Lecture 15: Respiration Intro Glycolysis

Question 1

Know the definition and objective of cellular respiration

Answer 1

• Cellular Respiration: The process in which sugars (glucose) are converted into usable energy (ATP).

Question 2

Know and describe the four stages of cellular respiration, including the
order in which they occur relative to one another

Answer 2

I. Glycolysis (cytoplasm):
Glucose is
partially broken down and energy is
released; lipids and proteins may also
be broken down by different pathways

II. Acetyl
-CoA synthesis
(mitochondria): Pyruvate, produced from the breakdown of glucose in
glycolysis, is converted to Acetyl-CoA and CO2

III. Citric Acid Cycle (mitochondria):
Acetyl-CoA is broken down releasing CO2, energy, and electron carriers

IV. Oxidative phosphorylation
(mitochondria): electron carriers from stages 1−3 release their high-energy
electrons to the electron-transport chain to produce ATP

Question 3

Describe oxidation-reduction reactions (including oxidizing agent, reducing
agent, oxidized product, reduced product)

Answer 3

Oxidation: loss of electrons/decrease in electron density

Reduction: gain of electrons/increase in electron density

Question 4

Describe the breakdown of glucose relative to an oxidation-reduction
reaction

Answer 4

ie) Breakdown of glucose: glucose is oxidized to carbon dioxide and
oxygen is reduced to water

Question 5

Describe the process of carbohydrate catabolism

Answer 5

?

Question 6

Define, describe, and compare the electron carriers NAD+ and FAD

Answer 6

Oxidized forms:
NAD+, FAD
- oxidized
electron carriers accept
electrons and become reduced.
Reduced forms:
NADH, FADH2
- Reduced electron carriers
have a high potential
energy that is used to
synthesize ATP

Question 7

Describe the process of substrate-level phosphorylation

Answer 7

- A phosphorylated organic
molecule transfers a
phosphate group to ADP to
produce ATP.
- Only produces a small amount of ATP.

Question 8

Define glycolysis (and the impact of oxygen on this stage of respiration)

Answer 8

• Starting molecule of glycolysis is glucose and its end product is pyruvate (a 3C sugar).
• 2 pyruvates are produced for each glucose that enters.
• glycolysis is anaerobic.

Question 9

Know the 3 phases of glycolysis and the amounts of ATP, NADH, and
pyruvate produced per glucose molecule by the end of glycolysis

Answer 9

Phase 1:
Investment
Phase 2:
Cleavage
Phase 3:
Pay off

• For each molecule of glucose that enters glycolysis we get:
• 2 ATP
• 2 NADH
• 2 pyruvate

Question 10

For the 3 phases of glycolysis, you will be expected to know the reactants and products for those reactions that (1) require ATP to proceed (2) produce ATP and (3) reduce NAD+ to NADH

Answer 10

Step 1:
glucose converted to glucose 6-phosphate, ATP to ADP.

Step 3:
fructose 6 phosphate converted to fructose 1,6 bis-phosphate. ATP to ADP.

Step 6:
glyceraldehyde 3-phosphate converted to 1,3 bisphosphoglycerate. 2NAD+ to 2NADH.

Step 7:
1,3 bisphosphoglycerate converted to 3-phosphoglycerate. 2ADP to 2ATP.

Step 10:
phosphoenyl pyruvate converted to pyruvate. 2 ADP to 2ATP.