Biochemistry Video 20

Front 1

What are the two pathways that bring NADH into the mitochondria?

Back 1

Malate shuttle and the glycerol-Phosphate shuttle

Front 2

How does NADH get into the mitochondriavia the malate shuttle?........ glycerol-phosphate shuttle?

Back 2

To get in through the malate shuttle the NADH gives it H with electrons to oxaloacetate, which converts it to malate, which can easily cross the mitochondrial membrane through it’s shuttle, and then converts back to NADH………….. The glycerol phosphate shuttle converts the NADH to FADH2, which can go into the electron transport chain

Front 3

What part of the electron transport chain does NADH give it’s electrons to?

Back 3

Complex I, aka NADH dehydrogenase

Front 4

Where do the electrons go from NADH dehydrogenase?

Back 4

Coenzyme Q, aka obiquinone

Front 5

Where do the electrons go from coenzyme Q?

Back 5

Complex III, aka cytochrome B and C1

Front 6

Where do the electrons go from complex III, aka cytochrome B / C1?

Back 6

Cytochrome C

Front 7

Where do the electrons go from cytochrome C?

Back 7

Complex IV, aka cytochrome A/A3, aka cytochrome oxidase

Front 8

What is special about cytochrome oxidase?

Back 8

It’s heme groups contain copper instead of iron.

Front 9

Where do the electrons go after cytochrome oxidase?

Back 9

They are picked up by oxygen to produce H2O.

Front 10

What are the complexes responsible for transferring FADH2 electrons into the electron transport chain?

Back 10

Glycerol-Phosphate Shuttle (from cytoplasm)………..Succinate dehydrogenase, aka complex II………. Fatty Acyl CoA dehydrogenase

Front 11

Where do the electrons coming in from FADH2 go to?

Back 11

Directly to Coenzyme Q, aka ubiquinone, bypassing complex I

Front 12

What are the three “plugs” or proton pumps in the mitochondrial membrane?

Back 12

Complex I, III, and IV

Front 13

What do the proton pumps do?

Back 13

They pum H+ outside the mitochondria in order to duild up a concentration gradient of Hydrogen outside the mitochondria.

Front 14

Hoe does Hydrogen get back into the mitochondria?

Back 14

It goes through the F0 subunit of the ATP synthase enzyme.

Front 15

What are the subunits of ATP synthase and what do they do?

Back 15

F0 and F1. F0 is a channel for protons to reenter the mitochondria. F1 has ATP synthase activity and phosphorylase ADP to ATP. It gets it’s energy from the protons flowing down their gradient through the F0 subunit.

Front 16

On what side of the mitochondrial membrane is the ATP produced?

Back 16

It is produced on the mitochondrial side of the mitochondrial membrane

Front 17

How does the atp get out of the mitochondria after it is produced?

Back 17

It is exchanged for ADP through ATP/ADP translocase

Front 18

What happens in hypoxia?

Back 18

The electrons do not have a reciever, thus the electrons stop flowing and NADH accumulates, which shuts down the Krebs cycle. Therefore the proton gradient dissipates and there is no more ATP made.

Front 19

Which drugs inhibit Complex I, aka NADH dehydrogenase, of the ETC?

Back 19

Barbituates and Rotenone

Front 20

Which drugs inhibit Complex iV, aka cytochrome A/A3, aka cytochrome oxidase?

Back 20

Cyanide, Carbon Monoxide, and Azide

Front 21

What often causes cyanide toxicity?

Back 21

Nitroprusside administration and as a result of fires

Front 22

What often causes carbon monoxide poisoning?

Back 22

Use of space heaters in the winter.

Front 23

Which drug inhibits ATP synthase?

Back 23

Oligomycin

Front 24

What is the mechanism of oligomycin inhibition of ATP synthase?

Back 24

It blocks the flow of protons through the F0 subunit. Thus the concentration of protons in the cytoplasm increases. Once it increases to a certain level, the electron transport chain senses this and shuts down. Thus the electron chain is shut down and even though there is still a strong gradient there will be be ATP produced because the F0 subunit of the ATP synthase is blocked

Front 25

Which drugs are known as uncouplers?

Back 25

2,4 DNP and thermogenin (brown adipose) and high doses of salicylates

Front 26

How do uncouplers work?

Back 26

They are molecules that can combine with protons and are able to cross the mitochondrial membrane into the mitochondria, thus bringing the proton into the mitochondria and reducing the proton gradient

Front 27

What are the two effects of uncouplers?

Back 27

1. reduce ATP synthesis due to lack of proton gradient ………….2. increase the electron transport chain due to the lack of proton gradient

Front 28

How many ATP are produced by one NADH molecule? ... FADH2 molecule?

Back 28

NADH = 3 .... FADH2 = 2

Front 29

What is the difference between glycogen use in tliver and muscle?

Back 29

In the liver, the glycogen stored in not for the use of the liver. In the liver the glycogen stored is for the use of the red blood cells and the brain cells. In the muscles, all of the glycogen stored is for the use of the muscles only.

Front 30

What triggers glycogen gynthesis?

Back 30

As ATP build up and the ETC, Krebs cycle, and glycolysis slow down, GLUCOSE-6P builds up and this is what triggers glycogen synthesis

Front 31

What is the form of glucose used to package glucose as glycogen?

Back 31

UDP-glucose

Front 32

What is the rate limiting step of glycogen synthesis?

Back 32

The activation of glycogen synthase by glucose, locally, and insulin, globally

Front 33

What are the two enzymes involved in glycogen synthesis?

Back 33

Glycogen synthase and branching enzyme

Front 34

What are the steps in the synthesis of glycogen?

Back 34

Glucose to glucose 6-P to glucose 1-P to UDP-glucose via UTP. UDP glucose is then chained together by glycogen synthase and branching enzyme

Front 35

What are the two enzymes involved in the breakdown of glycogen?

Back 35

Glycogen phosphorylase and debranching enzyme

Front 36

What triggers the breakdown of glycogen?

Back 36

Glucogon triggers the breakdown in the liver……………epinephrine controls the breakdown in liver and muscle………….and AMP controls the breakdown in muscle

Front 37

After glycogen is broken down in the muscle what happens to it?

Back 37

It is converted to Glucose-1P by glycogen phosphorylase and debranchig enzyme, then it is converted by glucose -6P and then proceed to go through glycolysis

Front 38

Which enzyme in the liver convets glucose 6P to glucose?

Back 38

Glucose 6P phosphatase

Front 39

What happens to glycogen when it is broken down in the liver cell?

Back 39

It is converted to Glucose-1P, which is then converted by Glucose 6P, which is then converted back to glucose via Glucose 6 phosphatase

Front 40

What is the only clel that has glucose 6P phasphatase

Back 40

Liver cell

Front 41

What is G6PD

Back 41

It is Glucose 6 phosphatase deficiency

Front 42

What type of bonds does glycogen synthase make?

Back 42

Alpha 1,4 bonds

Front 43

What does the branching enxyme of glycogen synthesis do? .... How many glucose molecules from the end does branching enzyme break the bond?

Back 43

It breaks alpha 1,4 bonds about 6-8 glucose molecules from the end……….. after breaking off the end of the chain it goes back about 4 glucose molecules on the original chain and then makes an alpha 1,6 bond to create a branch.

Front 44

In summary what are the effects of branching enzyme

Back 44

It breaks an alpha 1,4 bonds, goes back a few glucoses and then makes an alpha 1,6 bond

Front 45

What happens after branching enzyme makes it’s branches?

Back 45

Glycogen synthase extends both branches

Front 46

What will glycogen phosphorylasae do?

Back 46

It will break alpha 1,4 bonds to release glucose 1-P until it encounter the first branch point

Front 47

What does debranching enzyme do?

Back 47

Debranching enzyme breaks the alpha 1,4 bond nearest the branch point and transfers the oligoglucoes unit to the end of another chain and then goes back and hydrolyses the alpha 1,6 bond releaseing a single slucose from the former branch

Front 48

What are the inhibitors of glycogen synthase in liver and muscle?

Back 48

Liver = glucagons and epinephrine …………..Muscle = epinephrine