carbohydrates 4

Question 1

gluconeogenesis

Answer 1

reverses the 4 irreversible steps of glycolysis.

Question 2

Bypass reactions

Answer 2

1- pyruvate to PEP or Lactate to PEP.
Pyruvate-OAA-malanate-PEP
Lactate-Pyruvate-OAA-PEP

2- fructose-1,6- bisphosphate to fructose-6-phosphate
F-1,6 biP + H20 = F-6-P + Pi
it would favourably energetic to react with ADP to produce ATP
3- glucose-6-phosphate to glucose
G-6-P + H20 = Glucose + Pi
occurs in the ER in order to allow storage of G-6-P inside cell. glucose then moves back into cell

Question 3

Fructose to pyruvate?

Answer 3

Fructose to fructose-1-phosphate. using ATP.
F-1-P to DAH and glyceraldehyde.

Glyceraldehyde to G-3-P using ATP

Question 4

galactose to pyruvate

Answer 4

galactose- galactose-1-phosphate-glucose-1-phosphate.

Uses UDP-galactose which is regenerated later on using UDP-glucose

Question 5

what does phosphate pentose pathway produce?

Answer 5

1-NADPH- used in liver and mammary glands for FA synthesis, in adrenal gland for steroid production, in RBCs as antioxidant

2-Pentoses- precursor for ATP, RNA, DNA

Question 6

how does the phosphate pentose pathway work?

Answer 6

1- oxidative stage-
G-6-P to ribulose-6-phospahate– reversible
produces NADPH for NADP+.

ribulose-6-phophate to nucleotides,DNA- not reversible.

used when lots of NADPH needed e.g. FA synthesis

2- non-oxidative ribulose-6-phosphate to G-6-P.
used for the production of 3-7 long carbon chains.
used when many polymers needed e.g. cell reproduction.

Question 7

when is glyconeogenesis reduced?

Answer 7

during alcohol consumption.
reduces the intake of NAD+.
increases lactiacedemia and hypoglycaemia.
NAD+ is used to convert ethanol to acetylaldehyde and then to acetate
It is needed to convert lactate into pyruvate in the first step of gluconeogenesis.

Question 8

how to reduce PPP

Answer 8

Interrupt activity of G-6-P dehydrogenase.
involved in first irreversible step of PPP.
reduces NADPH in RBCs.
increases percentage of H202 and free radicals in the blood which will weaken the membranes of the RBCs.

Black water fever

Question 9

difference between NAD+ and NADP+?

Answer 9

both involved in electron transport chain.
NAD+ used in metabolism of sugars for gluconeogenesis and citric acid cycle
NADP+ used in anabolic process- turns small molecules into FAs