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CBSE Questions for Class 12 Engineering Chemistry Biomolecules Quiz 9 - MCQExams.com
CBSE
Class 12 Engineering Chemistry
Biomolecules
Quiz 9
Glycogen, a naturally occurring polymer stored in animals is a:
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monosaccharide
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disaccharide
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trisaccharide
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polysaccharide
Explanation
Glycogen is a polysaccharide made up of almost $$2000-200000$$ units of $$\alpha-D$$ glucose, it is a branched structure, there are two types of bonds present in glycogen as the $$\alpha$$ 1-4 glycosidic and $$\alpha$$ 1-6
glycosidic bond.
Glycogen stores in cells of liver and muscles and gives the red color with iodine also it is named as animal starch.
Which of the following compounds is found in abundance in nature?
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Fructose
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Glucose
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Starch
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Cellulose
Explanation
Cellulose is a type of carbohydrate, containing chains of glucose rings. The cell walls, which are responsible for providing support and rigidity to the plants are made of cellulose.
It is also the primary constituent of wood, making it the most abundant organic compound found in nature.
Hence, the correct answer is option $$\text{D}$$.
Which of the following vitamin is insoluble in water and fat both?
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E
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K
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H
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C
Explanation
Vitamin H is insoluble in water and fat both. Vitamin B and C are soluble in water. Vitamin A, D, E, K, and P are soluble in fat.
Which carbohydrate does not have $$C_x(H_2O)_y$$ general formula?
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Melitriose
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Stachyose
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Fructose
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Rhamnose
Explanation
Rhamnose is a carbohydrate which does not have $$C_x(H_2O)_y$$ general formula. The formula of Rhamnose is $$ \displaystyle C_6H_{12}O_5$$
Non-reducing sugar is:
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maltose.
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sucrose.
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lactose.
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None of these.
Explanation
Sucrose is a non-reducing sugar due to the absence of a free aldehyde/ketone group whereas maltose and lactose are both reducing sugars
Which set of terms correctly identifies the carbohydrate shown?
(1) Pentose (2) Pentulose (3) Hexulose (4) Hexose (5) Aldose (6) Ketose (7) Pyranose (8) Furanose
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2,6,8
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2,6,7
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1,5,8
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A set of terms other than these
Explanation
The following Carbohydrate is Pentulose (5 membered ring with ketone as a functional group) , Ketose (Contains ketone as the functional group) and Furanose (5 Membered RIng)
So Option A is the answer
$$NH_2 - \underset{CH_3}{\underset{|}{C}H} - \overset{O}{\overset{||}{C}} - NH - CH_2 - CO_2H$$
Identify the amino acid obtained by hydrolysis of the above compound.
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Glycine
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Alanine
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Both a and b
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None of these
Which of the following pair is $$C_2$$ epimer?
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D-Glucose , D- Maltose
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D- Glucose , D- Mannose
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D- Allose , D- Ribose
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D-Glucose , D- Arabinose
Explanation
D-Mannose differs from D-glucose only at $$2$$-carbon atom .
$$\Rightarrow$$D-Mannose and D-glucose are $$C_{2}$$-epimers.
D-glucose & D-fructose can be differentiated by :
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Fehling solution
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Tollens reagent
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Benedict test
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$$Br_2/H_2O$$
Explanation
$$Br_2/H_2O$$ being a mild oxidising agent can only oxidise aldose to carboxylic acids but cannot oxidise ketose.
As glucose contains aldehyde group it gets oxidised and converted into a carboxylic acid and is differentiate from fructose which has ketone group.
Therefore, the correct option is D.
One cyclic acetal form of D-galactose is shown.
Which atom is the anomeric carbon?
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Atom A
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Atom B
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Atom C
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Atom D
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Atom E
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Atom F
Explanation
Atom $$F$$ is anomeric in cyclic acetal form of $$D$$ galactose as shown in given figure of question.Anomeric carbon is stereo center anomeric carbon is either $$\alpha,\beta$$ depending on position of $$-OH$$ group.If $$-OH$$ group down in cyclic form then $$\alpha$$ else it is $$\beta$$.
Which of the following isomeric sugars is most stable?
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0%
0%
Explanation
We will draw its stable form i.e. chair form. If all the bulky group possess equatorial position then the compound is in stable form.
Some $$-OH$$ group are above the plane and some are below the plane. Thus we will draw accordingly.
Synthesis of each molecule of glucose in photosynthesis involves:
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$$6$$ molecules of ATP
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$$18$$ molecules of ATP
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$$10$$ molecules of ATP
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$$8$$ molecules of ATP
Explanation
The chemical reaction that takes place during photosynthesis is given below:
$$6CO_2+6H_2O \rightarrow C_6H_{12}O_2+6O_2+18ATP+12NADPH$$
Thus, synthesis of each molecule of glucose involves 18 molecules of ATP
Which glycosidic linkage is present in Maltose?
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$$\alpha -D-\left( + \right) -glucose\left( { C }_{ 1 } \right) -O-\left( { C }_{ 4 } \right) -\alpha-D-\left( + \right) -glucose$$
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$$\alpha -D-\left( + \right) -glucose\left( { C }_{ 1 } \right) -O-\left( { C }_{ 2 } \right) -\beta -D-\left( - \right) -glucose$$
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$$\beta -D-\left( + \right) -glucose\left( { C }_{ 1 } \right) -O-\left( { C }_{ 4 } \right)-\beta -D-\left( + \right) -glucose$$
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$$\beta -D-\left( + \right) -glucose\left( { C }_{ 1 } \right) -O-\left( { C }_{ 4 } \right) -\alpha-D-\left( - \right) -glucose$$
The two functional groups present in a typical carbohydrate are :
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$$-CHO$$ and $$-COOH$$
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$$-CO$$ and $$-OH$$
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$$-OH$$ and $$-CHO$$
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$$-OH$$ and $$-COOH$$
Explanation
Carbohydrates are polyhydroxy aldehydes or polyhydroxy ketones OR compounds which give aldehydic as well as ketonic groups on hydrolysis. Therefore the major functional groups are (carbonyl) Aldehyde, Ketone, and hydroxy groups.
Which among the following is not the example of carbohydrate ?
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Glucose
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fractose
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Maltose
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Nylon
Explanation
$$\rightarrow$$ Carbohydrates are important source of instant energy in our body system.
$$\rightarrow$$ Honey has been used as instant source of enrgy in ayurvedic medicines.
$$\rightarrow$$ Carbohydrates are used as storage starch in plants and glycogen
$$\rightarrow$$ carbohydrates are also used in textile industry.
So, the correct answer is NYLON (It is a synthetic polymer)
One mole of each of glucose and fructose require $$x$$ and $$y$$ moles of periodic acid respectively, for oxidation. Hence, $$x/y$$ is
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$$1/1$$
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$$2/1$$
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$$5/4$$
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$$9/4$$
Glucose phosphates formed in photosynthesis are Asymmetrically labeled it is called:
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Warbug's effect
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Pasteur's effect
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Dicken's effect
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Gibb's effect
Explanation
Glucose phosphates formed in the photosynthesis are Asymmetrically labeled it is called Gibb's Effect.
When an apoenzyme is separated from its metal component, its activity is
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Decreased
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Increased
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Lost
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Not affected
Explanation
Enzymes are high molecular protein molecules, conjugated with non-protein cofactors i.e apoenzyme which is composed of amino acids only and a prosthetic group consist of a non- protein groups. Cofactors are mostly metal ions or coenzymes, the binding of the enzyme to a coenzyme forms a holoenzyme which has
the necessary components for the proper functioning of an active enzyme, separation causes decreased in catalytic activity.
So, the correct answer is 'decreased'.
The tightly bound non proteinaceous organic compound is?
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Prosthetic group
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Cofactor
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Apoenzyme
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Holoenzyme
Explanation
A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's activity. Cofactors can be subclassified as either inorganic ions or complex organic molecules called coenzymes, the latter of which is mostly derived from vitamins and other organic essential nutrients in small amounts. A coenzyme that is tightly or even covalently bound is termed a prosthetic group.
So the correct option is 'Prosthetic group'.
A carbohydrate $$X$$ having molecular weight $$180g{mol}^{-1}$$ has one primary alcohol group and four secondary alcoholic groups. It reacts with acetic anhydride to form pentaacetate. The molecular weight of pentaacetate formed is:
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$$180$$
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$$210$$
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$$390$$
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$$42$$
Explanation
X is Glucose.
The Weight of Glucose Pentaacetate formed is 390
Which of the following carbohydrate(s) can be hydrolyzed?
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Fructose
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Sucrose
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Glucose
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Starch
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Maltose
The reagent which may be used to distinguish between cane sugar and glucose solution is
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Molusch's reagent
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Iodine solution
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Baeyer's reagent
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Fehling's solution
The $$\alpha$$- D glucose and $$\beta$$- D glucose differ from each other due to difference in carbon atom with respect to its
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Number of $$OH$$ groups
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Size of hemiacetal ring
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Conformation
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Configuration
Molisch test is answered by
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All carbohydrates
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Sucrose
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Fructose
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Glucose
Explanation
Molisch test
is a
test
for carbohydrate or compounds which can be dehydrated to furfural or furfural derivatives in the presence of the concentrated sulphuric acid .
What is the nature of glucose-glucose linkage in starch that males its so susceptible to acid hydrolysis?
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Starch is hemiacetal
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Starch is acetal
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Starch is polymer
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Starch contain only few molecules of glucose
Number of $$HIO_4$$ molecule required to complete oxidation one mole of glucose is :
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4
0%
5
0%
6
0%
None of these
Which of the following is the monomer of cellulose?
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$$\beta-D$$-glucose
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Amylose
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Amylopectin
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Glycogen
Explanation
Monomer of Cellulose is $$\beta - D- glucose$$.
A dextro-rotatory sugar present in fruits is
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Glucose
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Fructose
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Cellulose
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Starch
Explanation
(A) is the correction option. Natural glucose obtained from fruits is a dextro-rotatory isomer. So, it is denoted as (+) Glucose.
A polypeptide on complete hydrolysis gives three amino acids. How many sequences are possible for that polypeptide?
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1
0%
3
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6
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9
Which of the following is not catalysed by a brush border enzyme?
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Maltose $$ \underrightarrow {Maltase }$$ glucose+ glucose
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Lactose $$ \underrightarrow { Lactase }$$ glucose+galactose
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Starch $$ \underrightarrow { Amylase}$$ Disaccharide
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Nucleotides $$ \underrightarrow { Nucleotidase }$$ Nucleoside
Explanation
Maltase, Lactase, and Nucleotidase are brush-border enzymes that catalyze the final catabolism of metabolites in the small intestine.
So the correct option is C.
Which of the following statements correctly completes the statement?
Except for glycine, which is achiral, all the amino acids present in proteins
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are chiral but racemic
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have the $$L$$ configuration at their $$\alpha $$ carbon
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have the $$R$$ configuration at their $$\alpha $$ carbon
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have the $$S$$ configuration at their $$\alpha $$ carbon
Explanation
Glycerine is the only amino acid which is achiral because it has 2 Hydrogen atoms attached to the alpha carbon.
All the amino acids present in proteins have the L configuration at their $$\alpha$$ carbon.This is because D- Amino Acids are not naturally found in proteins.
So Option b is correct
$${ C }_{ 12 }{ H }_{ 22 }{ O }_{ 11 }\longrightarrow 12C+{ 11H }_{ 2 }{ O }$$ in presence of concentrated $${ H }_{ 2 }{ SO }_{ 4 }$$.
Which of the following is obtained in the above reaction?
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Animal charcoal
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Sugar charcoal
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Coke
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Wood charcoal
The volume of 10 N and 4 N HCl required to make 1 L of 7 N HCl are:
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0.5 L of 10 N HCl and 0.4 L of 4 N HCl
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0.6 L of 10 N HCl and 0.6 L of 4 N HCl
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0.8 L of 10 N HCl and 0.7 L of 4 N HCl
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0.75 L of 10 N HCl and 0.4 L of 4 N HCl
Explanation
The active site of an enzyme is formed by a few of the enzyme's
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Carboxyl groups of the amino acids in $$ {1 }^{ 0 } $$ and $$ {2 }^{ 0 } $$ structure
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Amino groups of the amino acids in $$ {1 }^{ 0 }$$ and $$ {2 }^{ 0 } $$ structure
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R groups of the amino acids in $$ {3 }^{ 0 } $$ structure
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Exposed sulphur bonds in $$ {1 }^{ 0 } $$ and $$ {3 }^{ 0 } $$ structure
Explanation
The active sites of the enzyme are formed by the amino acids which are present in the structure. These are special sites that catalyze reactions with the help of special arrangement of the R groups of amino acids in the tertiary structure.
The interactions taking place between the side chains of amino acids give catalytic activity to the enzyme.
The carboxyl group and the amino group of the proteins help it in folding rather than much activity as an active site.
The primary and secondary structures of proteins usually do not have enzymatic activity and they need to fold in a special tertiary confirmation to become enzymatic.
So the correct answer is ' R groups of the amino acid in 3° structure'.
The two forms of $$D-$$glycopyranose obtained from solution of $$D-$$glucose are known as
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Epimers
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Anomers
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Enantiomers
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Geometrical isomers
Rate of reaction depends upon_________?
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Temperature
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Catalyst
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Concentration
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All of these
Which of the following does not reduce Benedict's solution?
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Sucrose
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Aldehyde
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Glucose
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Fructose
Explanation
Sucrose..
Because Sucrose (table sugar) contains two sugars (fructose and glucose) joined by their glycosidic bond in such a way as to prevent the glucose isomerizing to aldehyde, or the fructose to alpha-hydroxy-ketone form. Sucrose is thus a non-reducing sugar which does not react with Benedict's reagent.
The segment of DNA which acts as the instrumental manual for the synthesis of the protein is:
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ribose
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gene
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nucleoside
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nucleotide
Explanation
A gene is the molecular unit of heredity of a living organism. It is widely accepted by the scientific community as a name given to some stretches of deoxyribonucleic acids (DNA) and ribonucleic acids (RNA) that code for a polypeptide or for an RNA chain that has a function in the organism, though there still are controversies about what plays the role of the genetic material.
Optimum temperature and pH for enzyme.
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$$20$$-$$25^o$$-C and $$7$$pH
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$$20$$-$$35^o$$-C and $$6.5$$ pH
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$$20$$-$$35^o$$-C and $$7.5$$pH
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All correct
Explanation
The optimum temp of enzymes is 20-35°C. They become inactivated at very low temperature and denatured (destroyed) at very high temp i.e. greater than 45°C. Low molecular weight enzymes are comparatively more heat stable. In archaebacterium Pyrococcus furiosus, the optimum temperature of hydrogenase is greater than 95°C. This heat-stable enzyme enables Pyrococcus to grow at 100°C. The optimum pH of most endoenzyme is pH 7.0 (neutral pH). However, digestive enzymes can function at different pH. For example, salivary amylase act best at pH 6.8, pepsin act best at pH2 etc. Any fluctuation in pH from the optimum causes ionization of R-groups of amino acids which decrease the enzyme activity. Sometimes a change in pH causes the reverse reaction, e.g. at pH 7.0 phosphorylase break down starch into glucose 1- phosphate while at pH5 the reverse reaction occurs.
So, the correct option is '20-25$$^o$$ C and 7.0 pH'
In plant glycolipids, the sugar is normally.
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oil
0%
wax
0%
glycolipid
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phospholipid
Explanation
Glycolipids yeild fatty acids, glycerol and carbohydrates on hydrolysis. Monogalactosyldiglycerides are glycolipids which are commonly found in plant leaves and algae. They contain a high proportion of poly unsaturated fatty acids and appear to play a role in photosynthesis.
The ultimate product of hydrolysis of starch is :
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glucose
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fructose
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sucrose
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None of these
Explanation
$$\text{starch is the polymer of glucose hence, on it's hydrolysis we get glucose as a product.}$$
Polynucleotides are ester of sugar with-
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Phosphorus acid
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Sulphuric acid
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Phosphoric acid
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Boric acis
Starch is:
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$$C_{12}H_{22}O_{11}$$
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$$C_6H_{10}O_5$$
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$$(C_6H_{10}O_5)_n$$
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$$(C_6H_{12}O_6)_n$$
Explanation
Starch is a polymeric carbohydrate consisting of large number of glucose units joined by glycosidic bonds.
Molecular formula of starch is $$\left( { C }_{ 6 }{ H }_{ 10 }{ O }_{ 5 } \right) n$$
Which among the following is the main constituent of Biogas?
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Methane
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Propane
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Butane
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Ethane
Some proteoltic enzymes are-
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Trypsin, Erepsin, pepsin
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Amylase, lipase, zymase
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Ampylopsin, stapsin, ptyalin
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Urease, Dehydrogenase, Zymase
Explanation
Proteolytic enzymes are those which help break down and digest proteins. They are essential for cell division, immune function, and protein recycling. Trypsin, Erepsin, and pepsin are the essential proteolytic enzymes. These enzymes help to break down protein in meat, eggs, and fish into simpler amino acids.
So, the correct answer is
Trypsin, Erepsin, pepsin
Item 'I'
(compound)
Item 'II'
(reagent)
(A) Lysine
(P)I-naphthol
(B)Furfural
(Q)ninhydrin
(C) Benzyl alcohol
(R) $$KMnO_4$$
(D)Styrene
(S)ceric ammonium
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(A) $$\to (Q)$$,(B) $$\to (P)$$, (C) $$\to (S)$$, (D) $$\to (R)$$
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(A) $$\to (Q)$$,(B) $$\to (R)$$, (C) $$\to (S)$$, (D) $$\to (P)$$
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(A) $$\to (Q)$$,(B) $$\to (P)$$, (C) $$\to (R)$$, (D) $$\to (S)$$
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(A) $$\to (R)$$,(B) $$\to (P)$$, (C) $$\to (Q)$$, (D) $$\to (S)$$
Explanation
Lysine - Ninhydrin
Furfural - I naphthol
Benzyl alcohol - ceric ammonium
Styrene - $$KMn{O}_{4}$$
Option A is correct
A compound with molecular mass 180 is acylated with $$CH_3COCl$$ to get a compound with molecular mass $$390$$. The number of amino groups present per molecule of former compound is:
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$$6$$
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$$2$$
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$$5$$
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$$4$$
Thiol group is present on:-
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Methionine
0%
Cytosine
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Cystine
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Cysteine
Enzyme which catalyse the joining of C - O, C - S, C - N, P - O bonds :
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Lyases
0%
transferases
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Hydrolases
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ligases
Cobalt as a rare element is essential in the synthesis of this vitamin _______.
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$$C$$
0%
$$D$$
0%
$$B_1$$
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$$B_{12}$$
Explanation
(D) Vitamin $$B_{12}$$
Because cobalt is also an essential trace element for humans and found at center of $$B_{12}$$ and produces red blood cells.
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