Lecture 14: Metabolism

Question 1

Match the following to their correct position on the column below:
- Aerobic heterotrophs
- Facultative anaerobes
- Green sulfur bacteria
- Sulfur bacteria
- Purple sulfur bacteria
- Sulfate reducers

Answer 1

Question 2

What is the difference between catabolic and anabolic reactions?

Answer 2

1. Catabolic
   - Break down complex molecules and releases energy
2. Anabolic
   - Uses energy to build complex molecules from simple compounds

Question 3

Assimilation is _____. Dissimilation is _____.
(Catabolic vs. anabolic)

Answer 3

Assimilation is anabolic. Dissimilation is catabolic.

Question 4

What are equilibrium vs. exergonic vs. endergonic reactions?

Answer 4

• Equilibrium reactions are stable
• Exergonic reactions release energy
• Endergonic reactions require energy

Question 5

What is Gibbs free energy change?

Answer 5

Measure of energy available to do work

Question 6

How would you characterize this reaction?
- Dehydration or hydrolysis
- Anabolic or catabolic
- Exergonic or endergonic

Answer 6

• Dehydration
• Anabolic
• Endergonic

Question 7

Is this an exergonic or endergonic reaction?

Answer 7

Exergonic

Question 8

Is this an exergonic or endergonic reaction?

Answer 8

Endergonic

Question 9

What is the difference between hydrolysis and dehydration?

Answer 9

Dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy

Question 10

What are the effects of temperature on enzyme activity?

Answer 10

• At temperatures BELOW the optimum temperature: enzyme works, but works better the closer you get to optimum temperature
• At temperature ABOVE the optimum temperature: enzyme becomes denatures –> sharp drop in enzyme activity

Question 11

What are the effects of pH on enzyme activity?

Answer 11

• Enzyme has the most activity at the optimum pH
• Enzyme activity gradually decreases the farther you move away from the optimum pH

Question 12

What are the effects of inhibitors on enzyme activity?

Answer 12

Slow down the reaction rate, or in some cases, even stop the catalysis

Question 13

Explain oxidation vs. reduction.

Answer 13

Question 14

Explain the electron potential tower.

Answer 14

• Electrons donated by couples at the top of the tower can be “caught” by acceptors at various levels
• The farther they fall, the greater the difference in redox potential –> THE MORE ENERGY RELEASED!

Question 15

What is the function of bacteriochlorophyll?

Answer 15

Allows bacteria to photosynthesize without producing oxygen