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Flashcards in Oxidative Phosphorylation Deck (36)
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1

From one glucose molecule, the reactions of glycolysis, pyruvate dehydrogenase complex, and the TCA cycle produce

__ NADH + 10 H+
__ FADH2

Each one of them carries __ high-energy electrons

10 NADH + 10 H+
2 FADH2

two

2

essence of oxidative phosphorylation

1. Electrons from NADH and FADH2 are used to reduce___ to ___
2. Their energy is used to pump ___ from the mitochondrial ___ to the________ space
3. __ decreases in______ space, increases in the ___
4. _____ flow back across the membrane, following their concentration gradient
5. Energy of __ flow is used to phosphorylate __ to ____

1. Electrons from NADH and FADH2 are used to reduce O2 to H2O
2. Their energy is used to pump protons (H+) from the mitochondrial matrix to the intermembrane space
3. pH decreases in intermembrane space, increases in the matrix
4. Protons flow back across the membrane, following their concentration gradient
5. Energy of proton flow is used to phosphorylate ADP to ATP

3

- During glycolysis, __ NADH are formed in the cytoplasm
- NADH cannot cross the ____ _____ _____
- It cannot be re-oxidised to NAD+ directly using the electron transport chain
- The _____-_-_____ and ____-______ shuttles overcome this problem

- During glycolysis, 2 NADH are formed in the cytoplasm
- NADH cannot cross the inner mitochondrial membrane
- It cannot be re-oxidised to NAD+ directly using the electron transport chain
- The glycerol-3-phosphate and malate-aspartate shuttles overcome this problem

4

how the glycerol-3-phosphate and malate-aspartate shuttle works:

1. NADH from glycolysis is used to generate ____ from _____ in cytosol

2. ___ transporters transfer ____ to mitochondrial ____.

3. ____ conversion to
_____ in TCA cycle
generates ____ in addition to the malate that arises from Fumarate

so at the step where malate is converted to oxalacetate in the TCA cycle there is increased yield of NADH at this step as there is glycolytic yield and TCA yield


1. NADH from glycolysis is used to generate malate from oxaloacetate in cytosol

2. malate transporters transfer malate to mitochondrial matrix.

3. malate conversion to
oxaloacetate in TCA cycle
generates NADH in addition to the malate that arises from Fumarate


IF YOU ARE STUCK _ LOOOK AT THE SLIDE, you understood it last time

5

In oxidative phosphorylation, the electron transfer potential of NADH+ and FADH2 is converted into the _____ ___ ____ of ___

Phosphoryl transfer potential can be measured by the ____ _____ change, ___, for the _____ of ATP

Electron transfer potential is measured by the-____ _____ (or reduction potential),___, of a compound

In oxidative phosphorylation, the electron transfer potential of NADH+ and FADH2 is converted into the phosphoryl transfer potential of ATP

Phosphoryl transfer potential can be measured by the free energy change, ΔGo’, for the hydrolysis of ATP

Electron transfer potential is measured by the redox potential (or reduction potential), E’o, of a compound

6

- The standard redox potential E’o of a (reduced) substance X is a measure for how readily X donates an electron (in comparison with H2)
X- → X + e-
- A negative E’o means that the reduced form of X has a _____ affinity for electrons than __, a positive E’o means the opposite
- The standard free energy change is proportional to the change in _____ ____ ____ and the number of ____ transferred

The standard redox potential E’o of a (reduced) substance X is a measure for how readily X donates an electron (in comparison with H2)
X- → X + e-
A negative E’o means that the reduced form of X has a lower affinity for electrons than H2, a positive E’o means the opposite
The standard free energy change is proportional to the change in standard redox potential and the number of electrons transferred

7

in oxidative phosphorylation one of the first steps is the reduction f O2 to H2O, what allows the electron to be carried from the NADH (itself being oxidised to NAD+)

the fact that the redox potential for NAD+/NADH is lower than that for 1/2 O2/H2O

8

The standard free energy change for the reaction
½ O2 + NADH + H+ → H2O + NAD+
is ΔGo’ = - 220.1 kJ/mol
The standard free energy change for the _____ of ATP is ΔGo’ = - 31.4 kJ/mol

hydrolysis

9

what is oxidative phosphorylation the coupling of?

coupling of respiration to ATP synthesis

10

oxidative phosphorylation consists of two stages, what are they

1. electron transport
2. ATP synthesis

11

first stage of OP
1. electron transport
- electrons flow from NADH and FADH2 to O2
- respiratory chain
- energy is used to pump __out of the mitochondrial ____

electron transport
electrons flow from NADH and FADH2 to O2
respiratory chain
energy is used to pump H+ out of the mitochondrial matrix

12

second stage of OP
2. ATP synthesis
- _____ ____ of H+ across mitochondrial inner membrane
- energy stored in this _____can be used to synthesise ___

ATP synthesis
electrochemical gradient of H+ across mitochondrial inner membrane
energy stored in this gradient can be used to synthesise ATP

13

Electron transport and ATP synthesis are catalysed by ____ ____ ___

Electron transport and ATP synthesis are catalysed by separate proton pumps

14

the electron transport part (respiratory chain) uses ___ multiunit complexes in the ___ ____ ___

4, inner mitochondrial membrane

15

Electrons from NADH enter at complex __
Electrons from FADH2 enter at complex __

Electrons from NADH enter at complex I
Electrons from FADH2 enter at complex II

16

complex __ is part of the TCA cycle

II

17

Electrons are handed down from ___ to ___ redox potentials

Electrons are handed down from higher to lower redox potentials

18

THE 4 COMPLEXES are involved in the process meaning ____ are ultimately transferred from ___ onto O2 to form H2O

Electrons are ultimately transferred from NADH and FADH2 onto O2 to form H2O

19

what are the 4 complexes
I-
II-
III-
IV-

what are the 4 complexes
I - NADH- Q oxidoreductase
II- succinate -Q- reductase
III - Q-cytochrome C oxidoreductase
IV- cytochrome C oxidase

20

what does coenzyme Q do?

it is a stable protein that is involved in transporting the electron - it is a portable protein

21

what are the two accessory parts in the respiratory chain

coenzyme Q and cytochrome C

22

what are cytochromes?

Cytochromes are proteins which contain a haem group as a functional co-factor
Haem contains an Fe(II) ion which can take up and release electrons

23

how many H+ ions are pumped by complex 1, III and IV per NADH and H+ molecule

I- 4 are pumped
III- pumps 4
IV - pumps 2

ten in total

24

how many electrons are transferred by 1 nadh and H+

2e- this makes sense betcause 2 e are required to reduce half O2 to H2O

25

how do protons flow back through from intermembrane space to the matrix

ATP synthase

26

what are the three components of ATP synthase?

1. pore for protons
2. i§ntermembrane domain (F0)
3. matrix soluble domain known as F1

27

atp synthase
a, b, α, β, and δ subunits form _____

stator

28

c, γ, and ε subunits form ___-

rotos

29

Electron transport chain can be inhibited at many stages
- ____ , ____ and ____ inhibit transfer of electrons to O2

cyanide, azide, and CO

30

what is the P/O ratio

Number of molecules of inorganic phosphate (Pi) incorporate into ATP per atom of oxygen used