S1B4 - Bioenergetics

Question 1

What is a major, natural source of reactive oxygen species (ROS)?

Answer 1

ROS- mitochondria major source

• Formation of ROS is inevitable during normal oxidative metabolism

Question 2

What is the difference between anabolic and catabolic metabolic pathways?

Answer 2

Anabolic pathways (endergonic)

• Series of chemical reactions that synthesize biomolecules from smaller units
• Consume energy (ATP)

Catabolic pathways (exergonic)

• Series of chemical reactions that break down biomolecules into smaller units
• Release energy (ATP)

Question 3

What is the free energy equation?

Answer 3

Question 4

In what form does the energy from aerobic oxidation of glucose get conserved?

Answer 4

Oxidation of glucose releases a large quantity of energy – C6H12O6 + 6O2 → 6H2O – ∆G0’ = -2864 kJ/mol (-684 kcal/mol)

• In most cells this process occurs under aerobic conditions
  
  • Conserves energy as 38 molecules of ATP

Question 5

Why is the caloric value of lipids higher than carbohydrates and proteins?

Answer 5

Carbohydrates and proteins, caloric value of 12-16 kJ/g, while lipids has three times higher

• Due to average oxidation state of C atoms
• C atoms in carbohydrates are more oxidized (less reduced) than those in lipids

Question 6

What role does Mg²⁺ play in ATP hydrolysis?

Answer 6

Mg2+ draws electron density from the Os and makes the P more electronegative and easier to be attacked by H2O

Question 7

What do mutations, D32V / A63P, of Mycobacterium ATP synthase c-subunit of confer?

Answer 7

Mutations, D32V / A63P, of Mycobacterium ATP synthase c-subunit of confer resistance to the tuberculosis drugs.

Question 8

Bedaquiline is active against a number of drug resistant strains of Mycobacterium tuberculosis. Eradicates M. tuberculosis infection.

What is its mechanism of action?

Answer 8

Bedaquiline is active against a number of drug resistant strains of Mycobacterium tuberculosis. Eradicates M. tuberculosis infection

This drug blocks the synthesis of ATP.

Question 9

Ectopic ATP synthase is a drug target for what kind of cells?

Answer 9

Ectopic ATP synthase is a drug target for tumor cells?

Question 10

Why would MOSDOH students be interested in Streptococcus mutans?

Foods rich in what chemical should they recommend to their future patients that relates to S. mutans?

Answer 10

Streptococcus mutans is a primary microbial agent in the pathogenesis of dental cavities through biofilm formation and acid production.

Inhibition of ATP synthase of S. mutans inhibits biofilm formation and acid production.

• Dietary polyphenols inhibit ATP synthase activity