citric acid cycle

Question 1

what are two other synonyms for the citric acid cycle?

Answer 1

TCA cycle and krebs cycle

Question 2

where about in the cell does the citric acid cycle take place?

Answer 2

in the mitochondrial matrix

Question 3

what is the basic mechanism of events in the citric acid cycle?

Answer 3

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.

Question 4

How is pyruvate converted to acetyl coA?

Answer 4

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.

Question 5

what vitamin does coA contain?

Answer 5

pantothenic acid (vitamin B5)

Question 6

how many molecules of NADH are formed in the citric acid cycle?

Answer 6

3

Question 7

how many molecules of FADH2 are formed in krebs cycle?

Answer 7

1

Question 8

how many molecules of Co2 are produced in the TCA cycle?

Answer 8

2

Question 9

what vitamin is Flavin Adenine Dinucleotide (FAD) formed from?

Answer 9

vitamin B2

Question 10

what does a deficiency in vitamin B2 result in?

Answer 10

lesions of the mucous membrane (cracked, sore lips and corners of the mouth; similar lesions of the genital region, swollen and tender tongue)

Question 11

what process results in the formation of NADH from kept acids in the TCA cycle?

Answer 11

DEHYDROGENATION reactions

Question 12

what process results in the formation of CO2 in the citric acid cycle?

Answer 12

decarboxylation of kept acids (as they are quite reactive)

Question 13

where about in the mitochondria does the respiratory chain/electron transfer occur?

Answer 13

on the inner mitochondrial membrane

Question 14

what is the basic mechanism of events which occur in the respiratory chain?

Answer 14

electrons are fed into the system by NADH and FADH2 at different points and these electrons are passed down the chain slowly releasing energy.

Question 15

which antibiotic targets the respiratory chain?

Answer 15

antimycin A

Question 16

which step of the TCA cycle do carbon monoxide and cynanide block?

Answer 16

the final step by which hydrogen combines with oxygen

Question 17

which insecticide targets the respiratory chain?

Answer 17

rotenone

Question 18

how is an electrochemical gradient generated across the inner mitochondrial membrane?

Answer 18

protons (H+) are passed out of the membrane by the major proteins of the respiratory chain: positive outside the membrane, negative inside the membrane.

Question 19

what are the three main proteins of the electron transfer pathway?

Answer 19

NADH-Q reductase,
cytochrome reductase
cytochrome oxidase

Question 20

how is this electrochemical gradient used to generate ATP?

Answer 20

ATP synthase (trans-membrane channel protein) allows protons back into the matrix down a steep concentration gradient and uses tis energy to generate ATP

Question 21

how many molecules of ATP are produced by oxidation of each NADH molecule?

Answer 21

3

Question 22

how many molecules of ATP are produced by oxidation of each molecules of FADH2?

Answer 22

2

Question 23

how many molecules of ATP are produced in total?

Answer 23

32