citric acid cycle Flashcards
what are two other synonyms for the citric acid cycle?
TCA cycle and krebs cycle
where about in the cell does the citric acid cycle take place?
in the mitochondrial matrix
what is the basic mechanism of events in the citric acid cycle?
acetyl coA (2-carbon) is combined with oxaloacetate (4 carbons) to form a 6 carbon molecule. This 6 carbon molecule is then broken down in a series of events who eventually regenerates the oxalacetate.
How is pyruvate converted to acetyl coA?
CoA is a nucleotide that forms high energy bonds with carboxylic acids. Pyruvate is oxidised to acetate by passing electrons and hydrogen to NAD+ and producing one molecule of CO2.
what vitamin does coA contain?
pantothenic acid (vitamin B5)
how many molecules of NADH are formed in the citric acid cycle?
3
how many molecules of FADH2 are formed in krebs cycle?
1
how many molecules of Co2 are produced in the TCA cycle?
2
what vitamin is Flavin Adenine Dinucleotide (FAD) formed from?
vitamin B2
what does a deficiency in vitamin B2 result in?
lesions of the mucous membrane (cracked, sore lips and corners of the mouth; similar lesions of the genital region, swollen and tender tongue)
what process results in the formation of NADH from kept acids in the TCA cycle?
DEHYDROGENATION reactions
what process results in the formation of CO2 in the citric acid cycle?
decarboxylation of kept acids (as they are quite reactive)
where about in the mitochondria does the respiratory chain/electron transfer occur?
on the inner mitochondrial membrane
what is the basic mechanism of events which occur in the respiratory chain?
electrons are fed into the system by NADH and FADH2 at different points and these electrons are passed down the chain slowly releasing energy.
which antibiotic targets the respiratory chain?
antimycin A
which step of the TCA cycle do carbon monoxide and cynanide block?
the final step by which hydrogen combines with oxygen
which insecticide targets the respiratory chain?
rotenone
how is an electrochemical gradient generated across the inner mitochondrial membrane?
protons (H+) are passed out of the membrane by the major proteins of the respiratory chain: positive outside the membrane, negative inside the membrane.
what are the three main proteins of the electron transfer pathway?
NADH-Q reductase,
cytochrome reductase
cytochrome oxidase
how is this electrochemical gradient used to generate ATP?
ATP synthase (trans-membrane channel protein) allows protons back into the matrix down a steep concentration gradient and uses tis energy to generate ATP
how many molecules of ATP are produced by oxidation of each NADH molecule?
3
how many molecules of ATP are produced by oxidation of each molecules of FADH2?
2
how many molecules of ATP are produced in total?
32
