Which of the following is not present in a nucleotide?

Guanine
Cytosine
Adenine
Tyrosine

Solution

Tyrosine is an α-amino acid, and not a purine.

Of the following statements about enzymes which ones are true?
(i)Enzymes lack in nucleophilic groups
(ii)Enzymes are highly specific both in binding chiral substrates and in catalysing their reactions
(iii)Enzymes catalyse chemical reactions by lowering the energy of activation
(iv)Pepsin is a proteolytic enzyme

(i) and (iv)
(i) and (iii)
(ii), (iii) and (iv)
(i)

The enzyme which hydrolyses triglycerides to fatty acids and glycerol is called

maltase
lipase
zymase
pepsin

Solution

Triglycerides are lipids, hence these are hydrolysed by lipases to glycerol and fatty acids.

Chargaff’s rule states that in an organism

Amounts of all bases are equal
Amount of adenine (A) is equal to that of thymine(T)and the amount of guanine (G) is equal to that of cytosine(C)
Amount of adenine (A) is equal to that of guanine(G)and the amount of thymine (T) is equal to that of cytosine(C)
Amount of adenine (A) is equal to that of cytosine (C)and the amount of thymine (T) is equal to that of guanine(G)

Solution

\(\frac{A}{T} = \frac{G}{C}\) = 1
Amount of A = T and that of G = C.

Which of the following is correct about H-bonding innucleotide?

A--- A and T--- T
G--- T and A --- C
A --- G and T --- C
A --- T and G --- C

Solution

Fructose on reduction gives a mixture of two alcohols which are related as

diastereomers
epimers
both (a) and (b)
anomers

Solution

Ketoses on reduction produce a new chiral carbon leading to the formation of two isomeric alcohols which are diastereomeric as well as C–2 epimers.

When adenine is attached to ribose sugar, it is called adenosine. To make a nucleotide from it, it would require