Q9. The first amino acid in a polypeptide chain is called the:
Correct Answer: (c)
The first amino acid is the N-terminal and the last is the C-terminal.
Q10. Proteins are described as ______ of amino acids.
Correct Answer: (b)
As there are 20 types of amino acids, a protein is a heteropolymer and not a homopolymer.
Q11. Which of the following is a basic amino acid?
Correct Answer: (b)
Lysine is a basic amino acid, while Glutamic acid is acidic and Valine is neutral.
Q12. Lecithin is an example of a:
Correct Answer: (c)
Phospholipids are found in cell membranes; Lecithin is one example.
Q13. Regarding the Fluid Mosaic Model: (i) Proposed by Singer and Nicolson in 1972. (ii) Quasi-fluid nature of lipid enables lateral movement of proteins. (iii) Fluidity is important for cell division and secretion.
Correct Answer: (a)
As stated in section 8.5.1 of the provided text.
Q14. Match the polysaccharide with its source:
Polysaccharide
Source
A. Starch
(I) Exoskeleton of Insects
B. Cellulose
(II) Liver/Muscle
C. Glycogen
(III) Plant tissues
D. Chitin
(IV) Cotton fibre
Correct Answer: (a)
Correct sources mentioned in section 9.5 and 9.6.
Q15. The rate of a physical or chemical process doubles or decreases by half for every ______ change in temperature.
Correct Answer: (b)
A general rule of thumb is that rate changes by factor of 2 for every 10°C change.
Q16. The non-protein constituent bound to an enzyme to make it active is called a:
Correct Answer: (b)
Non-protein constituents called co-factors are bound to enzymes to make them catalytically active.
Q17. The fraction obtained during chemical analysis that remains on the cheesecloth is called:
Correct Answer: (c)
The fraction that does not pass through the cloth is the retentate or acid-insoluble fraction.
Q18. Match the base with its type:
Column I
Column II
A. Adenine
(I) Pyrimidine
B. Guanine
(II) Purine
C. Cytosine
(III) Purine
D. Uracil
(IV) Pyrimidine
Correct Answer: (a)
Adenine/Guanine are purines; Cytosine/Uracil/Thymine are pyrimidines.
Q19. Regarding enzyme inhibition, which are correct? (i) Malonate is a competitive inhibitor. (ii) It inhibits succinic dehydrogenase. (iii) It resembles succinate in structure. (iv) Competitive inhibitors are used to control bacterial pathogens.
Correct Answer: (a)
Full mechanism described in section 9.8.4.
Q20. Amino acids are organic compounds containing an amino group and an acidic group on the:
Correct Answer: (b)
Amino acids contain an amino and acidic group on the same carbon, the alpha-carbon.
Q21. Match the co-factor with its specific example:
Column I
Column II
A. Prosthetic group
(I) NAD / NADP
B. Co-enzyme
(II) Zinc
C. Metal ion
(III) Heme
Correct Answer: (a)
Zinc is a metal ion; Heme is prosthetic; NAD is a co-enzyme.
Q22. How many carbons, including the carboxyl carbon, are present in Palmitic acid?
Correct Answer: (a)
Palmitic acid has 16 carbons including carboxyl carbon.
Q23. Assertion: Secondary metabolites like alkaloids and rubber are useful to human welfare.
Reason: Their role in host organisms is clearly understood in all cases.
Correct Answer: (c)
We do not yet understand the role of all secondary metabolites in host organisms.
Q24. Match the amino acids in Column I with their nature in Column II:
Q25. Assertion: The zwitterionic form of amino acids changes with pH.
Reason: The amino and carboxyl groups in amino acids are ionizable.
Correct Answer: (a)
Ionization depends on the H+ concentration of the solution.
Q26. Assertion: Enzymes are damaged at high temperatures (above 40°C).
Reason: Proteins are denatured by heat.
Correct Answer: (a)
Heat disrupts the tertiary structure of proteins, leading to loss of function.
Q27. Match the elements with % weight in Earth's crust:
Element
% Weight
A. Silicon
(I) 46.6
B. Oxygen
(II) 27.7
C. Nitrogen
(III) very little
Correct Answer: (a)
Data from Table 9.1.
Q28. Match the lipid with its structure:
Lipid
Structure
A. Glycerol
(I) Phosphorylated organic compound
B. Phospholipid
(II) Trihydroxy propane
C. Palmitic acid
(III) 20 Carbons
D. Arachidonic acid
(IV) 16 Carbons
Correct Answer: (a)
Definitions from section 9.1.
Q29. Adult human haemoglobin consists of how many subunits?
Correct Answer: (c)
Adult human Hb consists of 4 subunits (two alpha and two beta).
Q30. Which vitamin is present in co-enzymes NAD and NADP?
Correct Answer: (c)
NAD and NADP contain the vitamin niacin.
Q31. Regarding protein functions: (i) Some transport nutrients across membranes. (ii) Some act as intercellular ground substance. (iii) Some fight infectious agents.
Correct Answer: (a)
Functions listed in Table 9.5 and section 9.4.
Q32. Assertion: Cellulose does not give a blue colour with Iodine.
Reason: Cellulose does not contain complex helices to hold Iodine molecules.
Correct Answer: (a)
Unlike starch, cellulose lacks the helical structure needed to trap iodine.
Q33. A fatty acid is said to be unsaturated if it has:
Correct Answer: (b)
Fatty acids could be saturated (no double bonds) or unsaturated (one or more C=C double bonds).
Q34. Which are correct regarding Nitrogen bases? (i) Purines have two rings (Skeletal heterocyclic ring). (ii) Uracil is a purine. (iii) Thymine is found in DNA. (iv) Nitrogen bases are found in the acid-insoluble fraction only.
Correct Answer: (a)
Uracil is a pyrimidine. Free bases are found in the soluble pool as they are micromolecules.
Q35. The most abundant protein in the whole of the biosphere is:
Correct Answer: (c)
RuBisCO is the most abundant protein in the biosphere; Collagen is most abundant in the animal world.
Q36. Chemically, amino acids are considered as substituted:
Correct Answer: (b)
Amino acids are called substituted methanes because four groups occupy the four valency positions of the carbon.
Q37. Regarding the zwitterionic form of an amino acid: (i) It has both positive and negative charges. (ii) It exists at a specific pH. (iii) It is formed due to the ionization of amino and carboxyl groups.
Correct Answer: (a)
Zwitterion (B) in Figure 9.1 shows both charges due to ionization.
Q38. Assertion: Adenine and Guanine are purines.
Reason: They are substituted pyrimidines.
Correct Answer: (c)
Adenine and Guanine are purines; Cytosine, Uracil and Thymine are pyrimidines.
Q39. Exoskeletons of arthropods have a complex polysaccharide called:
Correct Answer: (b)
Exoskeletons of arthropods are made of chitin.
Q40. Which of the following is a 'trihydroxy propane'?
Correct Answer: (b)
Glycerol is a simple lipid known as trihydroxy propane.
Q41. Match the compounds in Column I with their molecular description in Column II:
Column I
Column II
A. Acid-soluble pool
(I) Proteins, Nucleic acids, Polysaccharides
B. Acid-insoluble fraction
(II) Thousands of organic compounds
C. Micromolecules
(III) Weights 18 to 800 Da
D. Biomacromolecules
(IV) Weights > 10,000 Da
Correct Answer: (a)
Correct distribution between soluble/insoluble and weight classes.
Q42. Which of the following are characteristics of amino acids? (i) They are $\alpha$-amino acids. (ii) They are substituted methanes. (iii) Only 20 types occur in proteins. (iv) The R group in serine is a methyl group.
Correct Answer: (a)
The R group in serine is hydroxy methyl; alanine has the methyl group.
Q43. Enzymes lower the ______ to make the transition of S to P easy.
Correct Answer: (b)
Enzymes bring down the activation energy barrier.
Q44. The zwitterionic form of an amino acid exists because of:
Correct Answer: (b)
The ionizable nature of amino and carboxyl groups allows the structure to change at different pH levels, forming a zwitterion.
Q45. Match the catalytic steps in order:
Step
Action
A. Step 1
(I) Breakage of chemical bonds
B. Step 2
(II) Release of product
C. Step 3
(III) Substrate binds to active site
D. Step 4
(IV) Enzyme alters shape
Correct Answer: (a)
Order of catalytic cycle as per section 9.8.3.
Q46. Assertion: Inorganic catalysts differ from enzymes.
Reason: Inorganic catalysts work efficiently at high temperatures and pressures.
Correct Answer: (a)
Enzymes (biocatalysts) are sensitive to temperature, whereas inorganic ones are not.
Q47. Enzymes isolated from ______ organisms are thermally stable up to 80-90°C.
Correct Answer: (c)
Enzymes from thermophilic organisms are stable at high temperatures.
Q48. Assertion: Competitive inhibitors are used to control bacterial pathogens.
Reason: They inhibit specific enzymes required by the pathogen by competing with its substrate.
Correct Answer: (a)
Competitive inhibition prevents the actual substrate from binding, halting the reaction.
Q49. Match the following for Cell Composition:
Component
% of total cellular mass
A. Water
(I) 10-15
B. Proteins
(II) 70-90
C. Nucleic acids
(III) 5-7
D. Carbohydrates
(IV) 3
Correct Answer: (a)
Data from Table 9.4.
Q50. When a nitrogenous base is attached to a sugar, it is called a:
Correct Answer: (b)
Nitrogen bases attached to a sugar are called nucleosides.
Q51. Assertion: Starch forms helical secondary structures.
Reason: Starch is a variant of cellulose and serves as a storehouse of energy in plant tissues.
Correct Answer: (b)
Both are true, but being an energy storehouse doesn't explain why it forms a helix.
Q52. Which of the following is correct? (i) Adult human Hb has 4 subunits. (ii) Collagen is the most abundant animal protein. (iii) RuBisCO stands for Ribulose bisphosphate Carboxylase-Oxygenase.
Correct Answer: (a)
Information found in sections 9.4 and 9.7.
Q53. Which of the following is true for protein structure? (i) Primary structure is a sequence of amino acids. (ii) Secondary structure only contains left-handed helices. (iii) Tertiary structure is like a hollow woolen ball. (iv) Quaternary structure involves assembly of multiple subunits.
Correct Answer: (a)
In proteins, only right-handed helices are observed, not left-handed.
Q54. Assertion: Ribozymes are enzymes.
Reason: All enzymes are proteins.
Correct Answer: (c)
Ribozymes are nucleic acids that act as enzymes, proving not all enzymes are proteins.
Q55. Match the following structural features of proteins:
Column I
Column II
A. Primary
(I) Hollow woolen ball
B. Secondary
(II) Positional info/Line
C. Tertiary
(III) Assembly of subunits
D. Quaternary
(IV) Helix/Revolving staircase
Correct Answer: (a)
Visual descriptions of protein hierarchy levels.
Q56. Identify the correct statements regarding Starch: (i) It is a storehouse of energy in plant tissues. (ii) It forms helical secondary structures. (iii) It can hold Iodine molecules in its helical portion. (iv) It gives a red colour with iodine.
Correct Answer: (a)
Starch-I2 is blue in colour, not red.
Q57. Assertion: The primary structure of a protein gives its positional information.
Reason: It specifies which amino acid is first, second, and so on.
Correct Answer: (a)
Sequence determines the identity and position.
Q58. An active site of an enzyme is a ______ into which the substrate fits.
Correct Answer: (b)
An active site is a crevice or pocket into which the substrate fits.
Q59. Which of the following is correct regarding the 'acid-insoluble fraction'? (i) It contains proteins and nucleic acids. (ii) It contains lipids. (iii) It contains polysaccharides. (iv) All compounds except lipids have molecular weights above 10,000 Da.
Correct Answer: (c)
Section 9.3 explicitly lists these four types in the insoluble fraction.
Q60. Enzymes that catalyse the linking together of two compounds are called:
Correct Answer: (b)
Ligases catalyze the linking together of 2 compounds.
Q61. Malonate inhibits succinic dehydrogenase because it resembles:
Correct Answer: (b)
Malonate is a competitive inhibitor that closely resembles the substrate succinate.
Q62. Regarding Amino acid groups: (i) Lysine is basic. (ii) Valine is neutral. (iii) Glutamic acid is acidic. (iv) Alanine is aromatic.
Correct Answer: (a)
Alanine is a neutral amino acid with a methyl R group; Tyrosine is aromatic.
Q63. Which statements about enzymes are correct? (i) They are damaged at high temperatures above 40°C. (ii) They increase the rate of reactions by millions of times. (iii) They work by increasing the activation energy. (iv) They possess an active site.
Correct Answer: (a)
Enzymes lower the activation energy, not increase it.
Q64. Regarding the structure of DNA and RNA, which statements are true? (i) DNA contains deoxyribose sugar. (ii) RNA contains ribose sugar. (iii) Both are made up of nucleotides only. (iv) Nitrogen bases are heterocyclic compounds.
Correct Answer: (a)
All these facts are stated in section 9.6.
Q65. The most abundant chemical in living organisms is:
Correct Answer: (b)
Water makes up 70-90% of total cellular mass.
Q66. Match the metabolic products under different conditions in pathway:
Condition
Product
A. Skeletal muscle (Anaerobic)
(I) Pyruvic acid
B. Normal Aerobic
(II) Lactic acid
C. Yeast fermentation
(III) Ethanol
Correct Answer: (a)
Different products based on conditions for pyruvic acid pathway.
Q67. Assertion: Water is the most abundant chemical in living organisms.
Reason: It occupies 70-90% of total cellular mass.
Correct Answer: (a)
Percentage by mass directly defines abundance.
Q68. Inulin is a polymer of:
Correct Answer: (b)
Inulin is a polymer of fructose.
Q69. Which of the following is a nucleotide?
Correct Answer: (c)
Adenosine is a nucleoside; Adenylic acid is a nucleotide (base + sugar + phosphate).
Q70. In the absence of any enzyme, the formation of H2CO3 is about ______ molecules per hour.
Correct Answer: (a)
Without enzymes, only 200 molecules of H2CO3 are formed in an hour.
Q71. Statements about co-factors: (i) Apoenzyme is the protein part of the enzyme. (ii) Prosthetic groups are tightly bound to apoenzyme. (iii) Co-enzymes association is only transient. (iv) Catalytic activity is retained even if co-factor is removed.
Correct Answer: (a)
Activity is lost if the co-factor is removed.
Q72. Assertion: Zinc is a co-factor for the enzyme carboxypeptidase.
Reason: It is a prosthetic group tightly bound to the apoenzyme.
Correct Answer: (c)
Zinc is a metal ion co-factor, not a prosthetic group. Heme is an example of a prosthetic group.
Q73. Correct statements about Polysaccharides: (i) They are long chains of sugars. (ii) They are like cotton threads. (iii) Building blocks are monosaccharides. (iv) They are found in the acid-soluble pool.
Correct Answer: (a)
Polysaccharides are macromolecules found in the acid-insoluble fraction.
Q74. Assertion: The blood of humans contains 52% proteins and 40% lipids.
Reason: This ratio is constant for all cell types.
Correct Answer: (c)
The ratio of protein and lipid varies considerably in different cell types.
Q75. Match the Secondary Metabolites in Column I with their category in Column II:
Q76. Select the correct statements regarding Secondary Metabolites: (i) They are found in plant, fungal and microbial cells. (ii) Alkaloids, flavonoids, and rubber are examples. (iii) They always have identifiable functions in host organisms. (iv) Many are useful to human welfare.
Correct Answer: (a)
We do not understand the role or functions of all secondary metabolites in host organisms.
Q77. Identify the correct enzyme class descriptions: (i) Isomerases catalyze inter-conversion of optical isomers. (ii) Lyases catalyze removal of groups leaving double bonds. (iii) Ligases catalyze hydrolysis of bonds.
Correct Answer: (a)
Ligases catalyze joining/linking, while Hydrolases catalyze hydrolysis.
Q78. Assertion: The catalytic activity of an enzyme is lost when the co-factor is removed.
Reason: Co-factors play a crucial role in the catalytic activity of the enzyme.
Correct Answer: (a)
Activity depends on the complete holoenzyme structure.
Q79. Assertion: Chitin is a homopolymer.
Reason: It is found in the exoskeletons of arthropods.
Correct Answer: (b)
Both are true, but the location (exoskeleton) doesn't explain the chemical nature (homopolymer).
Q80. Assertion: A protein is a heteropolymer.
Reason: It is made of only one type of amino acid monomer.
Correct Answer: (c)
Proteins are heteropolymers because they are made of 20 different types of amino acids.
Q81. Which element's relative abundance is higher in living organisms compared to the earth's crust?
Correct Answer: (c)
Relative abundance of carbon and hydrogen is higher in any living organism than in earth’s crust.
Q82. Match the carbohydrate with its monomer or type:
Column I
Column II
A. Cellulose
(I) Fructose polymer
B. Inulin
(II) Glucose homopolymer
C. Glycogen
(III) Nitrogen containing glucose derivative
D. Chitin
(IV) Animal variant of starch
Correct Answer: (a)
Based on section 9.5 and 9.6.
Q83. Nucleic acids that behave like enzymes are called:
Correct Answer: (b)
There are some nucleic acids that behave like enzymes; these are called ribozymes.
Q84. Which of the following is NOT a polymer?
Correct Answer: (d)
Molecules in the insoluble fraction with the exception of lipids are polymeric substances.
Q85. Assertion: Lipids are not strictly macromolecules.
Reason: Their molecular weight does not exceed 800 Da.
Correct Answer: (a)
Lipids have low molecular weight but appear in the macromolecular fraction due to vesicle formation.
Q86. Identify correct statements for Lipids: (i) They are generally water insoluble. (ii) Glycerol is trihydroxy propane. (iii) Lecithin is a simple lipid. (iv) Neural tissues have complex lipids.
Correct Answer: (a)
Lecithin is a phospholipid (complex lipid), not a simple lipid.
Q87. To analyze organic compounds in living tissue, it is grinded in which acid?
Correct Answer: (b)
Living tissue is ground in trichloroacetic acid (Cl3CCOOH) to perform chemical analysis.
Q88. Compounds found in the acid-soluble pool have molecular weights ranging from:
Correct Answer: (a)
The acid soluble pool contains compounds with weights from 18 to around 800 daltons.
Q89. Assertion: Polysaccharides are homopolymers in most cases.
Reason: They are made of different types of monosaccharides.
Correct Answer: (c)
A homopolymer is made of only one type of monomer, which is the definition of most polysaccharides in nature according to the text.
Q90. Identify the correct definitions for carbohydrate variants: (i) Glycogen has a reducing end (right) and a non-reducing end (left). (ii) Starch is the store house of energy in plant tissues. (iii) Glycogen is the energy store in animals. (iv) Cellulose is a heteropolymer.
Correct Answer: (a)
Cellulose is a homopolymer of glucose.
Q91. Which are correct for fatty acids? (i) Palmitic acid has 16 carbons. (ii) Arachidonic acid has 20 carbons. (iii) Carboxyl carbon is excluded from the count.
Correct Answer: (a)
Carboxyl carbon is included in the count.
Q92. Assertion: Tertiary structure is absolutely necessary for the biological activities of proteins.
Reason: It brings distant amino acid side chains close together to form active sites.
Correct Answer: (a)
The folding in tertiary structure creates the crevices/pockets that serve as active sites.
Q93. In the amino acid Glycine, the 'R' group is replaced by:
Correct Answer: (c)
In glycine, the R group is a hydrogen.
Q94. Which protein structure provides a 3-dimensional view and is necessary for biological activity?
Correct Answer: (c)
Tertiary structure gives a 3-dimensional view and is absolutely necessary for biological activities.
Q95. Which of the following is a secondary metabolite used as a drug?
Correct Answer: (b)
Table 9.3 lists Vinblastin and curcumin as drugs.
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