citric acid cycle (kreb's cycle)

what is the citric acid cycle?

8 enzymatic reactions which create a biochemical pathway used to generate energy for the body

biochemical processes of the kreb’s cycle:

> oxidation of Acetyl CoA

> synthesis of NADH

> production of amino acids

citric acid cycle is an:

aerobic pathway requiring oxygen

where does the kreb’s cycle take place?

in the mitochondria of eukaryotic cells

preparatory step of the kreb’s cycle:

glycolysis (glucose is converted into pyruvate)

pyruvate dehydrogenase in the krebs cycle:

converts pyruvate into acetyl CoA

pyruvate dehydrogenase produces:

CO2 and NADH molecules

oxaloatate combines with the acetyl CoA and forms:

citrate

when citrate is formed what is enzyme involved in the process?

citrase synthase

acetyl CoA no. carbons:

2C

oxaloatate no. carbons

4C

citrate no. carbons:

6C

citrate is then converted into:

isocitrate

isocitrate is formed by:

isomerisation by the aconitase enzyme

isocitrate is then oxidised into:

alpha-ketoglutarate

alpha-ketoglutarate is oxidised by:

isocitrate dehydrogenase enzyme

isocitrate dehydrogenase produces:

NAD (converts to NADH) and CO2

isocitrate dehydrogenase additional function:

rate limiting step in the kreb’s cycle - determines speed

what slows the cycle via isocitrate dehydrogenase:

high ATP and NADH in cell

what speeds up the cycle via isocitrate dehydrogenase:

high ADP in the cell

alpha-ketoglutarate is then converted into:

succinyl CoA

alpha-ketoglutarate is converted by which enzyme?

alphaketoglutarate dehydrogenanse

alphaketoglutarate dehydrogenase produces:

NAD (converts to NADH) and CO2

alphaketoglutarate dehydrogenase requires:

vitamin B1,2,3,5 and lipoic acid

succinyl CoA is then converted into:

succinate

succinate is formed by:

succinyl CoA synthase

succinyl CoA synthase produces:

GTP s

succinate is then converted into:

fumrate

fumrate is converted by:

succinate dehydrogenase

succinate dehydrogenase produces:

QH2 (which converts to FADH 2)

fumrate is then converted into:

malate

malate is converted by:

fumrase

malate is then converted back into:

oxaloatate

malatate > oxaloatate via:

malate dehydrogenase

malate dehydrogenase produces:

NAD which converts to NADH

in the citric acid cycle which molecules are produced?

1 GTP, 1 FDAH2, 2 CO2 and 3 NADH

cycle speeds up when:

body needs more energy

cycle slows down when:

body needs less energy

acetyl CoA sources:

triglycerides, saccharides, proteins and alcohol

how many ATP are produced during the kreb’s cycle?

24