IMMS ENERGY PRODUCTION Flashcards Preview

PHASE 1 REVISION GUIDE > IMMS ENERGY PRODUCTION > Flashcards

Flashcards in IMMS ENERGY PRODUCTION Deck (63)
Loading flashcards...
1

where does glycolysis take place?

in the cytosol of the cell

2

what is the rate limiting step of gylcolysis controlled by?

phosphofructoskinase -1
it is also controlled by levels of ATP and AMP

3

which part of energy production is affected by insulin and glucagon?

glycolysis

4

can glycolysis take place in aerobic or anaerobic conditions?

aerobic and anaerobic conditions

5

what is produced by glycolysis?

4ATP

2NADH - enters electron transport chain and can produce a further 6ATP

6

where does the krebs (TCA) cycle take place?

in the matrix of the mitochondria

7

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

8

what is the rate limiting step of the Kreb's cycle controlled by?

isocitrate dehydrogenase

the rate is also determined by levels of ATP, NADH and FADH2 - high levels inhibit the krebs cycle

9

what activates the Kreb's cycle?

high levels of ADP

10

what happens if the kreb's cycle is inhibited?

there is a build-up of acetyl-CoA which then undergoes fatty acid synthesis

11

where does oxidative phosphorylation occur?

across the inner membrane of the mitochondria

12

what is the role of complex I in the electron transport chain?

it removes electron from NADH

13

what is the role of complex II in the electron transport chain?

removes electrons from FADH2 in the presence of co-enzyme Q (ubiquinone)

14

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

15

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

16

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

17

where does fatty acid synthesis occur?

in the cytosol of the cell

18

what is the process of fatty acid synthesis?

citrate shuttle

19

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

20

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

21

give some examples of fatty acids?

linoleic acid
oleic acid
palmitic acid
arachidonic acid

22

when does fatty acid metabolism occur?

it occurs in response to decreased blood glucose and high glucagon

23

what is fatty acid metabolism?

it is a method of breaking down fatty acids to produce energy
involved carnitine shuttle and beta oxidation

24

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

25

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

26

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

27

what does each round of beta-oxidation of fatty acids produce?

1 NADH
1 FADH2
1 acetyl CoA - re-enters krebs cycle

28

when does ketone production occur?

- usually occurs slowly during normal feeding and normal physiological status
- increases in response to carbohydrate shortages

29

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

30

which tissues use ketone bodies?

can only be used by cardiac and skeletal muscle
the ketone bodies are used in preference to carbohydrates to preserve glucose