Question

(10)

Which of the following steps in the catalytic cycle of the F₁ component of ATP synthase is the most energetically unfavorable?

Group of answer choices

Formation of ATP from ADP and P_i

Binding of P_i

Binding of ADP

Binding of ATP

Release of ATP

(11)

The reaction catalyzed by malate dehydrogenase (shown below) completes the citric acid cycle. The ΔG°’ for this reaction is equal to 29.7 kJ/mol.

L-malate + NAD+ ⇄ oxaloacetate + NADH + H⁺

Which of the following are factors that may contribute in favoring the formation of products?

Group of answer choices

High H⁺ concentration

Low concentration of NADH and high concentration of NAD⁺

High concentration of oxaloacetate

Low concentration of oxaloacetate

(b) and (d)

(12)

What is the most likely adaptation response of bacteria when the growth temperature is changed from near physiological (37°C) to cold (8°C)?

Group of answer choices

incorporation of saturated fatty acids in the membrane

incorporation of unsaturated fatty acids in the membrane

thermal compensation by upregulation of exergonic reactions

thermal compensation by downregulation of endergonic reactions

migration to warmer media

Answer 1

10) ATP synthase catalyzes the synthesis of ATP from ADP and inorganic phosphate (Pi) in the F1 component. However this is the most unfavorable reaction and normally goes in backward direction. To be favorable in forward direction, ATP synthase uses the electrochemical gradient of proton concentration across the mitochondrial membrane.

Therefore the most energetically unfavorable reaction for F1 component of ATP synthase is

a) Formation of ATP from ADP and Pi

11) The reaction catalyzed by malate dehydrogenase is altered by the concentration of L-malate, NAD+ and citrate. Citrate is known allosteric regulator of the enzyme malate dehydrogenase. In the presence of higher concentration of L-malate and NAD+, citrate enhances production of oxaloacetate. Also low concentration of oxaloacetate favors malate dehydrogenase activity.

Therefore, the factors that contribute the formation of product are

b) Low concentration of NADH and high concentration of NAD+

d) Low concentration of oxaloacetate

12) Microorganisms adapted themselves to low temperature through incorporation of unsaturated fatty acids in the membrane. This is to protect membrane from losing their biological function because membranes are only functional when they are in fluid state. Unsaturated fatty acids maintain membrane fluidity as these have low melting temperatures than the saturated and branched chain fatty acids. This reduces the temperature required for membrane to change from fluid to any other state as oppose to saturated fatty acids.

Therefore, The adaptation response of bacteria when growth temperature changes from near physiological (37°C) to cold (8°C)

b) Incorporation of unsaturated fatty acids in the membrane