How many tripeptides can be prepared by linking the amino acids glycine, alanine and phenyl alanine?

• One

• Three

• Six

• Twelve

A codon has a sequence of A, and specifies a particular B that is to be incorporated into a C. What are A, B and C?

• A - 3 bases; B - amino acid; C - carbohydrate

• A - 3 acids; B - carbohydrate; C - protein

• A - 3 bases; B - protein; C - amino acid

• A - 3 bases; B - amino acid; C - protein

The AT/GC ratio in human beings is (where A = adenine, T = thymine, G = Guanine, C = cytosine).

• 1

• 1.52

• 9.3

• 2

94.

Which one of the following statements is not correct?

• Except glycine all other naturally occurring α-amino acids are optically active.

• α-amino acids have maximum solubility at their isoelectric point.

• A tripeptide has two peptide bonds.

• α-amino acids exist as Zwitter ions.

Which one of the following is true for an exothermic reaction A $\rightleftharpoons$ B, if E_f and E_b are the activation energies of forward and backward reactions respectively?

• E_f > E_b

• E_f = E_b

• E_f = -E_b

• E_f < E_b

The site of action of insulin is

• mitochondria

• nucleus

• plasma membrane

• DNA

The number of hydrogen bonds between guanine and cytosine and between adenine and thymine in DNA is

• 1, 2

• 3, 2

• 3, 1

• 2, 1

The amino acid containing indole part is

• tryptophan

• tyrosine

• proline

• methionine

What are the substances which mimic the natural chemical messengers?

• Antibiotics

• Antagonists

• Agonists

• Receptors

Lactose is disaccharide of

• α- D - glucose and α- D - fructose

• β- D- glucose and β- D-galatose

• α- D - glucose and  β- D-ribose

• α- D - glucose and  β- D-galactose