Life Sciences 2 - Week 6 - Energy Cycle Flashcards
1
Q
Describe the fundamental steps in Glycolysis?
A
- Glycolysis, occurring in the cytoplasm, involves the breakdown of glucose (6-carbons) into two molecules of pyruvate (3-carbons each).
- It is divided into two phases: Preparatory Phase (consumes 2 ATP) and Payoff Phase (produces 4 ATP and 2 NADH).
- Overall, glycolysis yields a net gain of 2 ATP molecules and 2 NADH molecules.
2
Q
What is the role of the Citric Acid Cycle (Krebs cycle)?
A
- Occurs in the mitochondrial matrix.
- Pyruvate from glycolysis is converted to Acetyl-CoA, which enters the cycle.
- Each cycle generates 1 ATP, 3 NADH, 1 FADH2, and 2 CO2 per Acetyl-CoA molecule.
3
Q
What are the fate of electrons produced by the Citric Acid Cycle?
A
- The electrons carried by NADH and FADH2 are transferred to the Electron Transport Chain (ETC), where they help drive ATP production.
4
Q
List the basic steps in the Electron Transport Chain (ETC):
A
- Occurs in the inner mitochondrial membrane.
- NADH and FADH2 pass electrons through a series of proteins, pumping protons into the intermembrane space, creating a proton gradient.
- ATP synthase uses this proton gradient to generate ATP via chemiosmosis.
5
Q
What are the different ways ATP is made?
A
- Substrate-level phosphorylation (e.g., during glycolysis and the Krebs cycle) directly produces ATP.
- Oxidative phosphorylation occurs in the ETC and is the primary way cells generate ATP, producing most of the ATP from one glucose molecule.
6
Q
Compare Anaerobic and Aerobic respiration.
A
Aerobic Respiration:
o Requires oxygen.
o Produces up to 36 ATP per glucose molecule.
o Complete breakdown of glucose through glycolysis, the Krebs cycle, and ETC.
Anaerobic Respiration:
o Occurs in the absence of oxygen.
o Relies on fermentation (e.g., lactic acid fermentation or alcohol fermentation) to regenerate NAD+.
o Produces only 2 ATP per glucose molecule, as it relies solely on glycolysis.
