bonds that hold the atoms are represented by the sticks. Double and triple bonds are represented by springs that form curved connections between the balls. The size and colour of various atoms are different and are depicted by the relative size of the balls. It is the most fundamental and common model of representing biomolecular structures.

In the above ball and stick model of D-glucose, the oxygen atoms are represented by red balls, hydrogen atoms by blue balls, while carbon atoms are represented by grey balls.

Find out and make a list of proteins used as therapeutic agents. Find other applications of proteins (e.g., cosmetics, etc.)

Proteins used as therapeutic agents are as follows :

1. Thrombin and fibrinogen – They help in blood clotting.

2. Antigen (antibody) – It helps in blood transfusion.

3. Insulin – It helps in maintaining blood glucose level in the body.

4. Renin – It helps in osmoregulation.

Proteins are also commonly used in the manufacture of cosmetics, toxins, and as biological buffers.

What is ribozyme?

Explanation:

A ribozyme is an RNA molecule with a well-defined tertiary structure that enables it to act like a protein enzyme in catalyzing biochemical and metabolic reactions within a cell.
These RNA molecules are enzymes that are not composed of proteins.
Ribozymes function as part of the large subunit ribosomal RNA to link amino acids during protein synthesis.

Find out a qualitative test for proteins, fats and oils, amino acids and test any fruit juice, saliva, sweat and urine for them.

Test for protein: Biuret’s test- If Biuret’s reagent is added to the protein, then the colour of the reagent changes from light blue to purple.

Test for fats and oils: Grease or solubility test- This is a simple test which involves the rubbing of the given sample on cloth or paper. The appearance of a translucent spot shows the presence of fats or oils.

Test for amino acid: Ninhydrin test- If Ninhydrin reagent is added to the solution, then the colourless solution changes to pink, blue, or purple, depending on the amino acid.

Substance	Biuret's Test	Grease or Solubility Test	Ninhydrin Test
Fruit Juice	Colour changes from light blue to purple. So, it shows the presence of proteins.	No translucent spot. The absence of fats or oils.	Colour changes to pink, blue or purple colour. So, it shows the presence of amino acids.
Saliva	Colour changes from light blue to purple. Presence of proteins.	No transulent spot. The absence of oil.	Colourless solution changes to pink, blue or purple. Presence of amino acids.
Sweat	No colour change. The absence of proteins.	Oily appearance. Presence of fats or oils.	No colour change remains colourless. The absence of amino acids.
Urine	Colour changes from light blue to purple. Presence of proteins.	A Little bit of oily appearance. Fats or oils may or may not present.	Colourless solution changes to pink, blue or purple colour. Presence of amino acids.

How does the substrate concentration affect the velocity of enzyme reaction?

Enzymes are proteins that speed up the rate of a chemical reaction. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. The rate of a chemical reaction is affected by the total number of enzymes as well as the concentration of substrates. The rate of a chemical reaction increases as the substrate concentration increases. Enzymes can greatly speed up the rate of a reaction, and thus velocity also increases. However, enzymes become saturated when the substrate concentration is high.

Image result for substrate concentration and velocity of enzyme reaction

List the major biomolecules which make up the cell.

Proteins, lipids and carbohydrates are the major biomolecules which make up the cell. Proteins have various functions, such as, structural function (serving as the membrane exoskeleton together with lipids), transport function (they help to transport elements from one side of the membrane to the other) and signalling function (depending on which proteins the cell has in its membrane it is perceived differently by other cells and microorganisms). Lipid function as storing energy, signalling and acting as structural components of cell membranes. The role of carbohydrates is to provide energy, as they are the body's main source of fuel, needed for physical activity, brain function and operation of the organs. All the cells and tissues in the body need carbohydrates and they are also important for intestinal health and waste elimination.

What does an enzyme do in terms of energy requirement of a reaction? What would happen if the enzyme did not play this role?

Enzyme is a protein that accelerates the rate of reactions. It catalyzes the biochemical reaction by lowering the activation energy, the energy required to start a reaction. If the enzyme did not play its role, the reaction would be not catalyzed and the particular body function is either lost or slows down.

Name the following :
(a) Energy currency of the cell
(b) Oxidative breakdown of carbohydrates to release energy
(c) An organism which respires throughout life anaerobically
(d) A common phase to both aerobic and anaerobic respiration
(e) Aerobic respiration requires
(f) A chemical which removes $$CO_{2}$$ from the air

Name the following

(a) Energy currency of the cell is Adenosine Triphosphate or ATP.

(b) Oxidative breakdown of carbohydrates to release energy is known as cellular respiration.

(d) Glycolysis is a common phase to both aerobic and anaerobic respiration.

(e) Aerobic respiration is the release of energy from glucose which requires oxygen.

(f) Calcium hydroxide solution is used to remove $$CO_2$$ from the air.

Write the full forms of ATP and ADP

ATP is Adenosine triphosphate is an important molecule found in all living things. It is energy currency of the cell. If a cell needs to spend energy to accomplish a task, the ATP molecule splits off one of its three phosphates, becoming ADP (Adenosine diphosphate).

If you study the effect of substrate concentration on an enzymatic reaction, what kind of curve would you obtain?

The rate of chemical reaction increases as there is an increase in substrate concentration. Enzymes become saturated when the substrate concentration is high. If we plot a graph with substrate concentration on X-axis and corresponds velocity in Y-axis. It is observed that as there is an increase in the concentration of the substrate, there is a corresponding increase in the reaction. It forms an arc-shaped curve.
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What are the factors which influence enzyme activity? Discuss them in brief.

The factors which influence enzyme activity are:-

Temperature- Change in temperature effects the enzyme activity, the rise in temperature increases the enzyme activity. The heat enhances the kinetic energy of the molecules which results in more collisions between them.
pH- The efficiency of an enzyme is influenced by the pH of its surrounding. The charge of amino acid changes with the change in pH. When the pH values become high or low, the basic structure of the enzyme changes.
Inhibitors- Those substances which have a tendency to prevent activities of the enzyme. They inhibit the enzyme function in two different ways.
Allosteric factors- There are some enzymes which have one active site or one or more regularly sites called allosteric factors.

Match the terms to these definitions
Cofactor, coenzyme, holoenzyme, apoenzyme, ligases, lyases, transferases, isozymes, zymogens, competitive inhibitor, non-competitive inhibitor, activation energy
..........enzymes which catalyse the linking together of compounds utilising the energy from ATP

The cofactor is a substance whose presence is essential for the activity of an enzyme.

The holoenzyme is an active compound which is formed by the combination of enzyme and coenzyme.

An apoenzyme is an inactive enzyme.

Ligase is an enzyme which brings ligation of DNA and another substrate. Lyases are the enzymes which catalyse the joining of specified molecules.

A transferase is a class of enzyme that intact the transfer of specific functional groups.

Isozymes are those enzymes which differ in from each other and occur in a different number.

Zymogens are the inactive compound which converts into an enzyme when activated by another enzyme.

A competitive inhibitor will block the enzymes active site.

A non-competitive inhibitor will bind the enzyme somewhere other than the active site.

The energy which is absorbed before stating a reaction is called activation energy.

Ligases are the enzymes which catalyze the linking together of compounds utilizing the energy from ATP.

Which enzymes has more affinity towards substrate?

Km is the concentration of substrate which permits the enzyme to achieve half Vmax. An enzyme with a high Km has a low affinity for its substrate and requires a greater concentration of substrate to achieve Vmax and vice versa.

Enzyme a has high km and Enzyme b has low km.

So, “enzyme b has high affinity for its substrate”.

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Why proteins are called biological polymer?

Proteins are the macromolecules which are made from the amino acids when joined together by peptide bonds. They are very essential for life and all the cells are made up of proteins. Amino acids are polymers which are used to build tissues and other components of living organisms. Thus, they are called biological polymers.

Select the correct match of enzymes listed, their site of action, their substrate and optimum $$pH$$
Enzyme Site of action Substrate pH
Amylopsin Pancreas Starch $$7.8$$
Trypsinogen Duodenum Peptones $$6.8$$
Nucleotidase Small intestine Nucleoside $$6.8$$
Carboxypeptidase Small intstine Polypeptide $$7.8$$

Enzyme	Site if action	Substrate	pH
Amylopsin	Duodenum	Starch	6.8
Trypsinogen	Small intestine	Polypeptide	7.8
Nucleotidase	Pancreas	Nucleoside	6.8
Carboxypeptidase	Small intestine	Peptones	7.8

Explain the classification of enzymes.

Enzymes are classified into six classes, which are as follows:

1) Oxidoreductase: These enzymes catalyse oxidation and reduction reactions.

2) Transferase: These enzymes catalyse the transfer of functional groups such as methyl or phosphate group.

3) Hydrolases: These enzymes catalyse the hydrolysis reactions.

4) Ligases: These enzymes catalyse the joining of two molecules by making a bond.

5) Isomerases: These class of enzymes bring about the isomerisation reaction

6) Lyases: Lyases brings about lysis and cleavage of various bonds.

S. No.	Name of the plant	Secondary metabolites	Uses
A.	Neem
B.	Datura

Enzyme	Site of action	Substrate	pH
Amylopsin	Pancreas	Starch	$$7.8$$
Trypsinogen	Duodenum	Peptones	$$6.8$$
Nucleotidase	Small intestine	Nucleoside	$$6.8$$
Carboxypeptidase	Small intstine	Polypeptide	$$7.8$$

Biomolecules - Class 11 Medical Biology - Extra Questions