Ox Phos Agbas

Question 1

Describe the ultrastructure of the mitochondria

Answer 1

oval shaped organelles with two membrane systems

Outer membrane is permeable to most small molecules due to porins (VDAC-voltage Dependent Anionic Channels)

Inner membrane is impermeable and has metabolite transporters

Two compartments

1. Intermembrane space
2. Matrix(TCA and faty acid oxidation)

Question 2

Where does ox phos occur?

Answer 2

In the inner membrane of the mitochondria

Question 3

Describe the history of the mitochondrial genome

Answer 3

Data has narrowed it down to one bacteria, Rickettsia prowazekii, from a single endosymbiotic event

Human mitochondrial DNA has 16569 bp and 13 respiratory chain proteins

maternally inherited

Question 4

What is the goal of Ox Phos?

Answer 4

1. Takes the NADH and the FADH2 from the TCA cycle and flows them through 4 complexes in order to reduce molecular O2 to water
2. proteins are pumped to the intermembrane space (proton gradient)
3. Return through the ATP synthase to make more ATP

Question 5

Describe Complex 1 of the ETC

Answer 5

NADH dehydrogenase or NADH-Q oxidoreductase

Large protein that is encoded by nuclear and mitochondrial genes

Has iron sulfur clusters throughout that help with the reduction reactions

FIRST point of entry for NADH

Question 6

Describe complex II

Answer 6

Succinate-Q reductase complex

connects TCA to Oxphos

FADH2 delivers its electrons here where they are transferred to Fe-S then to Q and then QH2

No proteins are pumped

leads to less ATP yielding

Question 7

Describe complex III

Answer 7

cytochrome c reductase

Takes the electrons from QH2 and then passes it to cytochrome c

2 protons are pumped across tot he cytoplasmic side

Question 8

Describe Complex IV

Answer 8

Cytochrome c oxidase

Last complex: transfers electrons from the reduced cytochrome c and delivers them to O2 to make water

makes the process aerobic and allows humans to breathe

4 electrons are used in order to reduce O2 to water

protons pumped to the matrix

Question 9

Define the respirasome.

Answer 9

Made up of complexes I, III, and IV.

Question 10

Describe coenzyme Q

Answer 10

Also known as ubiquinone

Transfers electrons from complex I and complex II to complex III

The enzyme has a series of 5C isoprene tails that make it hydrophobic

CoQ 10 is most common

Question 11

Describe cytochrome c

Answer 11

Electrons are taken from III to IV

final component

Catalyzes the reduction of O2

Question 12

Describe the flow of energy along the ETC

Answer 12

Starts at a high free energy (negative) and decreases (positive Eo) as it continues

Question 13

Describe free radicals in detail and tell what is affected if they are released (RNS and ROS)

Answer 13

Free radicals are the result of a partial reduction of O2 (superoxide ion (O2(-)) and peroxide (O2(2)))

Superoxide ion can lead to Arg oxidation which leads to the production of RNS and peroxide ion will lead to ROS

An OVERPRODUCTION of either of these will damage lipids, proteins, and DNA

Question 14

List a few BIG players in regards to free radical pathologies

Answer 14

1. Parkinsons

2. Diabetes

Question 15

Describe the defensive mechanisms that are in place within the body that help to control reactive oxygen species

Answer 15

Superoxide dismzutase (SOD) takes an oxygen radical and two protons and turns it into oxygen and hydrogen peroxide

Catalase takes hydrogen peroxide to oxygen and water

Question 16

Describe the various actions of superoxide dismutase

Answer 16

1. SOD1 contains a copper and zinc and is found in the cytoplasm
2. SOD2 has a maganese and Zinc, that is located in the mitorchondria

Question 17

Describe the different ways in which the body can get rid of ROS (in regards to gen chem)

Answer 17

ROS can be reduced to form hydrogen peroxide or oxidized to form O2

Question 18

Describe the prosthetic groups of NADH-Q oxidoreductase

Answer 18

There are two, Fe-S and FMN.

The electrons enter the chain through this enzyme and the transfer occurs via the FMN prosthetic group which leads to the formation of FMNH2

These electrons then travel to the Fe-S clusters in order to continue along the chain

Question 19

Describe the prosthetic groups of the succinate Q-reductase

Answer 19

There are two; FAD and Fe-S

The electrons from the citric acid cycle FADH2 are transferred to the Fe-S clusters (FAD is in there somewhere so just know its there)

Question 20

Describe the prosthetic groups that are present in the Q-cytochrome c oxidoreductase

Answer 20

There are 3 hemes
Heme BL- L stands for a low affinity and is closes to the cytoplasm
Heme BH- H stands for high affinity which is near the matrix side
Heme C1

And there are also Fe-S clusters

Question 21

Describe the prosthetic groups that are present with in the cytochrome c oxidase

Answer 21

Heme a: formyl group (instead of a methyl in the cyto c oxidoreductase), C17 replaces a vinyl group, and heme cannot be covalently attached