Energy transfers: Respiration Flashcards
which two stages of respiration take place in the matrix
link reaction and krebs cycle
name and explain the two ways that ATP can be generated
- substrate level phosphorylation: directly generated in glycolysis and krebs cycle
- oxidative phosphorylation: energy released when a reduced hydrogen carrier or coenzyme ( NADH2 , FADH2) has been oxidised at the electron carrier chain
where does glycolysis take place and what does it involve
- in the cytoplasm
- involves conversion of glucose into
2x pyruvate
2x NADH2
2X ATP
explain the steps of glycolysis
- glucose is stable so is activated ny phosphorylation.
- through hydrolysis of 2x ATP
- glucose phosphate then splits into 2x triose phosphate
- which is oxidised to pyruvate and involves the loss of Hydrogen
- which reduces NAD to NADH2 via SLP
describe what happens in the link reaction
- happens in the presence of oxygen
- pyruvate is actively transported into the mitochondrial matrix
explain the steps of link reaction
- pyruvate is oxidised to acetate and the hydrogen removed is used to reduce the hydrogen carrier NAD into NADH2
- carbon dioxide is lost (decarboxylation)
- then a molecule of coenzyme A is required
- to make acetyl-coenzyme A
- HAPPENS TWICE PER GLUCOSE-PYR
what are the products of link reaction
- NO ATP USED OR MADE
- 2x NADH2
- 2x acetyl co A
- CO2
The Krebs Cycle yields
- 2x CO2
- some ATP produced by SLP
- 3x NADH
- 1x FADH2
2 ACETYL CO-A PER MOLECULE OF GLUCOSE
Explain the electron transport chain
- Reduced NAD and FAD are oxidised losing hydrogen
- the electrons from H pass down the electron carriers within the mitochondrial membranes in a series of REDOX reactions
- electrons lose energy used to pump the H+ protons into intermembrane space
- some energy is also lost as heat
- H+ facilitated diffuse down a proton gradient across the inner membrane into the matrix VIA ATP synthase
- the electrons and H+ recombine with oxygen gas to form water
- oxygen is the final electron acceptor
water is a waste product of aerobic respiration. describe how water is formed at the end of aerobic respiration
- oxygen is terminal/final electron acceptor
- combines with electrons and protons
describe the roles of the coenzymes and carrier proteins in the synthesis of ATP
1- reduced NAD/FAD attached to NAD/FAD
2- electrons transferred from carrier to carrier
3- energy released as electrons passed on
4- energy used to synthesise ATP from ADP+Pi
5- H+ pumped into intermembrane space
6- H+ diffuse back through ATP synthase enzyme
describe how ATP is made in mitochondria
1- substrate level phosphorylation /ATP produced in krebs cycle
2- kreb sycle/link reaction produces reduced NAD/FAD
3- electrons pass along the ETC
5- energy is released
6- protons pumped into the intermembrane space
7- ADP +Pi
8- ATP synthase
describe the events of oxidative phosphorylation
1- hydrogen attached to NAD/FAD
2- ETC on cristae/ inner membrane
3- electrons transferred via a series of redox reaction
4- energy released as e- passed on
5- protons pumped into inner membrane space
6- protons flow back through stalked particles/enzymes
7- energy used to to syntheise ATP using ATP synthase
describe how oxidation takes place in glycolysis and in the krebs cycle
-removal of hydrogen (dehydrogenation)
- by enzymes (dehydrogenase)
- H accepted by NAD
- in krebs cycle, FAD used as well
what happens during anaerobic respiration
- link reaction , krebs cycle and ETC stop as there is no oxygen to act as the final electron acceptor
- glycolysis does not involve oxygen but NAD must be regenerated to continue
- H from reduced NAD in glycolysis is accepted by pyruvate rather than passing thru ETC
- pyruvate is reduced to lactate in animals and ethanol & CO2 in plants
