Respiration Flashcards
What is respiration?
Respiration is a biochemical process where cells produce energy (ATP) by breaking down glucose and other organic molecules.
What are the two types of respiration?
Anaerobic and aerobic.
What are the main four stages of aerobic respiration?
1) Glycolysis
2) Link Reaction
3) Krebs Cycle
4) Oxidative phosphorylation
What happens during glycolysis?
Glucose is phosphorylated into glucose phosphate using 2ATP. Triose phosphate is produced and oxidised into pyruvate. Final products are 2 pyruvate , a net gain of 2ATP , and 2NADH.
Where does glycolysis occur?
In the cytoplasm.
What happens during the link reaction?
- Pyruvate is oxidised into acetate, producing NADH. The acetate then combines with coenzyme A to produce acetyl-coenzyme A. Final products are 2AcetylCoA , 2CO2 released , and 2 NADH (the link reaction happens twice for every glucose molecule).
Where does the link reaction occur?
In the mitochondrial matrix.
What happens during the Krebs Cycle?
- AcetylCoA reacts with a 4C molecule, releasing coenzyme A and producing a 6C molecule. In a series of oxidation-reduction reactions, the Krebs Cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and CO2 is lost. Final products (per glucose molecule) are 6NADH, 2ATP, 2FADH, and 4CO2.
Where does the Krebs Cycle occur?
In the mitochondrial matrix.
What happens during oxidative phosphorylation?
- Electrons from NADH and FADH are passed down along the ETC, creating a flow of electrons. This flow pumps H+ across the mitochondrial membrane, creating a proton gradient. The protons move back across the membrane via ATP synthase, producing ATP. Oxygen acts as the final electron acceptor, combining with protons and electrons to form water.
Where does oxidative phosphorylation occur?
In the inner mitochondrial membrane.
What is the final electron acceptor?
Oxygen, which combines with protons and electrons to form water.
What happens to pyruvate in anaerobic respiration in animals?
Pyruvate is reduced to lactate (lactic acid) to regenerate NAD⁺ for glycolysis.
What happens to pyruvate in anaerobic respiration in plants and yeast?
Pyruvate is converted to ethanol and CO₂, regenerating NAD⁺ for glycolysis.
Why does anaerobic respiration produce less ATP than aerobic respiration?
Anaerobic respiration only uses glycolysis, which produces a net gain of 2 ATP per glucose molecule, whereas aerobic respiration produces up to 38 ATP.
