DPP - Daily Practice Problems

Chapter-wise Sheets
Date : Start Time : End Time :

CB09
SYLLABUS : Biomolecules

Max. Marks : 180 Marking Scheme : + 4 for correct & (–1) for incorrect Time : 60 min.

INSTRUCTIONS : This Daily Practice Problem Sheet contains 45 MCQs. For each question only one option is correct.
Darken the correct circle/ bubble in the Response Grid provided on each page.

1. A nucleotide is formed of 5. In RNA, thymine is replaced by

(a) Purine, pyrimidine and phosphate (a) Adenine (b) Guanine
(b) Purine, sugar and phosphate (c) Cytosine (d) Uracil
(c) Nitrogen base, sugar and phosphate 6. Which of the following is a reducing sugar?
(d) Pyrimidine, sugar and phosphate (a) Galactose (b) Gluconic acid
2. Glycogen is a polymer of (c) -methyl galactoside (d) Sucrose
(a) galactose (b) glucose 7. An enzyme that can stimulate germination of barley seeds
(c) fructose (d) sucrose is
3. Most abundant organic compound on earth is (a) lipase (b) protease
(a) Protein (b) Cellulose (c) invertase (d) -amylase
(c) Lipids (d) Steroids 8. Carrier ions like Na+ facilitate the absorption of substances
4. Protein synthesis in a cell takes place like:
(a) only in the cytoplasm (a) amino acids and glucose
(b) in the nucleolus as well as in cytoplasm (b) glucose and fatty acids
(c) in cytoplasm as well as in mitochondria (c) fatty acids and glycerol
(d) only on ribosomes attached to the nuclear envelope (d) fructose and some amino acids

RESPONSE 1. 2. 3. 4. 5.
GRID 6. 7. 8.
Space for Rough Work
 B-34 DPP/ CB09
9. An enzyme brings about 15. Sigmoid growth curve is represented by
(a) decrease in reaction time (a) dN/dt = rN
(b) increase in reaction time (b) dN/dt = rN (1 – N/K)
(c) increase in activation energy (c) Nt = No + B + I – D – E
(d) reduction in activation energy (d) dN/dt = 1 – N/K
10. The enzymes hexokinase which catalyses glucose to 16. A coenzyme is
glucose-6-phosphate in glycolysis is inhibited by glucose- (a) Same enzyme that occurs in different tissues such as
6-phosphate. This is an example of heart and muscle
(a) competitive inhibition (b) One that shares the function of other enzyme
(b) non-competitive inhibition (c) Organic or inorganic in nature and helps activate
metabolic enzymes
(c) feedback allosteric inhibition
(d) Organic non-protein in nature and helps to activate
(d) positive feedback
metabolic enzymes
11. The enormous diversity of protein molecules is due mainly
17. The most basic amino acid is
to the diversity of
(a) Arginine (b) Histidine
(a) amino groups on the amino acids
(c) Glycine (d) Glutamine
(b) R groups on the amino acids
18. Which of the following is not an aromatic amino acid?
(c) amino acid sequences within the protein molecule
(a) Valine (b) Tyrosine
(d) peptide bonds
(c) Phenylalanine (d) Tryptophan
12. Length of one turn of the helix in a B-form DNA is
approximately 19. The class of enzymes that catalyze the removal of a group
from a substrate without addition of water, leaving double
(a) 3.4 nm (b) 2 nm
bonds, is
(c) 0.34 nm (d) 20 nm
(a) Transferases (b) Dehydrogenases
13. The catalytic efficiency of two different enzymes can be
(c) Hydrolases (d) Lyases
compared by the
20. Which of the following is a component of vitamin (thiamine,
(a) formation of the product biotin), Acetyl CoA, cysteine, methionine and ferredoxin?
(b) pH optimum value (a) Fe (b) S
(c) Km value (c) Co (d) K
(d) molecular size of the enzyme 21. The helical structure of protein is stabilized by
14. Which of the following sets contains polysaccharides? (a) Ester (b) Peptide bonds
(a) Glucose, fructose, lactose (c) Disulphide bonds (d) Hydrogen bonds
(b) Starch, glycogen, cellulose 22. Cellulose is a polymer of
(c) Sucrose, maltose, cellulose (a) -glucose (b) -D-glucose
(d) Galactose, starch, sucrose (c) -D-glucose (d) -L-glucose

9. 10. 11. 12. 13.

RESPONSE
14. 15. 16. 17. 18.
GRID
19. 20. 21. 22.
Space for Rough Work
DPP/ CB09 B-35

23. The given graph shows the effect of substrate concentration Given structural formula is correctly identified alongwith its
on the rate of reaction of the enzyme green -gram - related function by which of the following options?
phosphatase. What does the graph indicate ? (a) Cholesterol – A component of animal cell membrane
(b) Lecithin – A component of cell membrane
(c) Triglyceride – An energy source
(d) Adenosine – A component of nucleic acids
27. Select the option that correctly identifies the chemical bonds
present in the given biomolecules.
Polysaccharides – A, Proteins – B, Fats – C, Water – D
A B C D
(a) Ester Peptide Glycosidic Hydrogen
(b) Glycosidic Peptide Ester Hydrogen
(a) The rate of enzyme reaction is directly proportional to (c) Glycosidic Peptide Hydrogen Ester
the substrate concentration (d) Hydrogen Ester Peptide Glycosidic
(b) Presence of an enzyme inhibitor in the reaction mixture 28. Which of the following statements is not correct regarding
(c) Formation of an enzyme-substrate complex chitin?
(d) At higher substrate-concentration the pH increases. (a) It is a storage polysaccharide
24. The Km value of the enzyme is the value of the substrate (b) It is a homopolysccharide
concentration at which the reaction reaches to (c) It is a constituent of arthropod exoskeleton and fungal
(a) Zero (b) 2 Vmax cell wall
(c) ½ Vmax (d) ¼ Vmax (d) It is the second most abundant carbohydrate on earth
25. Which group contains biocatalysts? 29. Which of the following secondary metabolites are used as
drugs?
(a) Myosin, oxytocin, adrenalin (a) Abrin and ricin
(b) Peptidase, amylase, rennin (b) Vinblastin and curcumin
(c) Glucose, amino acids, fatty acids (c) Anthocyanins
(d) Gums and cellulose
(d) Rhodopsin, pepsin, steapsin
30. Enzymes that catalyse removal of groups from substrates
26.
by mechanisms other than hydrolysis, and addition of
O
groups to double bonds, are called
O CH2 O C R1 (a) ligases (b) lyases
(c) hydrolases (d) dehydrogenases
R2 C O CH O 31. Which of the following statement is incorrect w.r.t. starch?
(a) Starch consists of unbranched amylose and branched
CH2 O P O CH2 CH2 amylopectin
(b) It is a polymer of -D-glucose
OH N+
(c) Successive glucose units are linked together by 1
CH3 CH 6 linkage and at branching 1 4 linkage is found
CH3 3
(d) Starch turns black with iodine

RESPONSE 23. 24. 25. 26. 27.

GRID 28. 29. 30. 31.

Space for Rough Work

 B-36 DPP/ CB09
32. Cellulose differs from chitin in 40. The structure of glucose and galactose are same except
(a) Branching with regard to
(b) Type of glycosidic bond (a) First carbon atom
(c) Type of monomer unit (b) Second carbon atom
(d) Abundancy in biosphere (c) Third carbon atom
33. Oils are rich in (d) Fourth carbon atom
41. All the following statements are true with regard to glucose,
(a) Glycerol that possesses three hydroxyl groups except :
(b) Saturated fatty acids (a) It is an aldohexose
(c) Fats that are generally liquid at room temperature (b) It is a reducing sugar
(d) Esters of fatty acids (c) It is present in starch and cellulose
34. Bonds that do not exist in tertiary structure of proteins (d) It is an epimer of fructose
(a) Covalent bonds 42. Guanylic acid is a
(b) Phosphodiester bonds (a) Nucleoside of purine
(c) Hydrophobic etnractions (b) Nucleoside of pyrimidine
(d) Ionic bonds (c) Nucleotide of purine
35. Cleavage of specific covalent bonds and removal of groups (d) Nucleotide of pyrimidine
without hydrolysis is the property of 43. Long chain molecules of fatty acids are formed by
(a) Isomerases (b) Lyases (a) Polymerisation of 2 carbon compounds
(c) Hydrolases (d) Transferases (b) Decomposition of fats
36. The catalytic efficiency of two different enzymes can be (c) Polymerisation of glycogen
compared by the (d) Conversion of glycogen
(a) Km value 44. Read the following four statements (A to D) and mark the
(b) pH value option that has both correct statements
(c) Formation of the product A. Blood conc. of glucose in a normal healthy man is 4.5
(d) Molecular size of the enzyme to 5.0 mM
37. Which of the following is an example of isozyme? B. In proteins only left handed helices are observed
(a) -Amylase C. The pitch of B- DNA is 3.4 Angstrom
(b) Glucokinase D. At each step of ascent the strand of DNA turns 36
(c) Lactate dehydrogenase degree
(d) All of these (a) A, B (b) B, C (c) C, D (d) A, D
38. Essential amino acids include 45. Which one of the following biomolecules is correctly
(a) leucine (b) valine characterized?
(c) tryptophan (d) all of these (a) Lecithin - A phosphorylated glyceride found in cell
39. Acidic amino acids have two –COOH groups and one – membrane.
NH2 group per molecule. Select the pair that consists of (b) Palmitic acid - An unsaturated fatty acid with 18 carbon
acidic amino acids. atoms.
(a) Aspartic acid, glutamic acid (c) Adenylic acid - Adenosine with a glucose phosphate
(b) Lysine, arginine molecule.
(c) Glycine, alanine (d) Alanine amino acid - Contains an amino group and an
(d) Both (a) and (b) acidic group anywhere in the molecule.

32. 33. 34. 35. 36.

RESPONSE
37. 38. 39. 40. 41.
GRID
42. 43. 44. 45.
Space for Rough Work

DAILY PRACTICE PROBLEM DPP CHAPTERWISE 9 - BIOLOGY

Total Questions 45 Total Marks 180
Attempted Correct
Incorrect Net Score
Cut-off Score 45 Qualifying Score 55
Success Gap = Net Score – Qualifying Score
Net Score = (Correct × 4) – (Incorrect × 1)
 HINTS & SOLUTIONS

DPP /CB09
12. (a) Length of one turn of DNA helix is 34Å.
1. (c) The nucleic acid (DNA and RNA) are repeating units of 1Å = 10–1 nm
nucleotides i.e. polynucleotides. Each nucleotide comprises 13. (c) Km (Michealis Menten constant) is defined as that substrate
of nitrogenous heterocyclic bases viz. purines or pyrimidines, concentration at which under optimum conditions the rate of
pentose sugar and phosphoric acid. an enzyme catalysed reaction reaches half the maximum rate.
2. (b) Glycogen is an animal starch, stored in the liver and is Km is inversely proportional to affinity of enzyme for its
polysaccharide of Glucose. About 30,000 glucose substrate.
molecules joined by 1-4 -glycosidic bonds and its 14. (b) 15. (a) 16. (d) 17. (a) 18. (a)
branches by 1-6 glycosidic bonds. It gives red colour with 19. (d) 20. (b) 21. (d) 22. (c) 23. (b)
iodine solution. 24. (c) 25. (b)
• Galactose is a monosaccharide from milk. 26. (b) Phospholipids are triglyceride lipids, in which one fatty acid
• Fructose is a monosaccharide from fruit. is replaced by phosphoric acid residue often linked to
• Sucrose is a disaccharide (Glucose + Fructose). additional nitrogenous groups like choline (in lecithin),
3. (b) Cellulose is the most abundant organic compound, most ethanolamine (in cephalin) etc.
abundant polysaccharide and most abundant biopolymer
CH2 O CO R1
found on earth.
4. (c) In the cytoplasm, protein synthesis is restricted to the CH CO R2
O
ribosomes. Mitochondria being a semiautonomous organelle,
has its own genetic machinery to synthesize its proteins. O
+
5. (d) RNA is a single chain of ribonucleotides. Each ribonucleotide CH2 O P (CH2)2 N(CH3)3
consists of nitrogenous bases (adenine, guanine, cytosine
O Choline
and uracil), ribose sugar and phosphoric acid.
Phosphate
6. (a) Reducing sugar is any sugar that has an aldehyde group or is Fig. : Structure of lecithin.
capable of forming one in solution through isomerisation.
Reducing monosaccharides include glucose, fructose, 27. (b) Polysaccharides, monosaccharides are linked together by
glyceraldehyde and galactose. Many disaccharides, like glycosidic bond (C–O–C). Water has hydrogen bonding.
lactose and maltose also have a reducing form, as one of the Proteins and polymers of different amino acids, which are
two units may have an open- chain form with an aldehyde linked by peptide (CONH) bond formed by dehydration
group. (polymerisation) between COOH group of one amino acid
However, sucrose and trihalose in which the anomeric carbons and NH2 group of next amino acid with the removal of H2O.
of the two units are linked together, are non reducing The three hydroxyl groups of a glycerol molecule join with
disaccharides since neither of the rings is capable of opening. the the carboxyl groups of three fatty acid molecules to form
7. (d) -amylase enzyme stimulates the germination of barley a fat or triglyceride molecule. The chemical linkage between
seed. the glycerol and fatty acids is called the ester bond.
8. (a) Massive ions like Na+ facilitate the absorption of substances 28. (a) Chitin is the second most abundant polysaccharide (after
like amino acid and glucose through cotransport. cellulose). Chitin is not a storage polysaccharide rather it is a
9. (d) Enzymes accelerate chemical reaction by lowering the structural homopolysaccharide, formed of N-
activation energy. acetylglucosamine (NAG) monomers joined together by -
10. (c) Competitive inhibition is the reversible inhibition of enzyme 1, 4 linkages. Also, it forms the structural component of
activity due to presence of substrate analogues. Non fungal walls and exoskeleton of arthropods.
competitive inhibition is the reduction of enzyme activity 29. (b)
by a factor that has no real structural similarity with the
substrate. Allosteric inhibition is reversible non- Some Secondary Metabolites
competitive inhibition occurring in case of allosteric Pigments Carotenoids, anthocyanins, etc.
enzymes . Herein, the inhibitors are the products or Alkaloids Morphine, Codeine, etc.
intermediates of reactions catalyzed by the enzymes.
Hence, it is also called end product inhibition or feedback Terpenoids Monoterpenes, Diterpenes, etc.
inhibition. Essential oils Lemon grass oil, etc.
11. (c) There are only 20 amino acids . These can be arranged in Toxins Abrin, Ricin
different order in the polypeptide chain to form a diverse Lectins Concanavalin A
array of proteins.
Drugs Vinblastin, Curcumin, etc.
Polymeric substances Rubber, Gums, Cellulose.
Vinblastin is used as an anticancer drug, whereas curcumin is a
component of turmeric and also used as drug.
30. (b) Lyases enzyme catalyze the breakage of specific covalent
bonds and removal of groups without hydrolysis producing
double bonds or removal of double bonds by adding groups
e.g., histidine decarboxylase that splits C–C bond of histidine,
forming CO2 and histamine.
X Y
| |
lyase
C— C X—Y C C
Fructose-1, 6 diphosphate Aldolase Dihydroxyacetone-3-
phosphate + Glyceraldehyde-3-phosphate.
31. (c) Successive glucose units are linked together by 1 4
linkage and at branchings 1 6 linkage is present.
32. (c) 33. (c)
34. (b) Tertiary structure of proteius is devoid of phosphodiester
bonds. There bonds are present in nudeic acids.
35. (b)
36. (a) A high k m indicates low affinity of an enzyme for its
substrate.
37. (d) The multiple molecular forms of an enzyme occuring in the
same organisms and having a similar substrate activity are
called isoenzymes or isozymes. They have similar properties
but different molecular weights and location. Over 100
enzymes are known to have isoenzymes. -amylase of wheat
endosperm has 16 isozymes, lactate dehydrogenase has 5
isozymes.
38. (d) Essential amino acids are the amino acids which cannot be
synthesized by organisms in the body and are obtained from
plants e.g., valine, leucine, isoleucine, phenylalanine, threonin,
lysine, tryptophan, methionine.
Non-essential amino acids can be synthesized by the organism
and may not be the requisite components of diet e.g., serine,
tryosine, aspartate, cysteine, glutamate, proline, glycrine,
alanine, asparagine, glutamine and tyrosine.
39. (a) Acidic amino acids have an extra carboxylic group (mono-
amino dicarboxylic), e.g., glutamate (glutamic acid, Glu),
asparate (aspartic acid, Asp).
Basic amino acids have an additional amino group without
forming amides (diamino monocarboxylic), e.g., arginine
(Arg), lysine (Lys).
Neutral amino acids have one amino group and one carboxylic
group (mono-amino mnocarboxylic) with noncyclic
hydrocarbon chain, e.g., glycine (Gly), alanine (Ala), valine
(Val), Leucine (Leu), isoleucine (lle). Essential amino acids
are the amino acids which cannot be synthesized by organisms
in the body and are obtained from plants e.g., valine, leucine,
isoleucine, phenylalanine, threonin, lysine, tryptophan,
methionine.
Non-essential amino acids can be synthesized by the organism
and may not be the requisite components of diet e.g., serine,
tryosine, aspartate, cysteine, glutamate, proline, glycrine,
alanine, asparagine, glutamine and tyrosine.
40. (d)
41. (b) Trehalose is a non-reducing sugar. It is made up to 2 molecules
of glucose
42. (c) 43. (a) 44. (d)
45. (a) Palmitic acid is one of the most common saturated fatty
acids found in animals and plants. It has 16 carbons including
the carboxyl carbon.