Biochemistry: glycolysis, TCA cycle & oxidative phosphorylation

Question 1

what are the products of aerobic glycolysis

Answer 1

2pyruvate + 4ATP + 2H20 + 2NADH + 2H+

Question 2

what are the products of anaerobic glycolysis

Answer 2

lactic acid + 2ATP

Question 3

how is glycolysis regulated at substrate level

Answer 3

by hexokinase( glucose to glucose-6-phosphate)

Question 4

how is glycolysis regulated at rate level

Answer 4

by phosphofructokinase

Question 5

how is glycolysis regulated at product exit level

Answer 5

by pyruvate kinase( inhibited by ATP)

Question 6

how is glycolysis activated

Answer 6

by AMP and frucotse-2,6-biphosphate

when energy is needed

Question 7

how is glycolysis inhibited

Answer 7

by ATP/citrate(excess energy), by H+(excess lactic acid)

Question 8

where does TCA cycle take place

Answer 8

mitochondrial matrix

Question 9

how does pyruvate enter matrix

Answer 9

via H+/pyruvate symporter

Question 10

pyruvate is converted to what substance that goes into the TCA cycle, and by what enzyme

Answer 10

converted to acetyl CoA via pyruvate dehydrogenase complex

Question 11

what are the products of the TCA cycle

Answer 11

2CO2, 3NADH+, H+, FADH2, ATP

Question 12

what is one glucose molecule equivalent to in pyruvate

Answer 12

= 2 pyruvate( i.e. 2ATP)

Question 13

how does NADH enter the matrix

Answer 13

via malate-aspartate shuttle

Question 14

where are all enzymes found in the matrix, with one exception

Answer 14

ALL found in inner membrane of matrix, except succinate dehydrogenase

Question 15

what is the TCA cycle inhibited by

Answer 15

ATP, NADH, acetyl-CoA( excess energy)

Question 16

what is the TCA cycle activated by

Answer 16

ADP, NAD+( need energy)

Question 17

what is redox potential

Answer 17

the electron transfer potential

Question 18

describe the redox potential of NADH+/FADH2 and of O2/H2O

Answer 18

NADH+/FADH2 has -ve redox potential, tend to donate electrons( strong reducers)
O2/H2O has +ve redox potential( strong oxidisers)

Question 19

describe how the electron transport chain works

Answer 19

electrons passed along chain, O2 is final acceptor( forms H2O)
this process produces energy, used to pump H+ across inner matrix
H+ flows back through ATP synthase to produce ATP

Question 20

how much ATP is produced per glucose molecule by oxidative phosphorylation, and what does it depend on

Answer 20

30-32 ATP, depending on the phosphate/oxygen ratio