Chapter 4 - Metabolism and Energy

Question 1

Obligate Aerobe

Answer 1

An obligate aerobe is an organism that cannot live without oxygen. Examples: most eukaryotes including plants
and animals.

Question 2

4 Stages Aerobic Cellular Respiration

Answer 2

1. Glycolysis
2. Pyruvate Oxidation
3. Citric Acid Cycle (aka Krebs Cycle)
4. Electron Transport Chain and Oxidative Phosphorylation

Question 3

Substrate Level Phosphorylation

Answer 3

is the formation of ATP by the direct transfer of a phosphate group from a
substrate to ADP.

Question 4

Oxidative Phosphorylation

Answer 4

is a process that forms ATP using energy transferred indirectly from a series of redox
reactions.

Question 5

Glycolysis (cytosol)

Answer 5

Enzymes break down one molecule of glucose into two molecules
of pyruvate. Some high-energy ATP (via substrate-level
phosphorylation) and NADH is synthesized.

Question 6

Pyruvate Oxidation (mitochondria matrix)

Answer 6

Each of the two molecules of pyruvate produced in glycolysis is
transported to the mitochondria is oxidized, resulting in the
production of CO2 (a waste molecule), NADH, and an acetyl group
that is initially attached to coenzyme A (acetyl-CoA).

Question 7

Citric Acid Cycle (mitochondria matrix)

Answer 7

Acetyl-CoA molecules from pyruvate oxidation enter a metabolic
cycle, where the acetyl group is completely oxidized to CO2. In the
process, ATP (via substrate-level phosphorylation) and the electron
carriers NADH and FADH2 are synthesized.

Question 8

Electron Transport & Oxidative Phosphorylation (mitochondria on inner membrane)

Answer 8

The NADH and FADH2 (synthesized during glycolysis, pyruvate
oxidation and the citric acid cycle) are oxidized. Their high-energy
electrons and hydrogens are passed from oxidizing agent to the
next until they are transferred to O2, producing water. The free
energy released during electron transport is indirectly used to
synthesize a large amount of ATP by oxidative phosphorylation.

Question 9

Anaerobic Respiration

Answer 9

Anaerobic respiration is a process that uses a final inorganic oxidizing agent other than oxygen to produce energy.

Question 10

Fermentation

Answer 10

Fermentation is a process that uses an organic compound as the final oxidizing agent to produce energy.

Question 11

Facultative Anaerobes

Answer 11

an organism that can live with or without oxygen.

Question 12

Alcohol Fermentation

Answer 12

• aka ethanol fermentation
• occurs in a variety of organisms including certain bacteria and yeast
  
  • Saccharomyces
    cerevisiae used in bread
    making (ethanol
    evaporates, CO2
    produced makes the
    bread rise)
  • wine/beer-making -
    involves a mixture of
    wild and cultivated
    yeasts