CBSE Class 11 Biology Biomolecules MCQs

Question : A nucleotide is formed of

a) Nitrogen base, sugar and phosphate

b) Pyrimidine, sugar and phosphate

c) Purine, sugar and phosphate

d) Purine, pyrimidine and phosphate

Answer : Nitrogen base, sugar and phosphate

Question : Glycogen is a polymer of

a) glucose

b) sucrose

c) galactose

d) fructose

Answer : glucose

Question : Most abundant organic compound on earth is

a) Cellulose

b) Steroids

c) Protein

d) Lipids

Answer : Cellulose

Question : Protein synthesis in a cell takes place

a) in cytoplasm as well as in mitochondria

b) in the nucleolus as well as in cytoplasm

c) only on ribosomes attached to the nuclear envelope

d) only in the cytoplasm

Answer : in cytoplasm as well as in mitochondria

Question : In RNA, thymine is replaced by

a) Uracil

b) Guanine

c) Both

d) None of these

Answer : Uracil

Question :  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

Answer : amino acids and glucose

Question : An enzyme brings about

a) reduction in activation energy

b) increase in activation energy

c) increase in reaction time

d) decrease in reaction time

Answer : reduction in activation energy

Question : The enzymes hexokinase which catalyses glucose to glucose-6-phosphate in glycolysis is inhibited by glucose- 6-phosphate. This is an example of

a) feedback allosteric inhibition

b) non-competitive inhibition

c) competitive inhibition

d) None of these

Answer : feedback allosteric inhibition

Question : The enormous diversity of protein molecules is due mainly to the diversity of

a) amino acid sequences within the protein molecule

b) peptide bonds

c) R groups on the amino acids

d) amino groups on the amino acids

Answer : amino acid sequences within the protein molecule

Question : Length of one turn of the helix in a B-form DNA is approximately

a) 3.4 nm

b) 0.34 nm

c) Both

d) None of these

Answer : 3.4 nm

Question : Which of the following sets contains polysaccharides?

a) Starch, glycogen, cellulose

b) Sucrose, maltose, cellulose

c) Galactose, starch, sucrose

d) Glucose, fructose, lactose

Answer : Starch, glycogen, cellulose

Question : The most basic amino acid is

a) Arginine

b) Glycine

c) Histidine

d) Glutamine

Answer : Arginine

Question : The helical structure of protein is stabilized by

a) Hydrogen bonds

b) Disulphide bonds

c) Peptide bonds

d) None of these

Answer : Hydrogen bonds

Question : The Km value of the enzyme is the value of the substrate concentration at which the reaction reaches to

a) ½ Vmax

b) Zero

c) ¼ Vmax

d) 2 Vmax

Answer :  ½ Vmax

Question : Which group contains biocatalysts?

a) Peptidase, amylase, rennin

b) Glucose, amino acids, fatty acids

c) Rhodopsin, pepsin, steapsin

d) Myosin, oxytocin, adrenalin

Answer : Peptidase, amylase, rennin

Question : Enzymes that catalyse removal of groups from substrates by mechanisms other than hydrolysis, and addition of groups to double bonds, are called

a) lyases

b) dehydrogenases

c) Both

d) None of these

Answer : lyases

Question :  Oils are rich in

a) Fats that are generally liquid at room temperature

b) Glycerol that possesses three hydroxyl groups

c) Esters of fatty acids

d) Saturated fatty acids

Answer : Fats that are generally liquid at room temperature

Question : Bonds that do not exist in tertiary structure of proteins

a) Phosphodiester bonds

b) Hydrophobic etnractions

c) Ionic bonds

d) Covalent bonds

Answer : Phosphodiester bonds

Question : Cleavage of specific covalent bonds and removal of groups without hydrolysis is the property of

a) Lyases

b) Transferases

c) Isomerases

d) Hydrolases

Answer : Lyases

Question : Essential amino acids include

a) all of these

b) valine

c) leucine

d) tryptophan

Answer : all of these