NCERT Class 11-Biology Exemplar Chapter –9 Biomolecules Part 2

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Question 9:

A homopolymer has only one type of building block called monomer repeated ‘n’ number of times. A heteropolymer has more than one type of monomer. Proteins are heteropolymers made of aminoacids. While a nucleic acid like DNA or RNA is made of only 4 types of nucleotide monomers, proteins are made of

a. 20 types of monomers

b. 40 types of monomers

c. 3 types of monomers

d. only one type of monomer

Answer: (a)

Question 10:

Proteins perform many physiological functions. For example, some functions as enzymes. One of the following represents an additional function that some proteins discharge

a. Antibiotics

b. Pigment conferring colour to skin

c. Pigments making colours of flowers

d. Hormones

Answer: (d)

Question 11:

Glycogen is a homopolymer made of

a. Glucose units

b. Galactose units

c. Ribose units

d. Aminoacids

Answer: (a)

Question 12:

The number of ‘ends’ in a glycogen molecule would be

a. Equal to the number of branches plus one

b. Equal to the number of branch points

c. One

d. Two, one on the left side and another on the right side

Answer: (a)

Question 13:

A pure protein should normally have

a. Two ends

b. One end

c. Three ends

d. No ends

Answer: (a)

Question 14:

Enzymes are biocatalysts. They catalyse biochemical reactions. In general they reduce activation energy of reactions. Many physico-chemical processes are enzyme mediated. Some examples of enzyme mediated reactions are given below. Tick the wrong entry

a. Dissolving CO2 in water

b. Untwining the two strands of DNA

c. Hydrolysis of sucrose

d. Formation of peptide bond

Answer: (d)

Very Short Answer Type Questions

Question 1:

Medicines are either man made (i.e., synthetic) or obtained from living organisms like plants, bacteria, animals etc. and hence the latter are called natural products. Sometimes natural products are chemically altered by man to reduce toxicity or side effects. Write against each of the following whether they were initially obtained as a natural product or as a synthetic chemical.

a. Penicillin ___________________________

b. Sulfonamide ___________________________

c. Vitamin C ___________________________

d. Growth Hormone ___________________________

Answer:

A. Penicillin- Natural product (obtained from fungus P. notatum).

B. sulphonamide- Synthetic product

C. Vitamin C- Natural product

D. Growth Hormone- Natural product