7. Energy + Metabolism Flashcards
What are the main reasons cells need energy?
Metabolism, movement, growth, cell division, and action potentials.
What is ATP and why is it important?
ATP (adenosine triphosphate) is the universal energy currency of the cell.
What is cellular respiration?
The process of nutrient breakdown with accompanying ATP synthesis.
What does LEO the lion says GER mean?
Loss of Electrons = Oxidation; Gain of Electrons = Reduction
What are NAD⁺ and FAD?
Electron carriers derived from vitamins B3 and B2, respectively.
What do NAD⁺ and FAD do in redox reactions?
NAD⁺ picks up 2 e⁻ and 1 H⁺; FAD picks up 2 e⁻ and 2 H⁺.
What are the inputs and outputs of cellular respiration?
Inputs: glucose, O₂, ADP, Pi, NAD⁺, FAD
Outputs: CO₂, H₂O, ATP, NADH, FADH₂
What is the overall equation for cellular respiration?
C₆H₁₂O₆+ 6O₂ + 32 ADP + 32 Pi → 6CO₂ + 6H₂O + 32 ATP
What are the 4 stages of glucose catabolism
- Glycolysis (cytoplasm)
- Pyruvate oxidation (mitochondrial matrix)
- Krebs Cycle (mitochondrial matrix)
- Electron Transport Chain (inner mitochondrial membrane)
What happens in glycolysis?
Glucose (6C) is converted into 2 pyruvic acid (3C each).
What is the net energy gain from glycolysis?
2 ATP
What is the net energy gain from glycolysis?
2 ATP and 2 NADH.
What happens to pyruvate in the mitochondria?
It’s oxidized to acetyl-CoA, producing 1 CO₂ and 1 NADH per pyruvate.
What is the total yield from 2 pyruvates?
2 acetyl-CoA, 2 CO₂, and 2 NADH.
What combines with acetyl-CoA to start the Krebs cycle?
Oxaloacetate
What is produced per glucose molecule (2 acetyl-CoA)?
4 CO₂, 2 ATP, 6 NADH, 2 FADH₂.
For the electron transport chain, Where does NADH release its electrons?
Complex I of the ETC.
For the electron transport chain, Where does FADH₂ release its electrons?
Complex ll.
What is the final electron acceptor in the ETC?
Oxygen, forming water
How is ATP produced in ETC?
Through chemiosmosis: H⁺ gradient powers ATP synthase.
How much ATP yield per NADH in ETC
~2.5 ATP.
How much ATP yield per FADH2 in ETC
~1.5 ATP.
How much ATP is theoretically produced from one glucose molecule?
32 ATP.
Why might actual ATP yield be lower?
Loss during NADH transport, inefficiencies, and immediate energy use.
