Flashcards in IMMS ENERGY PRODUCTION Deck (63)
where does glycolysis take place?
in the cytosol of the cell
what is the rate limiting step of gylcolysis controlled by?
it is also controlled by levels of ATP and AMP
which part of energy production is affected by insulin and glucagon?
can glycolysis take place in aerobic or anaerobic conditions?
aerobic and anaerobic conditions
what is produced by glycolysis?
2NADH - enters electron transport chain and can produce a further 6ATP
where does the krebs (TCA) cycle take place?
in the matrix of the mitochondria
what is produced by one cycle of the kreb's cycle?
3 NADH - 9 ATP
1 FADH2 - 2 ATP
1 GTP - 1 ATP
it produces 12 ATP overall
what is the rate limiting step of the Kreb's cycle controlled by?
the rate is also determined by levels of ATP, NADH and FADH2 - high levels inhibit the krebs cycle
what activates the Kreb's cycle?
high levels of ADP
what happens if the kreb's cycle is inhibited?
there is a build-up of acetyl-CoA which then undergoes fatty acid synthesis
where does oxidative phosphorylation occur?
across the inner membrane of the mitochondria
what is the role of complex I in the electron transport chain?
it removes electron from NADH
what is the role of complex II in the electron transport chain?
removes electrons from FADH2 in the presence of co-enzyme Q (ubiquinone)
what is the role of complexes III, IV and cytochrome C in the electron transport chain?
they donate electrons to cytochromes containing iron
at decreasing energy levels
what happens in the electron transport chain?
electrons move down the chain at decreasing energy levels
this provides energy for H+ to be pumped from intermembranous space to matrix
this H+ movement requires ADP + Pi -> ATP
H+ reacts with O2 released and produces H2O
1/2O2 + 2H+ -> H2O
when does fatty acid synthesis occur?
when there is an abundance of energy - high ATP levels inhibit the kreb's cycle and leads to a build up of acetyl CoA
where does fatty acid synthesis occur?
in the cytosol of the cell
what is the process of fatty acid synthesis?
what happens in the citrate shuttle of fatty acid synthesis?
- oxaloacetate binds with acetyl CoA to produce citrate
- this crosses the mitochondrial membrane into cytosol
- citrate ligase converts citrate back to oxaloacetate
- this is broken down into pyruvate and acetyl CoA
pyruvate is recycled back into mitochondria and converted back into oxaloacetate and re-enters kreb's cycle
- acetyl CoA is converted into fatty acids
why is the citrate shuttle required in fatty acid synthesis?
fatty acid synthesis occurs in cytosol but acetyl CoA cannot pass through the mitochondrial membranes
therefore a citrate shuttle is required
give some examples of fatty acids?
when does fatty acid metabolism occur?
it occurs in response to decreased blood glucose and high glucagon
what is fatty acid metabolism?
it is a method of breaking down fatty acids to produce energy
involved carnitine shuttle and beta oxidation
why is the carnitine shuttle required for fatty acid metabolism?
- dietary fatty acids tend to have more than 14 carbons
- fatty acids longer than 12 carbons cannot diffuse through mitochondrial membrane and must be transported by the carnitine shuttle
what happens in the carnitine shuttle in fatty acid metabolism?
- fatty acids (acyl CoA) are converted to acyl carnitine by carnitine acyltransferase 1 (CAT-1) on mitochondrial membrane
- the CoA released is recycled
- acyl carnitine diffuses through the membrane
- acyl carnitine is reformed into acyl CoA by carnitine acyltransferase 2 (CAT-2) on the interior side of the membrane
- the carnitine is recycled through the outer membrane of mitochondria
what happens in beta-oxidation of fatty acids?
- once acyl CoA has crossed mitochondrial membrane it can now be oxidised
- this involves the sequential removal of 2 carbon units by oxidation - the beta carbon is cleaved
- each round of beta-oxidation produces 1 NADH, 1 FADH2 and 1 acetyl CoA
- the acetyl CoA re-enters the kreb's cycle
- ATP is produced
what does each round of beta-oxidation of fatty acids produce?
1 acetyl CoA - re-enters krebs cycle
when does ketone production occur?
- usually occurs slowly during normal feeding and normal physiological status
- increases in response to carbohydrate shortages
why does ketone production increase in response to carbohydrate shortages?
this is due to increased beta-oxidation and the production of acetyl CoA which exceeds the limit of the kreb's cycle