This set of Class 11 Biology Chapter 9 Multiple Choice Questions & Answers (MCQs) focuses on “Biomolecules – Primary and Secondary Metabolites – 2” for Medical Entrance Exams.
1. Based on which of the following, amino acids are classified?
a) Based on the number of hydrogen
b) Based on the number of carbon atoms
c) Based on the number of ions
d) Based on the number of amino and carboxyl groups
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Explanation: Based on the number of amino and carboxyl groups, there are acidic (e.g., glutamic acid, aspartic acid), basic (lysine, arginine) and neutral (valine) amino acids. Similarly, there are aromatic amino acids like phenylalanine, etc.
2. Which of the following is a peculiar property of amino acids?
a) Basic nature
b) Acidic nature
c) Ionisable nature
d) Neutral nature
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Explanation: A peculiar property of amino acids is the ionisable nature of –NH2 and –COOH groups. Hence, in solutions of different pHs, the structure of amino acid changes.
3. What does the given structure represent?
a) Glycine
b) Serine
c) Thymine
d) Lysine
View Answer
Explanation: The given structure represents glycine. Glycine is a neutral amino acid. It is the only optically inactive amino acid. It is also responsible for the heme formation.
4. How many fractions do we obtain while straining a thick slurry of living tissue through the cheesecloth?
a) One
b) Two
c) Three
d) Four
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Explanation: When we strain thick slurry through a cheesecloth or cotton we would obtain two fractions. One is called the filtrate or the acid-soluble pool, and the second, the retentate or the acid-insoluble fraction.
5. All the elements present in a sample of earth’s crust are also present in a sample of living tissue.
a) True
b) False
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Explanation: All the elements present in a sample of earth’s crust are also present in a sample of living tissue. However, a closer examination reveals that the relative abundance of carbon and hydrogen with respect to other elements is higher in any living organism than in earth’s crust.
6. What are the primary metabolites?
a) Compounds formed in every kind of cells
b) Compounds present in only plants
c) Compounds formed only in animals
d) Compounds formed only by fungus
View Answer
Explanation: The compounds which are involved in the metabolic or the physiologic activities of the cell and which are formed in all kinds of cells are called primary metabolites.
7. What are the secondary metabolites?
a) Compounds formed in all kinds of cells
b) Compounds formed only in plants
c) Compounds formed only in animals
d) By-products of the cell
View Answer
Explanation: Secondary metabolites are not involved in metabolic reactions. We do not understand the role or functions of all the secondary metabolites in the host organism. Secondary metabolites are the by-products of various cells.
8. Which of the following cells are not responsible for the formation of secondary metabolites?
a) Plant cells
b) Fungal cells
c) Animal cells
d) Bacterial cells
View Answer
Explanation: Secondary metabolites are not the by-products of animal cells. These metabolites have ecological importance. Plant cells, Fungal cells and bacterial cells are responsible for the formation of secondary metabolites.
9. Which of the following is not a secondary metabolite?
a) Amino acids
b) Gum
c) Perfume
d) Spices
View Answer
Explanation: Rubber, drugs, spices, gum, perfumes and pigments are some of the secondary metabolites. Many of these secondary metabolites are useful to human welfare. Glucose, amino acids, fructose, vitamins, cholesterol are some of the primary metabolites.
10. Which of the following is not a polymeric substance?
a) Rubber
b) Gum
c) Cellulose
d) Morphine
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Explanation: Rubber, gum and cellulose are polymeric substances. Morphine, codeine, etc. are some of the alkaloids. Both the alkaloids and polymeric substances are some of the secondary metabolites.
11. Carotenoids and anthocyanins are some of the primary metabolites.
a) True
b) False
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Explanation: Carotenoids and anthocyanins are some of the types of pigments. Pigments are included in the secondary metabolites. For example, chlorophyll is the major pigment responsible for trapping light.
12. Which of the following is an essential oil?
a) Monoterpene
b) Lemongrass oil
c) Vinblastin
d) Abrin
View Answer
Explanation: Lemongrass oil is an essential oil. Monoterpenes, Diterpenes are some examples of terpenoids. Vinblastin, curcumin are examples of some drugs. Abrin and ricin are examples of toxins. All of these are examples of secondary metabolites.
13. Mitochondria are rich in which of the following ions?
a) Manganese
b) Molybdenum
c) Copper
d) Nitrogen
View Answer
Explanation: Mitochondria are rich in manganese. Molybdenum is necessary for fixation of nitrogen, catalysed by the enzyme nitrogenase. Copper occurs in cytochrome oxidase.
14. Which of the following is the most abundant element in the cell?
a) Oxygen
b) Iron
c) Magnesium
d) Copper
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Explanation: The most abundant element in the cell or living matter is oxygen. Fe2+ and Cu2+ are found in cytochromes. Magnesium is essential for a large number of enzymes, particularly those utilising ATP.
15. Which of the following is incorrect regarding sodium and potassium ions?
a) Responsible for maintenance of extracellular and intracellular fluids
b) Responsible for transmission of electrical impulses
c) Responsible for the maintenance of membrane potential
d) Responsible for nitrogen fixation in animals
View Answer
Explanation: Sodium and Potassium are responsible for the maintenance of extracellular and intracellular fluids through the osmotic effects of the concentration of these two ions. These two ions are also responsible for the maintenance of membrane potential and the transmission of electrical impulses in the nerve cells.
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