C18? - Respiration Flashcards
Where does glycolysis occur?
Cytoplasm of the mitochondria
Outline the steps of glycolysis
Glucose converted to Hexose bisphosphate (2ATP –> 2ADP +2Pi)
Hexose bisphosphate splits to 2TP
Each TP converted to Pyruvate (each using 2ADP and 1NAD+)
What is the net produce of glycolysis for 1 molecule of glucose
2 pyruvate
2 NADH
2ATP
What happens to the pyruvate after glycolysis?
Actively transported to mitochondrial matrix where it enters the link reaction
Outline the link reaction
Pyruvate converted to acetyl group (1 CO2 removed, 1 NAD+–> NADH)
Combined with Coenzyme A to make acetyl-CoA
What is the net produce of the link reaction for 1 molecule fo glucose
2 acetyl-CoA
2 CO2
2 NADH
Outline the Krebs cycle
Acetyl group delivered by Acetyl-CoA
Combined with oxaloacetate to make citrate
Citrate loses a CO2 and makes an NADH to make a 5C compound
5C looses a CO2, makes an NADH and an ATP to make a 4C compound
4C compound makes NADH and FADH2 to regenerate oxaloacetate
What type of reaction is ATP made in during glycolysis and the Krebs cycle
substrate level phosphorylation
What type of reaction happens to turn pyruvate into an acetyl group
Oxidative decarboxylation
What are the net products of the Krebs cycle for 1 molecule of glucose
4 CO2
6 NADH
2 FADH2
2ATP
What happens to the NADH produced glycolysis, link and krebs reactions?
oxidised by electron transport chain
Where does oxidative phosphorylation occur?
inner membrane of mitochondria (folded in cristae)
What happens in oxidative phosphorylation (up to end of ETC)?
H atoms carried to ETC by NADH and FADH2, H atoms dissociate into H+ and e-
passed along a series of electron carriers
oxygen acts as terminal receptor
What happens to the energy released in the ETC (oxidative phosphorylation)
energy released used to pump h+ ions across inner mitochondrial membrane into intermembrane space
creates electrochemical gradient
ions diffuse back via chemiosmosis through channel proteins containing ATP synthase
ATP synthesised
makes 34 molecules of ATP
What is anaerobic respiration?
repsiration in the absences of oxygen
Why can aerobic respiration not occur in the absence of oxygen?
No terminal receptor in ETC, casues “back up” of electrons, therefore NAD+ (and FAD) can not be regenerated for glycolysis
What are facultative anaerobes?
organisms that can respire both aerobically and anaerobically
What is fermentation?
anaerobic repsiration without the involvement of the ETC
What are obligate anaerobes
organisms that can only respire anaerobically
What are obligate aerobes
organisms that can only respire aerobically
What are the types of anaerobic repsiration and where do they occur?
Lactate fermentation (mammals) Alcoholic fermentation (plants and yeast)
Outline the steps of lactate fermentation
Pyruvate reduced to lactate (NADH –> NAD+)
catalysed by lactate dehydorgenase
What are the advantages of lactate fermentation
one step, quick reaction
allows 2ATP to be produced per glucose (when preparation would otherwise stop)
How is lactic acid removed from respiring tissues
oxidised back into pyruvate
converteed into glucose in liver (oxygen is required thus causing oxygen debt)
Outline the steps of alcoholic fermentation
Pyruvate
CO2 removed (catalysed by pyruvate decarboxylase)
Ethanal
reduced to ethanol (NADH –> NAD+)
What are the negatives of alcoholic fermentation?
Non reversible
ethanol is toxic and will cause death
How do you calculate the respiratory quotient (RQ)
CO2 produced/ O2 consumed
What equipment is used to calculate the RQ
Respirometer
What is the RQ for carbohydrates eg. glucose
1.0
What is the RQ for proteins
0.9
What is the RQ for lipids
0.7
What is the RQ when anaerobic respiration occurs? Why?
> 1
CO2 produced but less O2 consumed
How would you calculate the rate of respiration of a small organism eg. maggots?
Place in test tube on guaze
Sodalime underneath
Place a bung connected to graduated tube with coloured liquid
CO2 produced dissolves in sodalime
O2 produced causes a decrease in pressure, draws in air thus coloured liquid moves
