Biochem Lecture 19

Front 1

Which intermediate in glycolysis is converted to Pentose-5-Phosphate?

Back 1

Glucose-6-Phosphate

Front 2

Two important products of the pentose phosphate pathway are ___________ and ____________

Back 2

-ribose-5-phosphate (for NT synthesis)

-NADPH (need to reduce glutathione,synthesize fatty acids, NO, steroids/sterol, detoxify)

Front 3

In the first part of the oxidative step of the pentose phosphate pathway, _______ is converted to _______ by __________. This step makes one molecule of _______.

Back 3

-Glucose-6-Phosphate

-6-phosphogluconate

-Glucose-6-phosphate dehydrogenase

-NADPH

Front 4

In the second part of the oxidative step of the pentose phosphate pathway, 6-Phospho-Gluconate is converted to __________ by ____________. This step makes ______ & ______.

Back 4

-Ribulose-5-Phosphate

-6-Phospho-Gluconate Dehydrogenase

-NADPH & CO2

Front 5

NAD is used in ______ reactions, while NADPH is used in ______ reactions.

Back 5

-oxidative

-reductive

Front 6

Ratio of NADP+/NADPH in resting cell

Back 6

very low b/c NADPH is the form used for the reductions

Front 7

In the second, non-oxidative, phase of pentose phosphate pathway, ribulose-5-phosphate is rearranged by __________ to make Ribose 5 Phosphate & by _______ to make Xylulose 5 Phosphate

Back 7

-Isomerase

-Epimerase

Front 8

In the second, non-oxidative, phase of pentose phosphate pathway, ribulose-5-phosphate is rearranged by Isomerase to make __________ & by Epimerase to make ____________

Back 8

-Ribose 5 Phosphate

-Xylulose 5 Phosphate

Front 9

Transketolase transers ____ carbon units, using _______. This can be associated with which disease?

Back 9

-2

-thiamine

-Wernicke-Korsakoff Syndrome

Front 10

___________ transers 2 carbon units, using _______.

Back 10

-Transketolase

-Thiamine

Front 11

Transketolase can convert _________ to ribose-5-phosphate

Back 11

Xyulose-5-Phosphate

Front 12

Transaldolase transfers ___ carbon units.

Back 12

3

Front 13

________ transfers 3 carbon units.

Back 13

Transaldolase

Front 14

In the second, non-oxidative, phase of the pentose phosphate pathway the ________ skeletons are rearranged

Back 14

carbon

Front 15

The pentose phosphate pathway is a shunt because Xylulose 5 Phosphate & Ribose 5 Phosphate (3 pentose phosphates) can be eventually turned back into 1 _______ (triose) & 2 _______ (hexose) molecules

Back 15

-glyceraldehyde-3-phosphate

-fructose-6-phosphate

Front 16

If you want about as much NADPH as ribose produced what should your end product of the PP shunt be?

Back 16

-Ribose-5-phosphate

Front 17

If you're sufficient in NADPH, but need ribose you should change __________ & ___________ into Ribose-5-Phosphate

Back 17

-Fructose-6-Phosphate

-Glyceraldehyde-3-Phosphate

Front 18

If you need lots of NADPH (under oxidative stress), but not lots of ribose how should you run the PP shunt? (basically you need to regenerate _________)

Back 18

-run the path and after converting ribose-5-phosphate to glyceraldehyde-3-phosphate & fructose-6-phosphate in the end --> run up gluconeogenesis so you regenerate glucose-6-phosphate

-glucose-6-phosphate

Front 19

If you need a little more NADPH than ribose-5-phosphate what should your end product of the shunt be?

Back 19

-convert ribose-5-phosphate into glyceraldehyde-3-phosphate & fructose-6-phosphate

Front 20

_______ is the regulated step of the PP shunt

Back 20

Glucose-6-Phosphate Dehydrogenase

Front 21

PP shunt is inducible by insulin because you need _____ to make ______

Back 21

-NADPH

-Fatty Acids

Front 22

PP shunt is allosterically inhibited by ________

Back 22

NADPH

Front 23

The ________, rate limiting step, in the PP shunt is not very active b/c it is inhibited by NADPH & has high Km & low Ki

Back 23

Glucose-6-Phosphate Dehydrogenase

Front 24

Fenton & Haber-Weiss Reactions are involved with what?

Back 24

formation of reactive oxygen species

Front 25

__________ converts Superoxide to Hydrogen Peroxide

Back 25

Superoxide Dismutase (SOD)

Front 26

Superoxide Dismutase (SOD) converts ___________ to ____________

Back 26

-Superoxide

-Hydrogen Peroxide

Front 27

________ is required for reduction of peroxides

Back 27

Glutathione (GSH) peroxidase

Front 28

Glutathione (GSH) peroxidase is required for reduction of ________

Back 28

peroxides

Front 29

NADPH produced by ___________ maintains the supply of reduced _______ needed to destory peroxide

Back 29

-Glucose-6-Phosphate Dehydrogenase

-glutathione

Front 30

__________ reduces the oxidized glutathione in the cell generated from _________

Back 30

-Glutathione (GSSG) Reductase

-Glutathione (GSH) peroxidase

Front 31

Glucose Oxidase measures what?

Back 31

-converts hydrogen peroxide to water in order to measure the level of hydrogen peroxide in the blood

-need very small volume of blood

Front 32

Why do "Heinz bodies" (precipitation of hemoglobin) in RBCs occur with a G6PD deficiency?

Back 32

-NADPH is not generated & therefore glutathione cannot be reduced back from it's oxidized form

-cell is no longer in reducing conditions & proteins can aggregate

Front 33

How does G6PD deficiency help with malaria?

Back 33

-because life cycle of RBCs is so little now

Front 34

If other cells have malic enzyme to generate NADPH (in addition to PP shunt), why can't red blood cells?

Back 34

-because they don't have malate & the TCA cycle