Glycolysis and Gluconeogenesis 10/8

Question 1

where does glycolysis take place?

Answer 1

cytoplasm

Question 2

products of AEROBIC glycolysis are:

Answer 2

pyruvate and lactate (both!)

Question 3

the 2 phases of glycolysis are

Answer 3

1. preparatory phase

2. ATP generating phase

Question 4

what is the net ATP that gets made in glycolysis

Answer 4

2 ATP (4 total made, 2 were used in the process=2 left over)

Question 5

can glucose leave the cell once it is phosphorylated?

Answer 5

no! thats why it gets phosphorylated - its fate is then determined

Question 6

the most highly regulated step in glycolsis involves which enzyme?

Answer 6

PFK1 (phosphofructokinase 1) makes fructose-6-phosphate into fructose-1,6-bisphosphate. has 4 allosteric binding sites!

Question 7

insulin (promotes/inhibits) glycolysis

Answer 7

promotes

Question 8

glucagon/catecholamines (promote/inhibit) glycolysis

Answer 8

inhibit

Question 9

rate limiting enzyme of glycolysis

Answer 9

PFK1

Question 10

PFK1 exists as ___ isoforms. what are they?

Answer 10

3 isoforms

m-muscle l-liver p-platelets

Question 11

the 2nd irreversible step in glycolysis is

Answer 11

PFK1 catalyzed (fructose-6-phosphate to fructose-1,6-bisphosphate

Question 12

PFK1 is allosterically inhibted by

Answer 12

ATP and citrate

Question 13

PFK1 is allosterically stimulated by

Answer 13

AMP and ADP

Question 14

Whats the BFD about PFK2?

Answer 14

it has both a kinase domain (n-terminus) and phosphatase domain (c-terminus)

Question 15

the PFK2 kinase is active when

Answer 15

dephosphorylated by insulin dependent pathway

Question 16

the PFK2 phosphatase is active when

Answer 16

phosphorylated by glucagon/catecholamine dependent pathway

Question 17

aldolase gene A: highest expression and pathway its important for

Answer 17

highest expression in muscle

important for glycolysis

Question 18

aldolase gene B: highest expression and pathway its important for

Answer 18

highest in gluconeogenic tissues (kidney, liver, intestine)

important for fructolysis, glycolysis, gluconeogenesis

Question 19

aldolase gene C

Answer 19

highest in CNS

Question 20

what is the function of aldolase?

Answer 20

cleaves 6C substrate into 2 3C products

Question 21

phosphoglycerate kinase

Answer 21

1,3-bisphosphoglycerate –> 3-phosphoglycerate +ATP

Question 22

what effect does BPG have on hemoglobin?

Answer 22

causes it to release O2 into tissues (more numerous in areas of high altitudes)

Question 23

pyruvate kinase

Answer 23

phosphoenolpyruvate –>pyruvate

*irreversible, coupled to ATP synthesis

Question 24

pyruvate kinase is allosterically activated by

Answer 24

F-1,6-P

Question 25

pyruvate kinase is allosterically inhibited by

Answer 25

ATP and alanine (indicates theres lots of pyruvate)

Question 26

PKL is inhibited when

Answer 26

phosphorylated

Question 27

NAD has to be regenerated. the shuttles to bring it back to the mitochondria are:

Answer 27

1. glycerol-phosphate

2. malate-aspartate

Question 28

which isoform of lactate dehydrogenase favors formation of lactate and NAD?

Answer 28

LDHA

Question 29

which isoform of lactate dehydrogenase favors formation of pyruvate and NADH?

Answer 29

LDHB (LDH1) - in heart attacks, high serum LDH1

Question 30

malata/aspartate shuttle

Answer 30

a way of regenerating NADH/NAD so that NAD can be used in glycolysis

Question 31

what are the substrates for gluconeogenesis?

Answer 31

amino acids, lactate, glycerol

Question 32

what is gluconeogenesis?

Answer 32

synthesis of glucose from non-carbs

Question 33

3 irreversible steps of gluconeogenesis are:

Answer 33

1. pyruvate –>PEP via OAA (catalyzed by PC and PCK)
2. dephosphorylation of fructose-1,6-bisphosphate by FBPase 1
3. dephosphorylation of glucose-6-phosphate by G6Pase