5.8 Respiration Flashcards
Why do organisms need to respire?
- Active transport
- Anabolic reactions
- Movement
- Mitosis
- Exocytosis
- Endocytosis
(AAMMEE)
Describe the structure of the mitochondria
- Mitochondrial DNA
- Matrix
- Inner mitochondrial membrane (folded) including the Cristae
- Outer mitochondrial membrane
- Ribosomes
Describe the process of respiration
respiration is the process which allows cells to produce ATP from glucose or other complex organic molecules.
What are the four stages of aerobic respiration?
Stage 1 - glycolysis
Stage 2 - the link reaction
Stage 3 - the Krebs cycle
Stage 4 - oxidative phosphorylation
where does glycolysis occur?
In the cytoplasm of a respiring cell
where does the link reaction occur?
In the mitochondrial matrix
where does the Krebs cycle occur?
In the mitochondrial matrix
Where does oxidative phosphorylation occur?
in the Cristae of the inner mitochondrial membrane
explain the process of glycolysis.
- Glucose phosphorylation from Glucose to Hexose Bisphosphate by two ATP molecules
- Splitting of hexose bisphosphate into 2 triose phosphate
- Triose phosphates are oxidised by NAD to form NADred and two ATP molecules per triose phosphate are made. Substrate level phosphorylation.
What are the products of glycolysis?
:
- 2 net ATP
- 2 x pyruvate
- 2 x NADred
explain the process of the link reaction
- Pyruvate is decarboxyalted (- CO2) and reduced by NAD to make acetyl and NADred
- Acetyl combines with coenzyme A (CoA) to form acetyl-CoA.
What are the products of link reaction?
:
- 2 x CO2
- 2 x NADred
- 2 x acetylCoA
Explain the process of the Krebs cycle
- AcetylCoA releases acetyl (2C) which combines with oxaloacetate (4C) to form citrate (6C)
- Citrate undergoes, decarboxylation and reduction by NAD. This forms at 5C compound
- The 5C compound undergoes decarboxylation and reduction too to form a 4C compound
- The 4C compound undergoes substrate level phosphorylation to produce ATP from ADP + Pi
- The 4C compound then undergoes reduction by FAD and NAD to reform oxaloacetate.
What are the products of the Krebs cycle?
For every 2 turns
- 2 x ATP
- 6 x NADred
- 2 x FADred
- 4 x CO2
what is the electron transport chain?
(in respiration)
it’s a series of carrier proteins embedded in the membrane of the Cristae. They produce ATP by oxidative phosphorylation via chemiosmosis during aerobic respiration.
what happens in the electron transport chain?
electrons are released from NADred and FADred they passed through the chain, releasing energy, which allows the H+ ions through. Oxygen access the final electron acceptor in the chain.
State the role of oxygen and aerobic respiration and what byproduct is produced?
It’s the final electron acceptor in the electron transport chain it produces water as a byproduct
What is the process of anaerobic respiration in animals?
- Glycolysis ( glucose -> pyruvate)
- Lactate fermentation (pyruvate -> lactic acid)
It’s reoxidises NADred
What is the process of anaerobic respiration in yeast and plants?
- glycolysis ( glucose ~> pyruvate)
- Alcoholic fermentation ( pyruvate ~> ethanal ~> ethanol)
- pyruvate to ethanal = - CO2
- ethanal to ethanol = NADred ~> NAD
Why does lactate / ethanal fermentation occur
- To produce re oxidised NAD from NADred so that glycolysis can continue and the maximum yield of ATP can be made
What is the formula for respiratory quotients?
RQ
= volume of co2 released / volume of 02 consumed
or
= molecules of co2 released / molecules of 02 consumed
What is the RQ value for proteins ?
=0.9
What RQ value for carbs ?
= 1.0
What is the RQ value for lipids
= 0.7
What does an RQ value of more then 1 show?
That an organism is respiring anaerobically and is short of oxygen.
What is a respiratory substrate?
A biological molecule that can be broken down in respiration to release energy.
In the respirometer practice what is used to absorb Co2?
Soda lime
