This set of Class 11 Biology Chapter 9 Multiple Choice Questions & Answers (MCQs) focuses on “Biomolecules – Concept of Metabolism – 2”.
1. Which of these is mandatory for all metabolic reactions?
a) Breakdown of biomolecules
b) Synthesis of biomolecules
c) Presence of inhibitor
d) Presence of catalyst
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Explanation: Metabolic reactions may involve either the synthesis or breakdown of biomolecules through the processes of anabolism or catabolism, respectively. However, all reactions have a catalyst.
2. Which of these statements is true about metabolism?
a) Metabolic pathways are always circular
b) Metabolic pathways are always linear
c) All metabolic reactions are catalyzed
d) The level of metabolites is always constant
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Explanation: Metabolic pathways can be both circular and linear in nature. Due to metabolism, all biomolecules have a turnover and their levels are not constant. All metabolic reactions are catalyzed.
3. Which of these is a physical process?
a) Combustion of hydrocarbons
b) Curdling of milk
c) Dissolving carbon dioxide in water
d) Rusting of iron
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Explanation: Dissolution of carbon dioxide in water is an example of a physical process. It is reversible. The combustion of hydrocarbons, curdling of milk and rusting of iron are chemical processes.
4. Catalysts that enhance the rate of metabolic reactions are _____
a) proteins
b) lipids
c) lipoproteins
d) polysaccharides
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Explanation: Catalysts enhance the rate of a chemical reaction without getting depleted. All metabolic reactions taking place inside the body involve the presence of a catalyst. They are proteins.
5. Enzymes are _____
a) lipids
b) proteins
c) polysaccharides
d) lipoproteins
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Explanation: Enzymes are biological catalysts that enhance the rate of a metabolic reaction. All metabolic reactions taking place inside the body involve the use of enzymes. Enzymes are proteinaceous.
6. Which of these are biocatalysts?
a) Neurotransmitters
b) Hormones
c) Enzymes
d) Trace elements
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Explanation: Biocatalysts are substances that speed up or catalyze the rate of metabolic reactions. Enzymes are known as biocatalysts as they speed up metabolic reactions without getting depleted. They are proteins.
7. Which of these is true about enzymes?
a) All enzymes have catalytic power
b) Enzymes are active at high temperatures
c) Enzymes are carbohydrates
d) Enzymes often get depleted
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Explanation: Enzymes are biocatalysts that are protein in nature. They are active at room temperature and get denatured at high temperatures. Their levels or amounts remain constant in the body.
8. Which of these is an example of anabolism?
a) Glucose to pyruvate
b) Glucose to lactic acid
c) Glycogen to glucose
d) Acetic acid to cholesterol
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Explanation: Anabolism is a type of metabolism which involves the biochemical synthesis of larger biomolecules from smaller ones. Hence, the formation of cholesterol from acetic acid is an example of anabolism.
9. Which of these is an example of catabolism?
a) Glucose to glycogen
b) Acetic acid to cholesterol
c) Glucose to pyruvate
d) Amino acids to polypeptides
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Explanation: Catabolism is a type of metabolism which involves the biochemical breakdown of larger biomolecules to smaller ones. Hence, the breakdown of glucose to pyruvate is an example of catabolism.
10. The dissolution of carbon dioxide in water is a catalyzed reaction in the body. True or false?
a) True
b) False
View Answer
Explanation: All metabolic reactions taking place inside the body are catalyzed. Hence, the dissolution of carbon dioxide for transport throughout the body also involves the presence of a catalyst.
11. Which of these processes require energy?
a) Formation of acetic acid from cholesterol
b) Formation of glucose from glycogen
c) Formation of pyruvate from glucose
d) Formation of protein from amino acids
View Answer
Explanation: The conversions of glucose to pyruvate, glycogen to glucose and cholesterol to acetic acid are catabolic processes. The formation of proteins from amino acids is an anabolic process and requires energy input.
12. Which of these processes liberate energy?
a) Formation of protein from amino acids
b) Formation of glycogen from glucose
c) Formation of lactic acid from glucose
d) Formation of cholesterol from acetic acid
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Explanation: The conversions of amino acids to proteins, glucose to glycogen and acetic acid to cholesterol are anabolic processes. The formation of lactic acid from glucose is a catabolic process and liberates energy.
13. How many steps are involved in the conversion of glucose to lactic acid?
a) 4
b) 6
c) 10
d) 12
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Explanation: The conversion of glucose to lactic acid is a catabolic process. It involves the release of energy. The larger glucose molecule is metabolically broken down into lactic acid molecules by glycolysis.
14. What is the full form of ATP?
a) Adenosine triphosphate
b) Adenine triphosphatase
c) Adenyl triphosphatase
d) Adreno triphosphate
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Explanation: The full form of ATP id adenosine triphosphate. It is the energy currency of the cell. It is found in all living organisms. The energy is derived from the bond energy present in the ATP molecule.
15. Where does glucose get converted to lactic acid in the body?
a) Liver
b) Skeletal muscles
c) Spleen
d) Stomach
View Answer
Explanation: Lactic acid is formed in the skeletal muscles by the incomplete breakdown of glucose by the process of catabolism. It occurs due to low levels of oxygen, which is required for the breakdown of glucose.
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