Lecture Citric Acid Cycle (Exam #3)

Question 1

TPP undergoes

Answer 1

oxidative decarboxylation

Question 2

What in the active site of the PDH kinase adds the Pi?

Answer 2

Ser-OH

Question 3

Acetyl CoA along with ________ is converted to _____

Answer 3

oxaloacetate; citrate

Question 4

What is activated by acetyl CoA

Answer 4

pyruvate carboxylase

Question 5

What is a reaction used to replenish CAC?

Answer 5

anaploretic reaction

Question 6

Why is acetate and oxaloacetate joined together?

Answer 6

because the enzyme can only do alpha or beta cleavage

Question 7

Acetyl CoA can be generated by break down of?

Answer 7

fatty acids and amino acids

Question 8

Citrate Synthase

Answer 8

converts oxaloacetate & acetate to citrate

Question 9

What type of mechanism does citrate synthase use?

Answer 9

ordered sequential mechanism

Question 10

Describe the mechanism of citrate synthase? (5 steps)

Answer 10

OA binds first (CS closes)
Acetyl CoA binds (CS closes more)
Citryl CoA made (CoA with citrate)
CoA released with water
citrate is made

Question 11

What is Citryl CoA? Is it stable?

Answer 11

CoA with citrate; NO

Question 12

Why does citrate synthase close tighter and tighter?

Answer 12

because it doesn’t want to lose the acetate by letting H2O in

Question 13

Citrate is converted to isocitrate via

Answer 13

aconitase

Question 14

Isocitrate is converted to ______ via ______

Answer 14

alpha ketoglutarate (KG); isocitrate dehydrogenase

Question 15

Isocitrate dehydrogenase

Answer 15

oxidative decarboxylation
undergoes alpha cleavage
irreversible

Question 16

What make isocitrate dehydrogenase slow?go?

Answer 16

ATP/NAPH- slow

ADP/NAD+-go

Question 17

How many turns of the CAC to remove acetate groups?

Answer 17

3

Question 18

alpha ketoglutarate is similiar to ___ except it does not have kinase phosphase. It has all the other 3 catalytic enzymes.

Answer 18

PDH

Question 19

Alpha KG is converted to _____. During this process, ____ is removed. The removal is_____

Answer 19

Succinyl CoA; CO2, spontaneous

Question 20

______ converts succinyl CoA to succinate

Answer 20

succinyl CoA Synthase

Question 21

Succinyl CoA Synthase is also known as

Answer 21

Thiokinase

Question 22

What is used by thiokinase to break thioester bond?

Answer 22

inorganic phosphate

Question 23

Where is ATP made?

Answer 23

in the muscle

Question 24

Where is GTP made?

Answer 24

in the liver

Question 25

What converts succinate to fumarate?

Answer 25

succinate dehydrogenase (SDH)

Question 26

Succinate dehydrogenase is the only enzyme not in the matrix where is it embedded?specifically?

Answer 26

inner mitochondria membrane | Complex 2

Question 27

Succinate Dehyrogenase produces____ along with fumarate?

Answer 27

FADH2

Question 28

Fumarase uses ____ to replace double bond between carbons

Answer 28

water

Question 29

Fumarase

Answer 29

converts fumarate to malic acid

Question 30

What enzyme converts malic acid to oxaloacetate

Answer 30

malate dehydrogenase

Question 31

Which enzymes are the regulatory enzymes in the CAC?

Answer 31

citrate synthase isocitrate dehydrogenase alpha ketoglurate dehydrogenase

Question 32

What slows isocitrate dehydrogenase? (3)

Answer 32

ATP NADH citrate

Question 33

What slows alpha ketoglumarate dehydrogenase? (3)

Answer 33

ATP NADP succinyl CoA

Question 34

How many acetates go thru CAC?

Answer 34

2

Question 35

How many CO2, NADH, FADH, and ATP are produced total after citric acid cycle?

Answer 35

CO2=4 NADH=6 FADH2=2 ATP=2

Question 36

Both NADH and FADH2 produce______

Answer 36

ATP

Question 37

Oxaloacetate can also be converted into which amino acid?via?

Answer 37

aspartic acid | transamination

Question 38

The citrate produced creates what type of feedback on glycolysis?

Answer 38

negative feed back

Question 39

What does dehydrogenase involve?

Answer 39

removal of hydrogen

Question 40

Which molecules can be converted into amino acids

Answer 40

oxaloacetate | alpha ketoglutarate

Question 41

Citrate Synthase has a _____ delta G

Answer 41

negative

Question 42

Malate Dehydrogenase has a _____ delta G

Answer 42

positive; not favorable

Question 43

Since MDH has a positive delta G, what enzyme helps the reaction occur

Answer 43

Citrate Synthase