Class 6: Oxidative phosphorylation

Question 1

what is the major source of one-carbon groups in the human

Answer 1

serine

Question 2

what is a process for the synthesis of ATP and the ,for source of ATP in aerobic organisms

Answer 2

oxidative phosphorylation

Question 3

source of ATP

Answer 3

high-energy electrons from NADH or FADH2 (from TCA cycle)

Question 4

path of OXPHOS

Answer 4

accomplished through a number of electron-transfer reactions, which take place in a set of membrane proteins known as the electron transport chain in the mitochondria

Question 5

results of OXPHOS

Answer 5

reduction of oxygen and the generation of a proton gradient (also called proton motive force), which is used to power the synthesis of ATP

Question 6

location of OXPHOS

Answer 6

mitochondria

Question 7

outer membrane of mitchondria

Answer 7

-permeable to most small ions and moleculesbc of Porin(allows passive diffusion

Question 8

inner membrane of mitochondria

Answer 8

• folded into ridges called cristae
• impermeable to most molecule
• the site of electron transport and ATP synthesis
• FA transport

Question 9

Intermembrane space of mitochondria

Answer 9

• nucleotide kinase
• proton gradient

Question 10

martix of mitochondria

Answer 10

the citric acid cycle and and fatty acid oxidation occur in the matrix
- could write more

Question 11

what takes place in the four large protein complexes embedded in the inner mitochondrial membrane

Answer 11

the oxidation-reduction reactions that allow the flow of electrons from NADH and FADH2 to oxygen. Also called the respiratory chain resulting in the reduction of oxygen and the generation of the proton gradient

Question 12

the electron carriers in the protein complexes include?

Answer 12

1) flavin mononucleotide (FMN)
2) iron associated with sulfur in proteins (iron-sulfur proteins),
3) a mobile electron carrier called coenzyme Q (Q).
4) iron incorporated into hemes that are embedded in cytochromes, mobile electron carrier proteins.

Question 13

ubiquinone

Answer 13

oxidized coenzyme in carrier 3

Question 14

ubiquinol

Answer 14

reduced coenzyme in carrier 3

Question 15

study slide 13-16

Answer 15

mmm

Question 16

Reactive Oxygen Species (ROS)

Answer 16

1) Electrons leak at Complex I and III from semiquinone radical

2) Partial reduction of O2 generates highly reactive oxygen derivatives, called reactive oxygen species (ROS).

3) ROS include superoxide ion (O2-), peroxide ion (O22-), and hydroxyl radical (OH).

4) 2%-4% of oxygen molecules consumed by mitochondria are converted into superoxide ions.

Question 17

ros and human disease slide 20

Answer 17

jjjj

Question 18

what enzymes protect against ROS damage

Answer 18

1) superoxide dismutase
2) Catalase
3) GSH peroxidase

Question 19

ROS

Answer 19

superoxide ion, peroxide ion, and hydroxyl radical

Question 20

Other defenses against ROS

Answer 20

vitamin E
vitamin C
vitamin A
exercise
-could write descriptions

Question 21

what is the proton motive force

Answer 21

The proton gradient generated by the oxidation of NADH and FADH2 is called the proton-motive force, which powers the synthesis of ATP.

Question 22

chemiosmosis hypothesis

Answer 22

electron transport and ATP synthesis are coupled by a proton gradient across the inner mitochondrial membrane.

Question 23

electrochemical gradient (proton gradient)

Answer 23

drives the formation of proton - motive force : a chemical gradient and a charge gradient.

Question 24

proton motive force formula

Answer 24

(Delat p) = chemical gradients + charge gradient

Question 25

F0 component of ATP synthase

Answer 25

The F0 component (hydrophobic) is embedded in the inner mitochondrial membrane and contains the proton channel

Question 26

F1 component of ATP synthase

Answer 26

The F1 component contains the catalytic activity and protrudes into the mitochondrial matrix.

Question 27

4 steps of proton flow around the c ring powering ATP synthesis

Answer 27

1) Subunit a, which abuts the c ring, has two channels that reach halfway into the a subunit. One half channel opens to the intermembrane space and the other to the matrix.
2) Protons enter the half channel facing the proton-rich intermembrane space, bind to an glutamate residue on one of the subunits of the c ring, and then leave the c subunit once they rotate around to face the matrix half channel.
3) The force of the proton gradient powers rotation of the c ring.
4) The rotation of the c ring powers the movement of the γ subunit, which in turn alters the conformation of the β subunits.

Question 28

ability of ASP and GLU side chains to accept protons can be important in ?

Answer 28

enzyme catalyst

Question 29

The three catalytic B subunits of the F1 component can exist in what 3 conformations

Answer 29

O (open) form: release
L (loose) form: trap
T (tight) formL synthesis

Question 30

how many protons must flow through the matrix for each molecule of ATP to be formed

Answer 30

3
- flow though each proton drives 1200degree rotation of B subunit

Question 31

the complete oxidation of glucose yields about how many molecules of ATP

Answer 31

30
-glycolysis: 2 ATP
-TCA cycle: 2 ATP
-OXPHOS: ~26

Question 32

the glycerol 3-phosphate shuttle

Answer 32

NADH –> FADH2
-in muscle, electrons from cytoplasmic NADH can enter the electron transport chain by using this shuttle
-after the electrons are transferred from NADH to FADH2 they’re subsequently to Q to form QH2

Question 33

the malate-aspartate shuttle

Answer 33

NADH –> NADH
-In heart and liver, electrons from cytoplasmic NADH are used to generate mitochondrial NADH in malate-aspartate shuttle.

The malate-aspartate shuttle consists of two membrane transporters and four enzymes.

Question 34

go over slides 34- end

Answer 34

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