Sure Shot Questions
Chapter – 10
Biomolecules
MCQ
(1 mark)
1. Glycogen is a branched chain polymer of   D 
glucose units in which chain is formed by C1 – C4
glycosidic linkage whereas branching occurs by the
formation of C1 – C6 glycosidic linkage. Structure
of glycogen is similar to ________.
(a) amylose
(b) amylopectin
(c) cellulose
(d) glucose
2. Sucrose (cane sugar) is a disaccharide. One
molecule of sucrose on hydrolysis gives _____.
(a) 2 molecules of glucose
(b) 2 molecules of glucose + 1 molecule of
fructose
(c) 1 molecule of glucose +1 molecule of fructose
(d) 2 molecules of fructose
3. Proteins are found to have two different types of
secondary structures viz.  -helix and  -pleated
sheet structure.  -helix structure of protein is
stabilized by
(a) Peptide bonds
(b) Van der Waal’s forces
(c) Hydrogen bonds
(d) Dipole – dipole interactions.
4. In disaccharides, if the reducing groups of
monosaccharides i.e., aldehydic or ketonic groups
are bonded, these are non – reducing sugars.
Which of the following disaccharide is a nonreducing sugar?
5. Which of the following acids is a vitamin?
(a) Aspartic acid
(b) Ascorbic acid
(c) Adipic acid
(d) Saccharic acid
6. Dinucleotide is obtained by joining two nucleotides
together by phosphodiester linkage. Between
which carbon atoms of pentose sugars of
nucleotides are these linkage present?
(a) 5’ and 3’
(b) 1’ and 5’
(c) 5’ and 5’
(d) 3’ and 5’
7. Nucleic acids are the polymers of _______.
(a) nucleosides
(b) nucleotides
(c) bases
(d) sugars
8. Which of the following statements is not true
about glucose?
(a) It is an aldohexose.
(b) On heating with HI it forms «-hexane.
(c) It is present in furanose form,
(d) It does not give 2, 4-DNP test.
9. Each polypeptide in a protein has amino acids
linked with each other in a specific sequence. This
sequence of amino acids is said to be .
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10.
11.
12.
13.
(a) primary structure of proteins
(b) secondary structure of proteins
(c) tertiary structure of proteins
(d) quaternary structure of proteins
DNA and RNA contain four bases each. Which of
the following bases is not present in RNA?
(a) Adenine
(b) Uracil
(c) Thymine
(d) Cytosine
Which of the following B – group vitamins can be
stored in our body?
(a) Vitamin B1
(b) Vitamin B2
(c) Vitamin B6
(d) Vitamin B12
Which of the following bass is not present in DNA?
(a) Adenine
(b) Thymine
(c) Cytosine
(d) Uracil
Three cyclic structures of monosaccharides are
given below. Which of these are anomers?
(a) I, II, III
(b) II, III
(c) I, II
(d) III
16. Which of the following is a polysaccharide?
(a) Glucose
(b) Maltose
(c) Glycogen
(d) Lactose
[Term I, 2021 – 22]
17. Which one of the following statements is correct
about sucrose?
(a) It can reduce Tollen's reagent, however
cannot reduce Fehling's reagent.
(b) It undergoes mutarotation like glucose and
fructose.
(c) It undergoes inversion in the configuration on
hydrolysis.
(d) It is laevorotatory in nature.
[Term I, 2021 – 22]
18. In the following reaction, identify A and B.
(a) I and II
(b) II and III
(c) I and III
(d) III is anomer of I and II
14. Which of the following reactions of glucose can be
explained only by its cyclic structure?
(a) Glucose forms pentaacetate.
(b) Glucose reacts with hydroxylamine to form an
oxime,
(c) Pentaacetate of glucose does not react with
hydroxylamine.
(d) Glucose is oxidised by nitric acid to gluconic
acid.
15. Optical rotations of some compounds along with
their structures are given below. Which of them
have D-configuration?
19. Dissacharides that are reducing in nature are
(a) sucrose and lactose
(b) sucrose and maltose
(c) lactose and maltose
(d) sucrose, lactose and maltose.
[2020 – 21]
20. Which of the following statements is correct?
(a) Fibrous proteins are generally soluble in
water.
(b) Albumin is an example of fibrous protein.
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(c) In fibrous proteins, the structure is stabilised
(a) Both Assertion (A) and Reason (R) are true and
by hydrogen bonds and disulphide bonds.
Reason (R) is the correct explanation of the
(d) pH does not affect the primary structure of
Assertion (A)
protein.
[Term I, 2021 – 22]
 Assertion-Reasoning
(1 mark)
(b) Both Assertion (A) and Reason (R) are true, but
Reason (R) is not the correct explanation of the
Assertion (A)
21. Assertion (A): Sucrose is a non-reducing sugar.
Reason (R): Sucrose has glycosidic linkage.
(a) Both Assertion (A) and Reason (R) are correct
statements, and Reason (R) is the correct
explanation of the Assertion (A).
statements, but Reason (R) is not the correct
explanation of the Assertion (A).
(c) Assertion (A) is correct, but Reason (R) is
incorrect statement.
[2020]
22. Assertion (A): Albumin is a globular protein.
Reason (R): Polypeptide chain coils around to give
a straight chain.
(a) Both assertion (A) and reason (R) are correct
statements, and reason (R) is the correct
explanation of the assertion (A).
24. Given below are two statements labelled as
Assertion (A) and Reason (R).
different types of secondary structures viz alpha
helix and beta-pleated sheet structure.
Reason (R): The secondary structure of proteins is
stabilized by hydrogen bonding.
options given below:
(a) Both A and R are true and R is the correct
explanation of A.
(b) Both A and R are true but R is not the correct
explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
25. Assertion : The two strands are complementary to
(b) Both assertion (A) and reason (R) are correct
statements, but reason (R) is not the correct
explanation of the assertion (A).
(c) Assertion (A) is correct, but reason (R) is
incorrect statement.
(d) Assertion (A) is incorrect, but reason (R) is
[2020]
23. Assertion : The backbone of DNA and RNA
molecules is a chain consisting of heterocyclic
base, pentose sugar and phosphate group.
Reason : Nucleotides and nucleosides mainly differ
from each other in presence of phosphate group,
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[2023]
Select the most appropriate answer from the
(d) Assertion (A) is incorrect, but Reason (R) is
correct statement.
(d) Assertion (A) is false, but Reason (R) is true.
Assertion (A) : Proteins are found to have two
(b) Both Assertion (A) and Reason (R) are correct
correct statement.
(c) Assertion (A) is true, but Reason (R) is false.
each other.
Reason : The hydrogen bonds are formed
between specific pairs of bases.
(a) Assertion and reason both are correct
statements and reason is correct explanation for
assertion.
(b) Assertion and reason both are correct
statements but reason is not correct explanation
for assertion.
(c) Assertion is correct statement but reason is
wrong statement.
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(d) Assertion is wrong statement but reason is
(i) What are amino acids?
correct statement.
(ii) Why are amino acids amphoteric?
[2020 – 21]
26. Assertion (A): DNA undergoes replication.
Reason (R): DNA contains cytosine and thymine as
pyrimidine bases.
(iii) Give one point of difference between acidic
and basic amino acid.
(iv) What are essential amino acids?
a) Both A and R are true and R is the correct
explanation of A.
b) Both A and R are true but R is not the correct
explanation of A.
c) A is true but R is false.
d) A is false but R is true.
(v) Name the linkage formed when carboxyl end
of one amino acid condenses with amino end of
other amino acid.
[2020]
29. Strengthening the Foundation: Chargaff
Formulates His “Rules”
Many people believe that James Watson and
27. Assertion: Fructose has a total of 16 optical
isomers.
Reason: There are total of 3 asymmetric centers.
a) If both Assertion and Reason are right and
Reason is the right explanation of Assertion.
b) If both Assertion and Reason are right but
Reason is not the right explanation of Assertion.
c) If Assertion is right but Reason is wrong.
d) If both Assertion and Reason are wrong.
Case Study
[5 Marks]
Francis Crick discovered DNA in the 1950s. In
reality, this is not the case. Rather, DNA was first
identified in the late 1860s by Swiss chemist
Friedrich Miescher.
Then, in the decades following Miescher's
discovery, other scientists-notably, Phoebus
Levene and Erwin Chargaff carried out a series of
research efforts that revealed additional details
about the DNA molecule, including its primary
28. Read the given passage and answer the questions
number (i) to (v) that follows:
1x5 = 5
chemical components and the ways in which they
joined with one another. Without the scientific
Organic compounds containing amine as functional
foundation provided by these pioneers, Watson
group are present in a vivid variety of compounds,
and Crick may never have reached their
namely amino acids, hormones, neurotransmitters,
groundbreaking conclusion of 1953: that the DNA
DNA, alkaloids, dyes, etc. Drugs including nicotine,
molecule exists in the form of a three-
morphine, codeine and heroin, etc. which have
dimensional double helix. Chargaff, an Austrian
physiological effects on humans also contain
biochemist, as his first step in this DNA research,
amino group in one form or another. Amines are
set out to see whether there were any
basic because of the presence of lone pair of
differences in DNA among different species.
electrons on nitrogen.
After developing a new paper chromatography
Addition of nitrogen into an organic framework
method for separating and identifying small
leads to the formation of two families of
amounts of organic material, Chargaff reached
molecules, namely amines and amides. As
two major conclusions:
chemistry students, we must appreciate the
(i) the nucleotide composition of DNA varies
versatility of nitrogen.
among species.
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(ii) Almost all DNA, no matter what organism or
nucleotides present in this segment of DNA?
tissue type it comes from maintains certain
(b) A sample of hair and blood was found at two
properties, even as its composition varies. In
sites. Scientists claim that the samples belong
particular, the amount of adenine (A) is similar
to same species. How did the scientists arrive at
to the amount of thymine (T), and the amount
this conclusion?
of guanine (G) approximates the amount of
(c) The sample of a virus was tested and it was
cytosine (C). In other words, the total amount
found to contain 20% adenine, 20% thymine, 20
of purines (A + G) and the total amount of
% guanine and the rest cytosine. Is the genetic
pyrimidines (C + T) are usually nearly equal. This
material of this virus (a) DNA- double helix (b)
conclusion is now known as "Chargaffs rule."
DNA-single helix (c) RNA? What do you infer
Chargaff's rule is not obeyed in some viruses.
from this data?
These either have single- stranded DNA or RNA
OR
as their genetic material.
How can Chargaff’s rule be used to infer that the
Answer the following questions:
genetic material of an organism is double – helix
(a) A segment of DNA has 100 adenine and 150
or single – helix?
[2022 – 23]
cytosine bases. What is the total number of
Questions
30. Define the following terms with a suitable example of each:
(a) Anomers (b) Essential amino acids
(c) Denaturation of protein
31. What is the difference between fibrous protein and globular protein?
32. What is the difference between acidic amino acids and basic amino acids?
Ans. Acidic amino acids are those which contain more number of carboxyl groups as compared to amino groups
whereas basic amino acids are those which contains more number of amino groups than carboxyl groups.
33. Write the name of the vitamin whose deficiency causes bleeding of gums.
34. Deficiency of which vitamin causes night – blindness?
35. Deficiency of which vitamin causes rickets?
36. Deficiency of which vitamin causes scurvy?
37. Enumerate the reactions of glucose which cannot be explained by its open chain structures.
38. Define denaturation of protein. What is the effect of denaturation on the structure of protein?
39. Define the following terms:
(i) Glycosidic linkage (ii) Invert sugar
(iii) Oligosaccharides
[Al 2014]
40. Differentiate between the following:
(i)
Amylose and Amylopectin
(ii)
Peptide linkage and Glycosidic linkage
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(iii)
Fibrous proteins and Globular proteins.
[Delhi 2019]
41.Enumerate the reactions of glucose which cannot be explained by its open chain
structures.
42.Write down the structures and names of the products formed when D-glucose is treated
with
(i) Hydroxylamine
(ii) Acetic anhydride.
43.Write down the structures and names of the products formed when D-glucose is treated
with
(i) Bromine water
(ii) Hydrogen iodide (Prolonged heating).
44.What is essentially the difference between a-glucose and 13-glucose? What is meant by
pyranose structure of glucose?
45.Differentiate between the following :
(i) Amylose and Amylopectin
(ii) Peptide linkage and Glycosidic linkage
(iii) Fibrous proteins and Globular proteins.
46. Where does the water present in the egg go after boiling the egg?
47.Write the main structural difference between DNA and RNA. Of the four bases, name
those which are common to both DNA and RNA.
48.What is difference between a nucleoside and nucleotide?
49.Define the following with an example of each
(i) Denatured protein
(ii) Essential amino acids
50.Define the following terms:
(i)Glycosidic linkage
(ii) Invert sugar
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51.A non-reducing disaccharide ‘A’ on hydrolysis with dilute acid gives an equimolar
mixture of D-(+)-glucose and D-(-)-Fructose.
𝐷𝑖𝑙.𝐻𝐶𝐼
𝐴 + 𝐻2 𝑂 →
𝐶6 𝐻12 𝑂6 + 𝐶6 𝐻12 𝑂6
0
[𝛼]𝐷 = +66. 5
+ 52. 5𝑜
− 92. 4𝑜
Identify A. What is the mixture of D-(+)- glucose and D-(-)- Fructose known as? Name
the linkage that holds the two units in the disaccharide.
52. How do you explain the amphoteric nature of amino acids?
53.What is the effect of denaturation on the structure of proteins?
54.How do you explain the presence of an aldehydic group in a glucose molecule?
55.Give any one property of glucose that cannot be explained by the open chain structure.
56.What is the difference between a nucleoside and a nucleotide?
57.What type of bonding helps in stabilizing the 𝛼 −helix structure of proteins?
58.Write one difference between 𝛼 − Helix and 𝛽 −pleated structures of proteins.
59.The melting points and solubility in water of amino acids are generally higher than that
of the corresponding halo acids. Explain.
60. Write chemical reactions to show that open structure of D-glucose contains the
following:
(i) Straight chain
(ii) Five alcohol groups
(iii) Aldehyde as carbonyl group.
61. What happens when D-glucose is treated with the following reagents?
(a) 𝐵𝑟2 water (b) 𝐻𝐶𝑁
(c) (𝐶𝐻3 𝐶𝑂)2 𝑂
62. Differentiate between the following:
(i) Amylose and Amylopectin
(ii) Peptide linkage and Glycosidic linkage
(iii) Fibrous proteins and Globular proteins.
63. Give the plausible explanation for the following:
(a) Glucose doesn't give 2,4 − 𝐷𝑁𝑃 test.
(b) The two strands in DNA are not identical but are complementary.
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