Cellular Respiration Flashcards
Name the four steps of Cellular Respiration in Aerobic restoration
- Glycolysis
- Pyruvate Processing
- Kreb’s Cycle
- ETP and OP
Functions that require energy
Growth, reproduction, sensing/responding to the environment, maintaining homeostasis
What does a redox reaction mean
Reduction: Electron is gained
Oxidation: Electron is lost
Anaerobic Respiration Characteristics
Doesn’t need O2
Faster
More waste
less efficient
Aerobic Respiration Characteristics
More efficient
requires O2
Fully oxidizes glucose
Less waste
Where does glycolysis happen
The Cytoplasm/Cytosol of the cell
Molecules required for Glycolysis
Glucose, 2 ATP, 2 NAD+, 4 ADP + 4Pi
molecules produced by glycolysis
2 Pyruvate, 2 Net ATP, 2 NADH, 2 H2O
What regulates Glycolysis
High levels of ATP, because excess ATP binds to phosphofructokinase regulatory site, inhibiting the reaction
Investment Stage of Glycolysis
Uses 2 ATP to phosphorylate glucose and make it unstable.
Payoff phase of Glycolysis
Generates 4 ATP (net gain of 2 ATP) and 2 NADH through substrate-level phosphorylation.
Where does pyruvate processing happen
Mitochondrial Matrix
Molecules required by pyruvate processing
2 Pyruvate (from glycolysis)
2 NAD⁺
2 Coenzyme A (CoA)
Molecules produced by pyruvate processing
2 Acetyl-CoA (enters the citric acid cycle)
2 NADH (electron carriers)
2 CO₂ (waste product, exhaled)
How is pyruvate processing regulated
Feedback Inhibition
What happens during pyruvate processing
Pyruvate enters mitochondria
CO₂ is removed
NAD⁺ is reduced to NADH
CoA attaches to form Acetyl-CoA
Location of Kreb’s Cycle
Mitochondrial matrix
Molecules required for Kreb’s Cycle
2 Acetyl-CoA (from pyruvate processing)
6 NAD⁺
2 FAD
2 ADP + 2 Pi
2 Oxaloacetate (recycled at the end)
Molecules produced by Kreb’s Cycle
4 CO₂ (waste, exhaled)
6 NADH (electron carriers)
2 FADH₂ (electron carriers)
2 ATP (or GTP) (direct energy production)
Oxaloacetate (regenerated to restart the cycle)
How is Kreb’s cycle regulated
Regulated by feedback inhibition
Why is Kreb’s Cycle a cycle
The final molecule (oxaloacetate) is regenerated and used again to start the next round.
Each time Acetyl-CoA enters, it combines with oxaloacetate to form citrate, which eventually breaks down back into oxaloacetate.
Why Does Glucose Oxidation Happen Here?
This is where most high-energy electrons are stripped from carbon-containing molecules.
The 6-carbon glucose (originally from glycolysis) is fully broken down into CO₂ and electrons (carried by NADH and FADH₂).
These electrons will be used in the electron transport chain to make ATP.
steps of Kreb’s cycle
1)Combine → Acetyl-CoA (2C) + Oxaloacetate (4C) → Citrate (6C)
2) Cut & Capture → Carbon is removed as CO₂, and energy is captured in NADH.
3️⃣ Energy Extraction → ATP (or GTP) is made, and FADH₂ is produced.
4️⃣ Reset → Oxaloacetate is regenerated to start again.
Where ETC happens
Inner mitochondrial membrane
What Happens to the Energy in the Electrons during ETC?
Electrons from NADH & FADH₂ are passed through protein complexes in the ETC, losing energy at each step.
This energy is used to pump protons (H⁺) into the intermembrane space, creating a proton gradient.
Where Do the Electrons End Up during ETC?
At the final complex, electrons combine with O₂ (oxygen) and H⁺ to form H₂O (water).
Oxygen is the final electron acceptor, preventing backup in the chain.
What Is the Released Energy Used For?
It drives H⁺ (protons) out of the matrix into the intermembrane space, creating a proton gradient.
Why Is the Proton Gradient Important?
It creates potential energy (like a battery).
Protons rush back into the matrix through ATP synthase, powering ATP production in oxidative phosphorylation.
Why Is Oxygen Required for ETC?
Oxygen is the most electronegative molecule in the process, pulling electrons through the chain.
Without oxygen, electrons back up, stopping the ETC and ATP production, leading to cell death.
two types of fermentation
Alcohol and Lactic
What happens during lactic fermentation
Pyruvate (from glycolysis) is reduced to lactate (lactic acid).
NADH donates electrons to pyruvate → Converts NADH back to NAD⁺.
NAD⁺ is recycled so glycolysis can keep making ATP.
