A person has 400 million alveoli per lung with an average radius of 0.1 mm for each alveolus. Considering the alveoli are spherical in shape, the total respiratory surface of that person is closest to 

(A)  500 mm² (B)  200 mm² (C)  100 mm² (D)  1000 mm²

Glucagon increases the blood glucose concentration by 

(A)  promoting glycogenolysis. 

(B)  increasing the concentration of fructose 2,–6-bisphosphate.

(C)  increasing the concentration of pyruvate kinase.

(D)  inhibiting gluconeogenesis. 

What is the genetic material of Ebola virus ?

(A)  Single-stranded DNA

(B)  Double-stranded RNA

(C)  Single-stranded RNA

(D)  Double-stranded DNA 

Restriction endonucleases are enzymes that are used by biotechnologists to

(a) cut DNA at specific base sequences

(b) join fragments of DNA

(c) digest DNA from the 3′ end

(d) digest DNA from the 5′ end

A person was saved from poisonous snake bite by anti-venom injection. Which of the following immunities explains this form of protection?

(a) Naturally acquired active immunity

(b) Artificially acquired active immunity

(c) Naturally acquired passive immunity

(d) Artificially acquired passive immunity

A sequence of amino acids may end in either an amino group (—NH₂) or a carboxyl group (—COOH). What is the theoretical number of chemically different dipeptides that may be assembled from 20 different amino acids?

(a) 40

(b) 80

(c) 160

(d) 400

A bird sitting on a single high tension wire does not get electrocuted because

(A)  the circuit is not complete.

(B)  the bird feet has an insulating covering.

(C)  capacitance of the bird is too small and the line frequency is too small.

(D)  resistance of the bird is too high  

Upon mixing equal volumes of aqueous solutions of 0.1 M HCl and 0.2 M H₂SO₄, the concentration of H⁺ in the resulting solution is

(a) 0.30 mol/L

(b) 0.25 mol/L

(c) 0.15 mol/L

(d) 0.10 mol/L

Kreb’s cycle was discovered by Krebs in pigeon muscles in 1940. Which step is called gateway step/link reaction/transition reaction in respiration? 

(a) Glycolysis 

(b) Formation of acetyl Co-A 

(c) Citric acid formation 

(d) ETS terminal oxidation

Which of the following graphs best describes the oxygen dissociation curve where pO₂ is the partial pressure of oxygen ?