Alternative Aerobic Pathways

Question 1

Evolutionary Significance of Glycolysis

Answer 1

• Ancient prokaryotes used glycolysis long before there was oxygen in the atmosphere
• Early prokaryotes likely used only glycolysis to generate ATP
• Glycolysis is a very ancient process

Question 2

What is the function of catabolic pathways?

Answer 2

Funnel electrons from many kinds of organic molecules into cellular respiration

Question 3

How are proteins digested?

Answer 3

• Must be digested to amino acids via deamination
• Amino groups can feed glycolysis, acetyl-Co-A or the Kreb’s Cycle

Question 4

How are fats digested?

Answer 4

• Digested to glycerol which is used in glycolysis
• Digested to fatty acids which is used in generating acetyl-Co-A

Question 5

How are fatty acids broken down?

Answer 5

• By beta oxidation
• They yield acetyl-Co-A

Question 6

Oxidation of fats vs carbs

Answer 6

An oxidized gram of fat produces more than twice as much ATP as an oxidized gram of carbohydrate

Question 7

What happens when ATP over accumulates?

Answer 7

• Process called: Feedback Inhibition
• ATP becomes an allosteric inhibitor, this stops glycolysis by binding to phosphofructokinase

Question 8

What happens when ATP concentration drops?

Answer 8

Respiration speeds up

Question 9

Gluconeogenesis

Answer 9

• Process where glucose is formed using reverse processes to make glucose from scratch

Question 10

Note about ammonia

Answer 10

• Highly toxic
• Liver attaches CO2 groups to make “urea” which is urinated out of the body (in mammals)

Question 11

B-Oxidation

Answer 11

• Breaks down fatty acids into C’s, H’s and O’s to make acetyl
• It alters carbon groups

Question 12

Deamination

Answer 12

Removal of an amino group from a molecule