1. In double helix of DNA, the two DNA strands are
(a) coiled around a common axis
(b) coiled around each other
(c) coiled differently
(d) coiled over protein sheath
2. RNA does not possess
(a) Uracil
(b) Thymine
(c) Adenine
(d) Cytosine
3. Which is not consistent with double helical structure of
(b) Density of DNA decreases on heating
(c) A + T/C + G is not constant
(d) Both A and B
4. A nucleotide is formed of
(a) Purine, pyrimidine and phosphate
(b) Purine, sugar and phosphate
(c) Nitrogen base, sugar and phosphate
(d) Pyrimidine, sugar and phosphate
5. Mineral associated with cytochrome is
(a) Cu
(b) Mg
(c) Fe and Mg
(d) Fe and Cu
6. In RNA, thymine is replaced by
(a) Adenine
(b) Guanine
(c) Cytosine
(d) Uracil
7. The basic unit of nucleic acid is
(a) Pentose sugar
(b) Nucleoid
(c) Nucleoside
(d) Nucleotide
8. A segment of DNA has 120 adenine and 120 cytosine bases. The total number of nucleotides present in the segment is
(a) 120
(b) 240
(c) 60
(d) 480
9. DNA is composed of repeating units of (a) Ribonucleosides DNA?
(a) A = T, C = G
(b) Deoxyribonucleosides
(c) Ribonucleotides
(d) Deoxyribonucleotides
10. Enzymes having slightly different molecular structure but performing identical activity are
(a) Holoenzymes
(b) Isoenzymes
(c) Apoenzymes
(d) Coenzymes
11. Adenine is
(a) Purine
(b) Pyrimidine
(c) Nucleoside
(d) Nucleotide
12. Living cell contains 60 – 75% water. Water present in human body is
(a) 60 – 65%
(b) 50 – 55%
(c) 75 – 80%
(d) 65 – 70%
13. Amino acids are produced from
(a) Proteins
(b) Fatty acids
(c) Essential oils
(d) a-keto acids
14. Which is distributed more widely in a cell?
(a) DNA
(b) RNA
(c) Chloroplasts
(d) Sphaerosomes
15. Which is wrong about nucleic acids?
(a) DNA is single stranded in some viruses
(b) RNA is double stranded occasionally
(c) Length of one helix is 45Å in B-DNA
(d) One turn of Z-DNA has 12 bases
16. An enzyme brings about
(a) decrease in reaction time
(b) increase in reaction time
(c) increase in activation energy
(d) reduction in activation energy
17. The four elements making 99% of living system are
(a) CHOS
(b) CHOP
(c) CHON
(d) CNOP
18. Which one contains four pyrimidine bases?
(a) GATCAATGC
(b) GCUAGACAA
(b) UAGCGGUAA
(d) TGCCTAACG
19. Two free ribonucleotide units are interlinked with
(a) peptide bond
(b) covalent bond
(c) hydrogen bond
(d) phosphodiester bond
20. A polysaccharide, which is synthesized and stored in liver cells, is
(a) lactose
(b) galactose
(c) arabinose
(d) glycogen
21. The pyrenoids are made up of
(a) proteinaceous centre and starchy sheath
(b) core of protein surrounded by fatty sheath
(c) core of starch surrounded by sheath of protein
(d) core of nucleic acid surrounded by protein sheath
22. The nitrogenous organic base purine occuring in RNA is
(a) cytosine
(b) thymine
(c) guanine
(d) uracil
23. In which one of the following groups, all the three are examples of polysaccharides?
(a) Starch, glycogen, cellulose
(b) Sucrose, maltose, glucose
(c) glucose, fructose, lactose
(d) Galactose, starch, sucrose
24. Most diverse macromolecules, found in the cell both physically and chemically are
(a) proteins
(b) carbohydrates
(c) nucleic acids
(d) lipids.
25. Genes are packed into a bacterial chromosome by
(a) histones
(b) basic proteins
(c) acidic proteins
(d) actin
26. Protein synthesis in an animal cell takes place
(a) only in the cytoplasm
(b) in the nucleolus as well as in cytoplasm
(c) in cytoplasm as well as in mitochondria
(d) only on ribosomes attached to the
nuclear envelope
27. DNA synthesis can be specifically measured by estimating the incorporation of radio labelled
(a) uracil
(b) adenine
(c) thymidine
(d) deoxyribose sugar
28. The RNA that picks up specific amino acids from the amino acid pool in the cytoplasm to ribosome during protein synthesis is called
(a) mRNA
(b) tRNA
(c) rRNA
(d) carrier RNA
29. Radioactive thymidine when added to the medium surrounding living mammalian cells gets incorporated into the newly synthesized DNA. Which of the following types of chromatin is expected to become radioactive if cells are exposed to radioactive thymidine as soon as they enter the S-phase?
(a) Heterochromatin
(b) Euchromatin
(c) Both heterochromatin and euchromatin
(d) Neiher heterochromatin nor euchromatin but only the nucleous
30. The enormous diversity of protein molecules is due mainly to the diversity of
(a) amino groups on the amino acids
(b) R groups on the amino acids
(c) amino acid sequences within the protein molecule
(d) peptide bonds
31. Cellulose, the most important constitutent of plant cell wall is made of
(a) unbranched chain of glucose molecules linked by a-1, 4 glycosidic bond
(b) branched chain of glucose molecules linked by b-1, 4 glycosidic bond in straight chain and a-1, 6 glycosidic bond at the site of branching
(c) unbranched chain of glucose molecules linked by b-1, 4 glycosidic bond
(d) branched chain of glucose molecules linked by a-1, 6 glycosidic bond at the site of branching.
32. Lactose is composed of
(a) Glucose + Glucose
(b) Glucose + Fructose
(c) Fructose + Galactose
(d) Glucose + Galactose.
33. Minor changes at gene level are described as
(a) Point mutations
(b) Chromosomal mutations
(c) Reverse mutations
(d) Forward mutations
34. The secondary structure of that portion of an integral protein that is buried in the lipid bilayer of a cell membrane is
(a) b-strand
(b) b-bend
(c) random coil
(d) a-helix
35. Length of one turn of the helix in a b-form DNA is approximately
(a) 3.4 nm
(b) 2 nm
(c) 0.34 nm
(d) 20 nm
36. Conjugated proteins containing carbohydrates as prosthetic group are known as
(a) Chromoproteins
(b) Glycoproteins
(c) Lipoproteins
(d) Nucleoproteins
37. The transfer RNA molecule in 3D appears
(a) L-shaped
(b) E-shaped
(c) Y-shaped
(d) S-shaped
38. One of the similarities between DNA and RNA is that both
(a) are polymers of nucleotides
(b) are capable of replicating
(c) have similar sugars
(d) have similar pyrimidine bases
39. Feedback inhibition of an enzymatic reaction is caused by
(a) End product
(b) Substrate
(c) Enzyme
(d) Rise in temperature
40. Enzymes enhance the rate of reaction by
(a) forming a reactant-product complex
(b) changing the equilibrium point of the reaction
(c) combining with the product as soon as it is formed
(d) lowering the activation energy of the reaction
41. Which is an essential amino acid?
(a) Serine
(b) Aspartic acid
(c) Glycine
(d) Phenylalanine
42. Due to discovery of which of the following in 1980 the evolution was termed as RNA world?
(a) mRNA, tRNA, rRNA synthesise proteins
(b) In some virus RNA is genetic material
(c) RNA have enzymatic property
(d) RNA is not found in all cells
43. Most abundant organic compound on earth is
(a) Protein
(b) Cellulose
(c) Lipids
(d) Steroids
44. Types of RNA polymerase required in nucleus for RNA synthesis?
(a) 1
(b) 2
(c) 3
(d) 4
45. Spoilage of oil can be detected by which fatty acid?
(a) Oleic acid
(b) Linolenic acid
(c) Linoleic acid
(d) Erucic acid
46. Lipids are insoluble in water because lipid molecules are
(a) hydrophilic
(b) hydrophobic
(c) neutral
(d) zwitter ions
47. Which of the following is a reducing sugar?
(a) galactose
(b) gluconic acid
(c) beta -methyl galactoside
(d) sucrose
48. Collagen is
(a) fibrous protein
(b) globular protein
(c) lipid
(d) carbohydrate
49. Cancer cells are more easily damaged by radiation than normal cells because they are
(a) starved of mutation
(b) undergoing rapid division
(c) different in structure
(d) non-dividing
50. In which one of the following enzymes, is copper necessarily associated as an activator?
(a) Carbonic anhydrase
(b) Tryptophanase
(c) Lactic dehydrogenase
(d) Tyrosinase
51. Which form of RNA has a structure
resembling clover leaf?
(a) rRNA
(b) hn RNA
(c) m RNA
(d) t RNA
52. Which of the following statements regarding enzyme inhibition is correct?
(a) Competitive inhibition is seen when a substrate competes with an enzyme for binding to an inhibitor protein.
(b) Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme.
(c) Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate.
(d) Non-competitive inhibitors often bind to the enzyme irreversibly.
53. The catalytic efficiency of two different enzymes can be compared by the
(a) formation of the product
(b) pH optimum value
(c) Km value
(d) molecular size of the enzyme
54. Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these
(a) help in regulating metabolism
(b) are exclusively synthesized in the body of a living organism as at present
(c) are conjugated proteins
(d) enhance oxidative metabolism
55. Which of the following is the simplest amino acid?
(a) Alanine
(b) Asparagine
(c) Glycine
(c) Tyrosine
56. Which one of the following hydrolyses internal phosphodiester bonds in a polynucleotide chain?
(a) Lipase
(b) Protease
(c) Endonuclease
(d) Exonuclease
57. Antiparallel strands of a DNA molecule means that
(a) the phosphate groups of two DNA strands, at their ends. share the same position
(b) the phosphate groups at the start of two DNA strands are in opposite position (pole)
(c) one strand turns clockwise
(d) one strand turns anti-clockwise
58. Carbohydrates, the most abundant biomolecules on earth, are produced by:
(a) some bacteria, algae and green plant cells
(b) fungi, algae and green plant cells
(c) all bacteria, fungi and algae
(d) viruses, fungi and bacteria
59. An organic substance bound to an enzyme and essential for its activity is called
(a) Holoenzyme
(b) Apoenzyme
(c) Isoenzyme
(d) Coenzyme
60. About 98 percent of the mass of every living organism is composed of just six element including carbon, hydrogen, nitrogen, oxygen and
(a) sulphur and magnesium
(b) magnesium and sodium
(c) calcium and phosphorus
(d) phosphorus and sulphur.
61. A competitive inhibitor of succinic dehydrogenase is
(a) Malonate
(b) Oxaloacetate
(c) m-ketoglutarate
(d) Malate
62. Carrier ions like Na+ facilitate the absorption of substances like:
(a) amino acids and glucose
(b) glucose and fatty acids
(c) fatty acids and glycerol
(d) fructose and some amino acids
63.Conezyme is ……….
(a) oftern a vitamin
(b) Always an inorganic compound
(c) Always a protein
(d) Often metal
64.Who got Nobel Prize in 1978 for working enymes ?
(a) Koshland
(b) Arber and Nathans
(c) Nass and Nase
(d) H.G. Khorana
65. Chitin occurs in ……
(a) Crab
(b) Caterpillar
(c) Agaricus
(d) both a & c 66.
66.Which one is the most abundant protein in the animal world
(a) Trypsin
(b) Haemoglobin
(c) Collagen
(d) Insulin
67. The essential chemical components of many coenzymes are:
(a) Nucleic acids
(b) Carbohydrates
(c) Vitamins
(d) Proteins
68. Which one of the following biomolecules is correctly characterized?
(a) Lecithin – A phosphorylated glyceride found in cell membrane.
(b) Palmitic acid – An unsaturated fatty acid with 18 carbon atoms.
(c) Adenylic acid – Adenosine with a glucose phosphate molecule.
(d) Alanine amino acid – Contains an amino group and an acidic group anywhere in the
molecule.
69. A phosphoglycerate is always made up of:
(a) only an unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
(b) a saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
(c) a saturated or unsaturated fatty acid esterified to a phosphate group which is also attached to a glycerol molecule.
(d) only a saturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached
70. The essential chemical components of many coenzymes are:
(a) Nucleic acids
(b) Carbohydrates
(c) Vitamins
(d) Proteins
71. Transition state structure of the substrate formed during an enzymatic reaction is:
(a) permanent but unstable
(b) transient and unstable
(c) permanent and stable
(d) transient but stable
72. Macro molecule chitin is:
(a) Phosphorus containing polysaccharide
(b) Sulphur containing polysaccharide
(c) Simple polysaccharide
(d) Nitrogen containing polysaccharide
73. Which of the following statements
about enzymes is wrong?
(a) Enzymes require optimum pH and temperature for maximum activity
(b) Enzymes are denatured at high temperatures
(c) Enzymes are mostly proteins but some are lipids also
(d) Enzymes are highly specific
74. Which one is fibrous protein …..?
(a) Collagen
(b) Globulin
(c) Haemoglobin
(d) Hordein
75.Find out the correct combination ….
(i) Triose sugar – Ribose.
(ii) Starch – amylase and amylopectin
(iii) Plasma membarane – phospholipid
(iv) Malanin – sterols
(v) Pitutary hormones – peptide.
(a) Only ii, iii and iv
(b) Only I, ii and iii
(c) Only I and iii
(d) Only ii, iii and v
76.Which of the following are not polymeric?
(a) Proteins
(b) Lipids
(c) Polysaccharides
(d) Nucleic acids
77.Which of the following is the least likely to be involved in stabilizing the three dimensional folding of most proteins?
(a) Hydrogen bonds
(b) Electrostatic interaction
(c) Hydrophobic interaction
(d) Ester bonds
78.Which one of the following statements is wrong?
(a) Uracil is a pyrimidine.
(b) Glycine is a sulphur containing amino acid.
(c) Sucrose is a disaccharide.
(d) Cellulose is a polysaccharide
79.Carbohydrates are commonly found as starch in plants storage organs. Which of the following five properties of starch (15) make it useful as a storage material?
(1) Easily translocated
(2) Chemically nonreactive
(3) Easily digested by animals
(4) Osmotically inactive
(5) Synthesized during photosynthesis
The useful properties are
(a)(1), (3) and (5)
(b) (2) and (4)
(c) (1) and (5)
(d) (2) and (3)
80.Most common monomer of Carbohydrate is…
(a) Glucose
(b) Fructose
(c) Sucrose
(d) Maltose
81.Cofactor (prosthetic group) is a part of holoenzyme. It is
(a) loosely attached organic part
(b) loosely attached inorganic part
(c) accessory nonprotein substance attached firmly
(d) none of these
82.A typical fat molecule is made up of
(a) one glycerol and one fatty acid molecule
(b) three glycerol and three fatty acid molecules
(c) three glycerol molecules and one fatty acid molecule
(d) one glycerol and three fatty acid molecules.
83.The chitinous exoskeleton of arthropods is formed by the polymerisation of
(a) N acetyl glucosamine
(b) lipoglycans
(c) keratin sulphate and chondroitin sulphate
(d) D glucosamine
84.Generally protein and carbohydarte components are found in cow milk…
(a) Albumin, Lactose
(b) Globulin, Casin
(c) Casein, Lactose
(d) Casein, Fructose
85.Select the option which is not correct with respect to enzyme action.
(a) Substrate binds with enzyme at its active site.
(b) Addition of lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate.
(c) A noncompetitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.
(d) Malonate is a competitive inhibitor of succinic dehydrogenase.
86.Which of the following set of three items are not true as each set belongs to the category mentioned against them
(a) Lysine, glycine, thiamine – Amino acids
(b) Myosin, oxytocin and gastrin – Hormones
(c) Rennin, helicase and hyaluronidase – Enzyme
(d) Optic nerve, occulomotor, vagus – Sensory nerves
87.Which of the following nucleotide sequences contains 4 pyrimidine bases?
(a) GATCAATGC
(b) GCUAGACAA
(c) UAGCGGUAA
(d) Both (b) and (c)
88.Inorganic catalyst work efficiently at ________temperature and ________ pressure.
(a) low, high
(b) high, high
(c) low, low
(d) high, low
89.Uridine, present only in RNA is a
(a) nucleoside
(b) purine
(c) nucleotide
(d) pyrimidine
90.Which one of the following is wrong statement?
(a) Anabaena and Nostoc are capable of fixing nitrogen in freeliving state also
(b) Root nodule forming nitrogen fixers live as aerobes under freeliving conditions
(c) Phosphorus is a constituent of cell membranes, certain nucleic acids and all proteins
(d) Nitrosomonas and Nitrobacter are chemoautotrophs
91.The catalytic efficiency of two different enzymes can be compared by the
(a) formation of the product
(b) pH of optimum value
(c) K m value
(d) molecular size of the enzyme
92.The major role of minor elements inside living organisms is to act as
(a) constituent of hormones
(b) cofactors of enzymes
(c) building blocks of important amino acids
(d) binder of cell structure.
93.Which of the following is a reducing sugar?
(a) Galactose
(b) Gluconic acid
(c) bmethyl galactoside
(d) Sucrose
94.Which is not consistent with double helical structure of DNA?
(a) Density of DNA decreases on heating.
(b) A + T/C + G is not constant.
(c) A = T, C = G
(d) Both (a) and (b)
95.Which one of the following statements is correct, with reference to enzymes ?
(a) Holoenzyme = Apoenzyme + Coenzyme
(b) Coenzyme = Apoenzyme + Holoenzyme
(c) Holoenzyme = Coenzyme + Co-factor
(d) Apoenzyme = Holoenzyme + Coenzyme
96.Which of the following are not polymeric ?
(a) Proteins
(b) Polysaccharides
(c) Lipids
(d) Nucleic acids
97.The two functional groups characteristic of sugars are
(a) Hydroxyl and methyl
(b) Carbonyl and methyl
(c) Carbonyl and hydroxyl
(d) Carbonyl and phosphate
98.Concanavalin A is
(a) an alkaloid
(b) an essential oil
(c) a lectin
(d) a pigment
99.Consider the following statement :
(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.
(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme. Select the correct option.
(1) Both (A) and (B) are true.
(2) (A) is true but (B) is false.
(3) Both (A) and (B) are false.
(4) (A) is false but (B) is true.
100.Which of the following glucose transporters is insulin-dependent?
(a) GLUT I
(b) GLUT II
(c) GLUT III
(d) GLUT IV
101.Identify the basic amino acid from the following.
(a) Lysine
(b) Valine
(c) Tyrosine
(d) Glutamic Acid
102.Which one of the following is the most abundant protein in the animals?
(a) Lectin
(b) Insulin
(c) Haemoglobin
(d) Collagen
103.Match the following
(a) Inhibitor of catalytic activity
(i) Ricin
(b) Possess peptide bonds
(ii) Malonate
(c) Cell wall material in fungi
(iii) Chitin
(d) Secondary metabolite
(iv) Collagen
Choose the correct option from the following
(a) (b) (c) (d)
(1) (iii) (iv) (i) (ii)
(2) (ii) (iii) (i) (iv)
(3) (ii) (iv) (iii) (i)
(4) (iii) (i) (iv) (ii)
104.Identify the substances having glycosidic bond and peptide bond, respectively in their structure
(a) Cellulose, lecithin
(b) Inulin, insulin
(c) Chitin, cholesterol
(d) Glycerol, trypsin
105.The enzyme enterokinase helps in conversion of
(a) caseinogen into casein
(b) pepsinogen into pepsin
(c) protein into polypeptides
(d) trypsinogen into trypsin
106.Which of the following are not secondary metabolites in plants?
(a) Rubber, gums
(b) Morphine, codeine
(c) Amino acids, glucose
(d) Vinblastin, curcumin
107.Which of the following RNAs is not required for the synthesis of protein?
(a) siRNA
(b) mRNA
(c) tRNA
(d) rRNA (smaller interference RNA
108.With regard to insulin choose correct options.
(a) C-peptide is not present in mature insulin.
(b) The insulin produced by rDNA technology has Cpeptide.
(c) The pro-insulin has C-peptide
(d) A-peptide and B-peptide of insulin are interconnected by disulphide bridges.
Choose the correct answer from the options given below
(1) (a) and (d) only
(2) (b) and (d) only
(3) (b) and (c) only
(4) (a), (c) and (d) only
109.Which of the following factors is not favourable for the formation of oxyhaemoglobin?
(a) High pO2
(b) Low Temperature
(c) Less H+ concentration
(d) High pCO2
110.Following are the statements with reference to ‘lipids’.
(a) Lipids having only single bonds are called unsaturated fatty acids
(b) Lecithin is a phospholipid.
(c) Trihydroxy propane is glycerol.
(d) Palmitic acid has 20 carbon atoms including carboxyl carbon.
(e) Arachidonic acid has 16 carbon atoms.
Choose the correct answer from the options given below.
(1) (b) and (e) only
(2) (a) and (b) only
(3) (c) and (d) only
(4) (b) and (c) only
Solutions
1.Solution: (a)
The two chains comprising the DNA are sprially coiled around a common axis to form a regular, right handed double helix.
2.Solution: (b)
In RNA, pyrimidine thymine is replaced by uracil.
3.Solution: (c)
The ratios for the (A+ G)/ (T+C) are constant at approximately 1.0 for the different organisms. Each of these organisms contains a double stranded genome. The percentage of Guanine and Cytosine are almost equal to each other, similarly the percentages of Adenine and
Thymine are almost equal to each other as well. In other words, the percentage of purines should be equal to the percentage of pyrimidines for double stranded DNA. This means that (A + G) = (C + T) The (A+T)/ (C + G) ratios are not constant. The relative numbers of (A + T) base pairs and
(G + C) base pairs are unique to each organism and can vary between the different species.
4.Solution: (c)
The nucleic acid (DNA and RNA) are repeating units of nucleotides i.e. polynucleotides. Each nucleotide comprises of nitrogenous heterocyclic bases viz. purines or pyrimidines, pentose sugar and phosphoric acid.
5.Solution: (d)
Cytochromes are a type of chromoproteins. Chromoproteins are conjugated proteins which are composed of a protein molecule joined to nonprotein group (Prosthetic group).
6.Solution: (d)
RNA is a single chain of ribonucleotides. Each ribonucleotide consists of nitrogenous bases (adenine, guanine, cytosine and uracil), ribose sugar and phosphoric acid.
7.Solution: (d)
Nucleic acid (DNA and RNA) comprises of polynucleotides. Each nucleotide consist of nitrogenous bases, pentose sugar and phosphoric acid.
8.Solution: (d)
According to Chargaff‘s rule, the amount of adenine is always equal to thymine and that of guanine equal to cytosine. Moreover, A + G = T + C. 120 + 120 = 120 + 120 240 = 240 So there will be 480 nucleotides in all.
9.Solution: (d)
DNA is a long, double helix consisting of repeating units of deoxyribonucleotides.
10.Solution: (b)
There are certain enzymes which have slightly different molecular structure but have similar catalytic function such enzymes are known as isoenzymes. Holoenzymes is the active compound formed by combination of a coenzyme and an apoenzyme. Apoenzyme is the protein
component of an enzyme, to which the coenzyme attaches to form an active enzyme. Coenzyme are organic non-protein molecules that bind with the protein molecule (apoenzyme) to form the active enzyme (holoenzyme).
11. Solution: (a)
The nitrogenous bases are constituents of DNA. The nitrogenous bases may be pruines or pyrimidines. Purines are 9 membered, double winged structures eg. adenine or guanine.
12.Solution: (d)
Water is the most abundant compound in the most majority of cells. About 65- 70% of human body is water. Major portion of water found in human body occurs in the cells as intracellular water.
13.Solution: (d)
An amino acid molecule consists of a central a carbon bonded to an amino group (–NH2), a carboxylic group (–COOH), a hydrogen atom and a carbon chain or ring on its sides.
14.Solution: (b)
Bulk of RNA occurs in the cytoplasm and a small amount in the nucleus in eukaryotic cells. In prokaryotic cell RNA is found in the cytoplasm.
15.Solution: (c)
Length of one helix is 34Å in B-DNA.
16.Solution: (d)
Enzymes accelerate chemical reaction by lowering the activation energy.
17.Solution: (c)
Principal or major elements include oxygen, carbon, hydrogen and nitrogen. They are so named because they alone constitute 99% of living system.
18.Solution: (a)
The pyrimidine bases include cytosine, thymine and uracil.
19. Solution: (d)
In a phosphodiester bond, linkage takes place between the phosphate group of one nucleotide and the hydroxyl group of sugar (ribose or deoxyribose) of the adjacent nucleotide.
20.Solution: (d)
Glycogen is a polysaccharide, which is synthesized and stored in the liver. It is released into the blood by breakdown of simple glucose, and energy is released.
21.Solution: (a)
The pyrenoids are small spherical protein bodies, surrounded by starch deposition found singly or in numbers embedded in
the chloroplast of many algae and bryophytes.
22.Solution: (c)
The nitrogenous bases forming the nucleoside in RNA are adenine, guanine (purines) and cytosine and uracil (pyrimidines).
23.Solution: (a)
Polysaccharides are complex carbohydrates formed by polymerization of a large number of units called monosaccharides, starch is a glucosan
polysaccharide and is the major reserve food of animals. Cellulose is the structural polysaccharide of plant cell wall. Sucrose is a disaccharide formed of one unit of Dglucose and one unit of D-fructose. Maltose is a disaccharide formed of two molecules of glucose held together, lactose is disaccharide formed through condensation of D-glucose and D-glucose. Glucose and fructose are monosaccharides.
24.Solution: (a)
Proteins are polymers of amino acids. There are only 20 amino acids which can be arranged in different orders in a polypeptide chain to form a wide array of proteins.
25.Solution: (b)
In bacteria the chromosome or nucleoid is a naked double stranded DNA. The bacterial DNA is folded with the help of RNAs forming a super coiled circular complex. The coiling is stabilized with the help of non-histonic polyamines and a number of positively changed ions.
Eukaryotic DNA is associated with histone proteins that are helpful in its coiling to form chromatin fibres.
26.Solution: (c)
In the cytoplasm protein synthesis is restricted to the ribosomes. Mitochondria being a semiautonomous organelle, has its own genetic machinery to synthesize its proteins.
27.Solution: (c)
Thymidine is used to assess the rate of DNA synthesis, since thymine is unique to DNA.
28.Solution: (b)
mRNA or messenger RNA brings coded information from DNA to form polypeptides. rRNA or ribosomal RNA occurs inside ribosomes and is involved in protein synthesis.
29.Solution (b) :
Heterochromatin is a specializedchromosome material which remains tightly coiled and stains darkly in interphase. Euchromatin is that portion of
the chromosome that stains with low intensity and uncoils during interphase. In the beginning of S-sphase, DNA replication occurs. DNA replication can occur in diffuse/ less tightly coiled euchromatin.
30.Solution: (c)
There are only 20 amino acids. These can be arranged in different order in the polypeptide chain to form a diverse array of proteins.
31.Solution: (c)
Cellulose is the structural polysaccharide of plant cell walls. They are long chain polymers of b-glucose units. The adjacent b-glucose units are joined by linkages.
32.Solution: (d)
Lactose is a disaccharide that consists of b-D-galactose and b-D-glucose molecules bonded through a b1-4 glycosidic linkage. Lactose makes up around 2-8% of the solids in milk. The name comes from the Latin word for milk, plus the -ose ending used to name sugars.
33.Solution: (a)
Gene mutation or point mutation is the change in expression of a gene caused by change in number sequence and types of nucleotides. A mutation from a wild gene type to a new type is called forward mutation. Reversal of mutated gene to wild type is reverse mutation. Chromosomal
mutations are changes in the morphology of chromosomes.
34.Solution: (d)
Secondary structure is development of new stearic relationships amongst the amino acids through formation of intra and inter
polypeptide hydrogen bonds.
35.Solution: (a)
36.Solution: (b)
Besides polypeptides, conjugated proteins posses additional groups, metals or ions. Nucleoproteins are proteins associated with nucleic acids. Lipoproteins are proteins associated with lipids. Chromoproteins are proteins associated with pigments. Glycoproteins are proteins having at their n- terminal and a simple or complex sugar residue.
37.Solution: (a)
Kim et al (1973) suggested L shape model of t- RNA by X-Ray diffraction while studying phenyl alanine t – RNA of yeast.
38.Solution: (a)
DNA and RNA are both polymers of nucleotides. DNA has deoxyribose sugar while RNA has ribose sugar. DNA has thymine while RNA has uracil in place of thymine.
39.Solution: (a)
40.Solution: (d)
Activation energy is the energy required to over come energy barrier of the reactants and make them reactive to start a chemical reaction. Enzymes lower the requirement of activation energy.
41.Solution: (d)
Essential amino acids are those which cannot be synthesized in the body from precursors. These amino acids must be present in our diet. They are Valine, Leucine, Isoleucine, Lysine, Methionine, Phenylalanine, Tryptophan and Threonine.
42.Solution: (c)
Ribozymes catalytically active RNA molecule discovered in 1980‘s are self splicing introns indicating their possible role as intermediates in the evolution of biological systems from abiotic substances.
43.Solution: (b)
Cellulose is the most abundant organic compound, most abundant polysaccharide and most abundant bipolymer found on earth.
44.Solution: (c)
Eukaryotes have three types of RNA polymerases: (i) RNA polymerase I – It is found in nucleus and is responsible for rRNA synthesis. (ii) RNA polymerase II – It is found in nucleoplasm and is responsible for m-RNA synthesis. (iii) RNA polymerase III-It is found in nucleoplasm and is
responsbile for t-RNA and 5-S RNA synthesis.
45.Solution: (d)
Erucic acid is a monounsaturated omega-9 fatty acid, denoted 22: 1 w-9. It is prevalent in rapeseed, wallflower seed, and mustard seed, making up 40 to 50 percent of their oils. Erucic acid is also known as cis-13- docosenoic acid and the trans isomer is known as brassidic acid.
46.Solution: (b)
Water attracting molecules are called hydrophilic. Water repelling molecules are called hydrophobic. Amino acids carry simultaneously positive and negative charges. Such substances are called zwitter ions. Lipids are compounds of C, H, O but the ratio of H and O is more than 2: 1 that
is the ratio of oxygen is lesser than carbohydrates. Lipids are insoluble in water but soluble in non-polar solvents such as benzene, chloroform etc. Commonest lipid found in a cell is phospholipid. It contains a hydrophilic (polar) head and a hydrophobic (nonpolar tail).
47.Solution: (a)
Reducing sugar is any sugar that has an aldehyde group or is capable of forming one in solution through isomerisation. Reducing monosaccharides include glucose, fructose, glyceraldehyde and galactose. Many disaccharides, like lactose and maltose also have a reducing form, as one of the two units may have an openchain form with an aldehyde group. However, sucrose and trehalose in which the anomeric carbons of the two units are linked together, are non reducing disaccharides since neither of the rings is capable of opening.
48.Solution: (a)
Collagen is a major fibrous protein of connective tissue occuring as white fibres produced by fibroblast.
49. Solution: (b)
Malignant cancer is caused by loss of control over cell‘s reproduction capacity. The cells undergo rapid division. Therefore, they are more easily damaged by radiations than normal cells.
50.Solution: (d)
Tyrosinase (polyphenol oxidase, catecholase) is a copper-containing oxidase which is widely distributed in plants, animals and man. It oxidizes tyrosine to the pigment melanin in mammals and causes the cut surfaces of many fruits and vegetables darken (browning reactions).
51.Solution: (d)
rRNA occurs inside ribosomes. m RNA brings information from DNA to polypeptides. hnRNA are heterogenous nuclear RNA.
52.Solution: (b)
In competitive inhibition the inhibitor resembles the substrate in structure and hence compete for the active site of the enzyme.
53.Solution: (c)
Km (Michealis Menten constant). It is defined as that substrate concentration at which under optimum conditions the rate of an enzyme catalysed reaction reaches half the maximum rate. Km is inversely proportional to affinity of enzyme for its substrate.
54.Solution: (a)
Help in regulating metabolism.
55.Solution: (c)
56. Solution: (c)
Endonucleases hydrolyse internal phosphodiester bonds in a polynucleotide chain (i.e. DNA). While exonucleases hydrolyse terminal phosphodiester bonds in a polynucleotide chain (i.e., DNA).
57.Solution: (a)
Antiparallel strands of DNA have two strands having phosphate groups at same positions in space.
58.Solution: (a)
Some bacteria (such as green Rhodopseudomonas ) algae and plants cell produces carbohydrates.
59.Solution: (d)
Coenzyme is an organic substance that enhances the action of an enzyme by binding with the protein molecule. Holoenzyme is a biochemically active compound formed by the combination of an enzyme with a coenzyme. Apoenzyme is the protein of an enzyme to which the coenzyme attaches to form an active enzyme Isoenzyme is one of the several forms of an enzyme that catalyse the same reaction but differ from each other in such properties as substrate affinity and maximum rates of enzyme substrate reaction.
60.Solution: (c)
It is calcium and phosphorus.
61.Solution: (a)
Malonate is a powerful inhibitor of cellular respiration, because it binds to the active site of the succinate dehydrogenase in the citric acid cycle but does not react, thereby competes with succinate, since it does not have the -CH2-CH2- group as in succinate which is required for dehydrogenation. For the oxidative phosphorylation reaction, malonate is an inhibitor for complex II which again contain succinate
dehydrogenase.
62.Solution: (a)
Massive ions like Na+ facilitate the absorption of substances like amino acid and glucose through Co transport.
63.Solution: (a)
64.Solution: (b)
65.Solution: (d)
66.Solution: (c)
Collagen is the most abundant protein of animal world. Rubisco (ribulose biphosphte carboxylase – oxygenase) is not only the most abundant protein in plants but also the whole biosphere.
67. Solution: (c)
The essential chemical components of many enzymes are vitamins, e.g., coenzyme nicotinamide adenine dinucleotide (NAD) and NADP contain vitamin niacin.
68.Solution: (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. Adenylic acid is a nucleotide consisting of adenine, ribose or deoxyribose, and a phosphate group. It is a constituent of DNA or RNA. It is also called adenosine monophosphate. Amino acids are organic acids (with carboxylic group COOH) having amino group (–NH2)
generally attached to Carbon or carbon next to carboxylic group. The carbon also bears a variable alkyl group (R) or hydrogen or hydrocarbon. In alanine is represented by methyl group.
69.Solution: (b)
A saturated or unsaturated fatty acid esterified to a glycerol molecule to which a phosphate group is also attached forms phosphoglycerides. Phosphoglycerides are major structural components of cell membranes. They are, therefore, also called membrane lipids. Lecithin is one example.
70.Solution: (c)
The essential chemical components of many enzymes are vitamins, e.g., coenzyme nicotinamide adenine dinucleotide (NAD) and NADP contain vitamin niacin.
71.Solution: (b)
Transition state structure formed during an enzymatic reaction is transient and unstable.
72.Solution: (d)
Chitin or fungal cellulose that is nitrogen containing polysaccharide and heteropolymer of NAG.
73.Solution: (c)
Almost all enzymes are proteins. There are some nucleic acids that behave like enzymes. There are called ribozyme (also called RNA enzyme or catalytic RNA).
74.Solution: (a)
75.(d) Only ii, iii and v
76.(b) Lipids are not polymers, because they are not built from monomers (units with similar composition)
77.(d) Tertiary structure or three dimensional structure of protein is stabilised by several types of bonds—hydrogen bonds, ionic bonds, Van der Waal’s interactions, covalent bonds and hydrophobic bonds.
78.(b) Glycine is a neutral amino acid. Cysteine and methionine are sulphur containing amino acid.
79.(b) Carbohydrates are commonly found as starch in plant storage organs. It is chemically non-reactive and osmotically inactive polysaccharides of much greater molecules weight. Carbohydrates performs a vital role in living organisms. Starch and other polysaccharides serve as energy storage in plants, particularly in seeds, tubers, etc. which provide a major energy source for animals, including humans.
80.(a) Most common monomer of Carbohydrate is glucose
81.(a) loosely attached organic part
82.(a) A typical fat molecule is a triglycerides & it is made up of one glycerol & three fatty acid molecules
83.(a) The chitinous exoskeleton of arthropods if formed by the polymerisation of N-acetyl glucosamine which is a derivative of glucose. It is alos a characteristic component of the cell wall of fungi, the tadulase of molluscs and the beaks and internal shells of cephalopods, including squid and octopuses.
84. (c) Casein is a storage protein. Lactose or milk sugar (a disaccharide) is a reducing sugar which is formed inside mammary glands by β -1, 4 condensation of two hexose molecules, glucose and galactose.
85.(b) With respect to enzyme action because addition of a lot of succinates reverses the inhibition of succinic dehydrogenase by malonate. Inhibition of succinic dehydrogenase by malonate ls an example of competitive inhibition Competitive inhibition occurs when enzyme and inhibition both have more or less similar structure and are present in higher concentration. Thus both enzyme and inhibitor compete for the active site of enzyme resulting in the decrease of the enzymatic activity.
86.(c) Rennin, helicase and hyaluronidase – Enzyme
87.(a) In the given question there are 4 pyrimidines as 2 cytosine and 2 thymine in option ‘a’.
88.(b) high , high
89.(c) Nucleosides are the structural subunit of nucleic acids such as DNA and RNA. A nucleoside, composed of a nucleobase, is either a pyrimidine (cytosine, thymine or uracil) or a purine (adenine or guanine), a five carbon sugar which is either ribose or deoxyribose.
90.(c) Phosphorus is present in plasma membrane in the form of phospholipid bilayer. It is an essential component of all nucleic acids not ‘certain’ nucleic acids. Moreover, phosphorus is never found in proteins.
91.(c) K m value
92.(b) cofactors of enzymes
93.(c) All those sugars which have free aldehyde or ketone group are called reducing sugars. These are able to reduce cupric ions (Cu2+) into cuprous ions (Cu+). Sucrose, starch are non reducing sugars.
94.(b) According to Erwin Chargaff, the base ratio A + T/G + C may vary from one species to another, but is constant for a given species. It is rarely equal to one and varies from 0.4 and 1.
95(a)Coenzymes are organic molecules that are nonproteins and mostly derivatives of vitamins soluble in water by phosphorylation; they bind apoenzyme protein molecule to produce active holoenzyme. Apoenzyme- An enzyme that requires a cofactor but does not have one bound. An apoenzyme is an inactive enzyme, activation of the enzyme occurs upon binding of an organic or inorganic cofactor. Holoenzyme- An apoenzyme together with its cofactor. A holoenzyme is complete and catalytically active. Most cofactors are not covalently bound but instead are tightly bound. However, organic prosthetic groups such as an iron ion or a vitamin can be covalently bound. Examples of holoenzymes include DNA polymerase and RNA polymerase which contain multiple protein subunits.
96(c)If the forming units of the given biological macromolecules are considered, proteins are formed of amino acids joined one after the other, polysaccharides are formed from monosaccharides, nucleic acids are formed of nucleotides. Only lipids are not made of uniform components, that is, they are not polymeric. They are tri-esters of fatty acids and glycerol.
97(c)Carbonyl and hydroxyl are the two main functional groups of sugars. The carbonyl and hydroxyl group present in all sugars. They are the basic components of sugars.
98 (c)Concanvalin A delayed regeneration and resulted in a abnormal. Amoirphous wall that was not readily digestible with gamete lytic enzyme.
99(2)A complete catalytically active enzyme with its bound prosthetic group is called holoenzyme. A prosthetic group is a tightly bound, specific non-polypeptide unit required for the biological function of some proteins. The prosthetic group may be organic like a vitamin, sugar, or lipid or inorganic like metal ion, but is not composed of amino acids
100 (d) Glucose transporter type 4 facilitated glucose transporter member 4, is a protein encoded, in humans, by the SLC2A4 gene. GLUT4 is the insulin-regulated glucose transporter found primarily in adipose tissues and striated muscle.
101(a)
Tyrosine— Aromatic amino acid
Glutamic Acid— Acidic amino acid
Lysine — Basic amino acid
Valine — Neutral amino acid
102(d)
Collagen is a protein made up of amino-acids, which are in turn built of carbon, oxygen and hydrogen. Collagen contains specific amino acids – Glycine, Proline, Hydroxyproline and Arginine. Collagen makes up approximately 30% of the proteins within the body. These are tough and strong structures found all over the body: in bones, tendons and ligaments. ollagen helps to give strength to various structures of the body and also protects structures like the skin by preventing absorption and spreading of pathogenic substances, environmental toxins, micro – organisms and cancerous cells. Collagen protein is the cement that holds everything together.
103(3)
• Inhibitor of catalytic activity —Malonate
• Possess peptide bonds — Collagen
• Cell wall material in fungi —Chitin
• Secondary metabolite — Ricin
104 (b)
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). This is a dehydration synthesis reaction (also known as a condensation reaction), and usually occurs between amino acids.
105 (d) The enzyme enterokinase helps in conversion of inactive trypsinogen into active trypsin.
106(c) Amino acids and Glucose are primary metabolites but not secondary metabolites as they have some known functions.
107 (a) siRNA are small interfering RNA also called silencing RNA. It is a class of double-stranded RNA, non-coding RNA molecules.
mRNA is messenger RNA that carries genetic information provided by DNA. tRNA carries amino acids to the mRNA during translation.
rRNA is structural RNA that forms ribosomes which are involved in translation.
108 (4)Cpeptide present in proinsulin is removed during its maturation. The insulin produced by rDNA technology has only A peptide and B peptide
109 (b) The factors favourable for the formation of oxyhaemoglobin at the alveolar level are; high pO2, low pCO2, less H+ concentration and lower
temperature. The conditions favourable for the dissociation of oxygen from oxyhaemoglobin at the tissue level are; low pO2 , high pCO2 , high H+ concentration and high temperature.
110 (4) Lecithin is a phospholipid. Glycerol is trihydroxy propane. Unsaturated fatty acids have double bonds in R group at one or more region
