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

• 1

• 1.52

• 9.3

• 2

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

375.

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

Observe the following statements.

I. Sucrose has glycosidic linkage.

II. Cellulose is present in both plants and animals.

III. Lactose contains D-galactose and D-glucose units.

Which of the following statements are correct?

• (I), (II) and (III)

• (I) and (II)

• (II) and (III)

• (I) and (III)

Identify the statement which is not correct from the following.

(i)Carbohydrates are stored as glycogen in animals.

(ii) In glycylalanine, CO of peptide bond belongs to alanine.

(iii) Base - sugar- phosphate unit is known as nucleoside.

(iv) Obesity is due to hypothyroidism.

The correct answer is:

• i, iv

• ii, iii, iv

• i, iii, iv

• ii, iii