Chapter 3 Study Questions (Part 5)

Question 1

how does the lack of oxygen affect ETC? why?

Answer 1

can’t oxidize the last two transporters. shuts down.

Question 2

how does the lack of oxygen affect chemiosmosis? why?

Answer 2

shuts down.

Question 3

how does the lack of oxygen affect the TCA cycle?

Answer 3

shuts down. no pyruvate means FADH2 and NADH depleted, means no acetyl CoA, means can’t be oxidized.

Question 4

how does lack of oxygen affect glycolysis and why?

Answer 4

nothing happens. it’s unaffected because glycolysis doesn’t use O2.

Question 5

why does pyruvate build up in cells under anaerobic conditions?

Answer 5

not converted to acetyl, gets reduced to lactate instead.

Question 6

what is the role of lactic acid fermentation?

Answer 6

regenerate NAD to keep glycolysis going. lactate is byproduct of it, that’s it.

Question 7

when would we want to regenerate NAD+ ?

Answer 7

to run glycolysis under low oxygen conditions

Question 8

describe the effect of regenerating NAD+ on O2 and CO2 levels

Answer 8

no O2 required, no CO2 produced

Question 9

when tissue gets reoxygenated, what happens first?

Answer 9

ETC –> chemiosmosis –> oxidative phosphorylation

Question 10

when tissue gets reoxygenated, what happens to NADH and FADH2?

Answer 10

they get oxidized

Question 11

when tissue gets reoxygenated, what happens second?

Answer 11

TCA

Question 12

when tissue gets reoxygenated, what happens to pyruvate levels and why?

Answer 12

you get back the pyruvate you lost earlier. it’s a reversible reaction taking place due to the law of mass action.

Question 13

why is the amount of ATP produced from NADH made in glycolysis not always the same?

Question 14

what happens after Fructose-1,6-Bisphosphate is made?

Answer 14

after F-1,6-BP is made, NADH passes its two electrons to make glycerol 3-phosphate. a transporter takes G3P across the outer mitochondrial membrane. pushing e- from NADH into cytosol, past the first mitochondrial membrane.

G3P passes the two electrons to make FAD to make FADH2, which remain embedded in the inner mitochondrial membrane

Question 15

what does FADH2 do with its 2e-?

Answer 15

passes them to coenzyme Q in the inner mitochondrial membrane.

Question 16

where is coenzyme Q located? why is that significant?

Answer 16

at stage 2. cause stage 2 does not pump H+. proton pumps that make the proton gradient are only located at ETC stages 1,3,4

Question 17

what happens to the e- that get unloaded at stage 2 of the ETC? why is that significant?

Answer 17

they only power the H+ pumps at stages 3 and 4. this produces a smaller proton gradient, and less protons to run through ATP synthase for ATP production

Question 18

which pathway of cellular respiration produces ATP the quickest?

Answer 18

glycolysis

Question 19

which pathway of cellular respiration produces the most ATP?

Answer 19

oxidative phosphorylation

Question 20

why is it said that triglycerides are guilt for energy storage?

Question 21

what are the different sources for gluconeogenesis?

Answer 21

1 is glycogen, glycerol.

minor: glycerol, lactate.

starvation conditions: protein.

Question 22

why can’t arbon from fatty acids be used to make glucose in gluconeogenesis?

Answer 22

carbons are lost as CO2

Question 23

why can’t acetyl CoA made from pyruvate be used to make glucose?

Answer 23

large NEGATIVE delta G aka not reversible!

Question 24

how can a protein be used to make glucose?

Answer 24

by recycling amino acid intermediates into the TCA cycle to make glucose

Question 25

what hormone is released in response to low blood glucose?

Answer 25

glucagon

Question 26

why do we need to maintain blood glucose levels?

Answer 26

body prefers glucose as energy source. especially brain. RBCs only do glycolysis

Question 27

what is B-oxidation?

Answer 27

B carbon is oxidized by exchanging the H for a doubled bond O

Question 28

why does excessive B-oxidation lead to keton body formation?

Answer 28

CoA removes one 2C acetyl group and leaves behind a new COOH end

Question 29

why does excessive B-oxidation lead to ketone body formation?

Answer 29

CoA removes one 2C acetyl group and leaves behind a new COOH end

Question 30

why is excessive ketone body formation potentially dangerous?

Answer 30

super acidic, can be lethal. overwhelms TCA and can’t go backwards.

Question 31

what energy soure can be used to make acetyl CoA to feed the TCA cycle?

Answer 31

at the beginning: glucose and fatty acids

in the middle: glucose, fatty acids, protein

Question 32

what is the warburg effect?

Answer 32

accelerated glycolytic pathway. the activity of major enzymes is accelerated.

Question 33

what are the three major enzymes involved in the glycolytic pathway?

Answer 33

PFK

pyruvate kinase

hexokinase

Question 34

what effect would a compound that inhibits PFK have on tumor growth and why?

Answer 34

limit PFK, limit speeding up back half

Question 35

what effect would a compound that inhibits pyruvate kinase have on tumor growth and why?

Answer 35

it’s like reverse mass action: slows down back half

Question 36

what does phosphofructokinase do?

Answer 36

rate determining step, mass action, commits glucose

Question 37

what does pyruvate kinase do?

Answer 37

intermediate of the front half speeds up the back half