Topic 5 - Respiration Flashcards
What is step one of anaerobic and aerobic respiration?
Glycolysis
Where in the cell does glycolysis occur?
In the cytoplasm
What are the 3 key steps in glycolysis?
1) Glucose is phosphorylated to glucose phosphate, using two molecules of ATP.
2) Triose phosphate (TP) is produced.
3) Oxidation of TP to produce pyruvate with a net gain of ATP and reduced NAD (NADH)
What happens to the net gain of ATP and reduced NAD?
Pyruvate and NADH are actively transported from the cytoplasm into the mitochondrial matrix.
What are the products of glycolysis?
2x pyruvate
Net gain of 2x ATP
2x NADH
What are the 3 main steps of the link reaction?
- The pyruvate made in glycolysis is oxidised to acetate.
- NAD picks up the hydrogen and becomes reduced NAD (NADH)
- Acetate then combines with coenzyme A to produce acetyl coenzyme A
What are the products of the link reaction for every glucose molecule?
2x Acetyl CoA
2x CO2
2x NADH
What are the two main steps in the Kreb’s cycle?
- Acetyl CoA reacts with a 4C molecule releasing CoA and producing 6C molecule that enters the Kreb cycle.
- In a series of redox reactions, the Krebs cycle generates reduced coenzymes and ATP by substrate level phosphorylation and CO2 is lost.
What are the products of the krebs cycle per cycle?
3x NADH
1x FADH
1x ATP
2x CO2
What are the products of the krebs cycle per glucose molecule?
6x NADH
2x FADH
2x ATP
4x CO2
What does oxydative phosphorylation involve?
Involves:
- The electron transfer chain
- Movement of protons across the inner mitochondrial membrane
- Catalysed by ATP synthase
Explain the process of oxidative phosphorylation.
- NADH and FADH coenzymes deliver their electrons to the first protein in the ETC.
- Electrons are passed along the ETC in a series of redox reactions.
- As the electrons move along, energy is released which provides energy to pump H+ into the intermembrane space.
- This causes an electrochemical gradient to be established.
- H+ can diffuse back into the centre of the mitochondria through ATP synthase enzyme. The ATP synthase turns as the H+ moves through, making ATP from ADP and Pi as it does so.
- Oxygen in the matrix picks up the electrons at the end of the ETC as well as protons to form H2O. (oxygen is the final electron acceptor)
Where in the cell does glycolysis occur?
Cytoplasm
Where in the cell does the link reaction occur?
In the mitochondrial matrix.
Where in the cell does the krebs cycle occur?
In the mitochondrial matrix
Where in the cell does oxidative phosphorylation occur?
In the mitochondrial cristae.
Where does anaerobic respiration occur?
In the cytoplasm only.
What is pyruvate reduced to in anaerobic respiration?
Pyruvate is reduced to form ethanol and CO2 in plants and lactate in animals.
This oxidises NAD so that it can be reused in glycolysis and ensure more ATP is continued to be produced.
What are the four stages of aerobic respiration?
1) Glycolysis.
2) Link reaction.
3) Krebs Cycle.
4) Oxidative phosphorylation.
Where does glycolysis occur?
Occurs in the cytoplasm
What is anaerobic respiration?
Respiration in the absence of oxygen.
Where does anaerobic respiration take place?
Only occurs in the cytoplasm.
What happens in anaerobic respiration?
Pyruvate that is produced in glycolysis is reduced to form ethanol and carbon dioxide (in plants) or lactate (in animals.
What is the product of anaerobic respiration in plants?
Ethanol and carbon dioxide
What is the product of anaerobic respiration in animals?
Lactate
Describe the process of glycolysis [4]
1) Phosphorylation of glucose using ATP.
2) Oxidation of triose phosphate to pyruvate.
3) Net gain of ATP.
4) NAD reduced
Why does inhibition of the Krebs cycle decrease the uptake of oxygen in a respiring cell? [2]
1) Less reduced NAD and fewer electrons removed and passed to ETC
2) Oxygen is the final electron acceptor
Explain why converting pyruvate to lactate allows the continued poduction of ATP by anaerobic respiration [2]
1) Regenerates NAD
2) So glycolysis can continue.
What is the advantage of the Bohr effect during intense exercise [2]
1) Increased dissociation of oxygen
2) For aerobic respiration at the tissues/muscles/cells.
Where in the cell is glucose converted into pyruvate? [1]
Cytoplasm
How does the conversion of pyruvate to ethanol and CO2 allow the conversion of glucose to pyruvate to continue? [2]
1) Regenerates NAD
2) NAD reduced in glycolysis
Describe how acetylcoenzyme A is formed in the link reaction [2]
1) Oxidation of/ hydrogen removed from pyruvate and carbon dioxide released
2) Addition of coenzyme A
Why does converting pyruvate to lactate allow the continued production of ATP during anaerobic respiration? [2]
1) Regenerates /produces NAD/oxidises reduced NAD
2) NAD used in glycolysis.
