FREE NEET Biology Practice MCQ Test: Biomolecules Exercise 1 Questions Answers With Detailed Explanations [PDF]

Answer: (b)

Transition state is formation of unstable intermediate structural state. During this, substrate bonds are broken and new bonds are established that transform the substrate molecules into products. This state is transient and highly unstable.

Answer: (a)

Coenzyme is the non protein organic group which gets attached to the apoenzyme to form holoenzyme or conjugate enzyme. It helps in removing a product of chemical reaction besides bringing contact between the substrate and the enzyme. Most of the coenzymes are made of water soluble vitamins B and C, e.g., thiamine, riboflavin, nicotinamide, pyridoxine.

Answer: (a)

Answer: (a)

In DNA purine nitrogen bases are Guanine and Adenine.

Answer: (b)

Answer: (b)

A nucleoside is pentose sugar and base together, without the phosphate group. Uracil is present as uridine in RNA only.

Uracil + Ribose → Uridine

Answer: (b)

Answer: (c)

Enzymes increase the rate of reaction without being consumed in the reaction.

Answer: (a)

Answer: (a)

Answer: (d)

Answer: (a)

Answer: (b)

As the 1st carbon of glucose and 2nd carbon of fructose are combined, the anomeric carbon atoms of both are not available for the reduction property.

Answer: (a)

Enzymes having slightly different molecular structures but performing identical activities are called isoenzymes. Over 100 enzymes are known to have isoenzymes. Thus α-amylase of wheat endosperm has 16 isozymes, lactic dehydrogenase has 5 isoenzymes in man.

Answer: (d)

Answer: (b)

The function and shape of a protein is affected by sequence of 20 types of amino acids, each having an amino group –$NH_{2}$, a carboxylic acid group –COOH, a hydrogen atom each attached to carbon located next to –COOH group and a side chain R which varies from one amino acid to other. (It can be hydrogen or an aliphatic group, an aromatic or heterocyclic group).

Answer: (c)

Glycosidic bonds are bonds established between aldose or ketose group of carbohydrate with alcoholic or nitrogen group of another organic compound.Two amino acid molecules can be covalently joined through a substituted amide linkage, termed a peptide bond.

Answer: (a)

Quaternary structure is the three-dimensional structure of a multi-subunit protein. For a protein to have a quaternary structure, it must consist of two or more polypeptide subunits.

Answer: (c)

Prosthetic group is an organic substances which is dialyzable, thermostable and firmly attached to the protein or apoenzyme portion during the complete catalytic cycle. Apoenzyme is a protein that forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate.

Answer: (d)

Tertiary structure or three dimensional structure of protein is stabilised by several types of bonds—hydrogen bonds, ionic bonds, van der Waal's interactions, covalent bonds and hydrophobic bonds.