Respiration Flashcards
What are the four stages of Aerobic Respiration?
- glycolysis
- Link reaction
- Krebs Cycle
- Respiratory Chain/ETC/Oxidative Phosphorylation/Chemiosmosis
Where does Glycolysis occur?
Cytoplasm
Where does the link reaction and Krebs cycle occur?
Mitochondrial Matrix
Where does oxidative phosphorylation occur?
The electron transport chain on the inner membrane and in the Intermembrane space
List whether the stages of respiration are aerobic or anaerobic
Anaerobic - Glycolysis
Aerobic- Link reaction, Krebs and ETC
Explain glycolysis
Glucose is phosphorylated by 2 ATP molecules to turn it into two Triose phosphate which then changes into pyruvate molecules, releasing 4 ATP molecules and hydrogen atoms which are used to reduce NAD into NADH
Explain the link reaction
In the presence of oxygen, pyruvate enters the matrix and is oxidised into an Acetyl compound with combines with Coenzyme A to make Acetyl CoA. In turning into the Acetyl compound, the pyruvate dehydrogenates and decarboxylates, meaning it releases hydrogen atoms which create more NADH and CO2.
Explain the Krebs Cylce
- 2 Carbon Acetyl CoA is reduced by ***4 Carbon Oxaloacetate to form 6 Carbon Citrate
- Citrate is oxidised to form oxaloacetate, CO2, H AND ATP
- H is used to reduce NAD and FAD into NADH and FADH2, which is then sent to the ETC.
Explain Oxidative phosphorylation
NADH and FADH2 bind to complexes 1 and 2 respectively and release their hydrogen atoms as hydrogen ions and electrons and return to the Krebs cycle.
The electrons are passed along the protein complexes, going down in energy levels each time. The energy released is used to pump the hydrogen ions into the intermembrane space by active transport to maintain a proton gradient across the membrane.
At the final electron complex, the electrons are combined with protons and oxygen to form water. Protons in the inter membrane space diffuse down their concentration gradient through the proton channel leading to the ATP SYNTHASE molecule, which creates one ATP from ADP and Pi for every 4 protons
What are the key features of mitochondria?
- Double Membrane
- Intermembrane space
- Cristae
- Mitochondrial Matrix
- ATP Synthase
- Ribosomes
- DNA
Why does aerobic respiration stop if there is no oxygen?
If there is no oxygen there is no final electron acceptor in the ETC so no electrons can leave the ETC leading to a buildup of NADH that can’t unload its hydrogen. Without NAD glycolysis and Krebs cycle don’t work.
How does Anaerobic Respiration work in animals?
Pyruvate is reduced to Lactate, using the H from the NADH, supplying more NAD to allow Glycolysis to continue. This is a reversible reaction
How does Anaerobic Respiration work in plants and fungi?
Pyruvate is reduced to Ethanol and Carbon Dioxide using NADH supplying NAD for Glycolysis to continue. This is an irreversible reaction.
How many molecules of ATP are made in anaerobic respiration?
2
ATP is useful in many biological processes. Explain why. (4 marks)
Releases energy in small amounts
Broken down in a one step
Can be reformed
It is and immediate energy compound so makes energy rapidly available
Adds phosphate
Makes phosphorylated substances more reactive
