Biochemistry II: Unit II - Energy Changes and Electron Transfer in Metabolism

What does the Law of Conservation of Energy state in terms of energy balance?

Energy intake equals internal heat produced + work + storage. (correct)
Energy intake equals only internal heat produced.
Energy intake equals external work done.
Energy intake equals mechanical work of motion.

How are catabolism and anabolism related in terms of metabolism?

Catabolism requires energy while anabolism releases energy.
Catabolism is reductive and anabolism is oxidative.
Catabolism releases energy while anabolism requires energy. (correct)
Catabolism and anabolism are the same pathways in opposite directions.

Which category of biochemical reactions involves C-C bond making or breaking?

C-C bond making or breaking (correct)
Free-radical reactions
Group transfers
Internal rearrangements, isomerizations, and eliminations

In what way do living things differ from non-living systems in terms of thermodynamics?

Living things are unique thermodynamic systems. (B) Signup and view all the answers

Why aren't catabolism and anabolism simply considered as reverse processes of each other?

They operate in different pathways. (B) Signup and view all the answers

What role does stored chemical energy play in driving endergonic reactions?

Releasing energy to drive endergonic reactions. (D) Signup and view all the answers

Which coenzymes are tightly bound to the enzymes they serve as prosthetic groups?

FMN and FAD (A) Signup and view all the answers

For what purpose is NADPH primarily used?

Reductive biosyntheses (A) Signup and view all the answers

What does dietary deficiency of niacin cause?

Pellagra (B) Signup and view all the answers

Which coenzymes undergo reversible oxidation and reduction in many electron-transfer reactions of metabolism?

NAD and NADP (C) Signup and view all the answers

What happens to the concentration of NAD+ + NADH during the recycling of coenzyme?

No change (C) Signup and view all the answers

Which coenzyme consists of the structure above the dashed line on the FAD (oxidized form)?

FMN (A) Signup and view all the answers

Which of the following statements about ATP hydrolysis is correct?

A thermodynamically unfavorable reaction can be made favorable by coupling it to the hydrolysis of a sufficient number of ATP molecules. (C) Signup and view all the answers

Which of the following statements about nucleophilic reactions of ATP is incorrect?

Only the β- and γ-phosphorus atoms of ATP can serve as electrophilic targets for nucleophilic attack. (A) Signup and view all the answers

Which of the following statements about the flow of electrons in biological systems is incorrect?

The complete oxidation of glucose has a standard free energy change ($\Delta G^\circ$) of +2,840 kJ/mol. (C) Signup and view all the answers

Which of the following statements about coenzymes in biological redox reactions is correct?

Coenzymes such as NAD+ and FAD+ are specialized for carrying electrons released from redox reactions. (C) Signup and view all the answers

Which of the following statements about fats as fuel sources is correct?

Fats are a more efficient fuel source than carbohydrates like glucose because the carbon in fats is more reduced. (C) Signup and view all the answers

Which of the following statements about the firefly bioluminescence cycle is correct?

The firefly bioluminescence cycle is an example of a nucleophilic reaction involving ATP. (B) Signup and view all the answers

Which of the following biochemical reactions involves the breaking or making of carbon-carbon bonds?

Cholesterol biosynthesis (C) Signup and view all the answers

Which of the following statements about group-transfer reactions is incorrect?

Group-transfer reactions do not involve the transfer of inorganic orthophosphate (Pi) or inorganic pyrophosphate (PPi). (D) Signup and view all the answers

Which of the following statements about ATP is incorrect?

ATP provides energy solely through simple hydrolysis, not through group transfers. (D) Signup and view all the answers