Biology Unit 2: Oxidative Phosphorylation

What substance are all the complexes used in the Electron Transport Chain

Enzymes

2 parts of Oxidative phosphorylation

Electron Transport Chain and chemiosis

How many steps does electron transport chain take up in oxidative phosphorylation

5 steps

Step 1

Complex 1 oxidzes NADH, complex 2 oxdizes FADH2, NAD+ and FAD are reused in glycolysis, kreb cycle and pyruvate oxidation

How many Protons are moved in Step 1

4 protons

Step 2

NADH Oxidation leads to pumping of protons from matrix to the intermembrane space which goes agains concentration gradient

What else happens in Step 2

Electrons are recieved by complex 1 and 2 and given to carrier Ubiquinone

Step 3

UQH2 (Ubiquinol) transports electrons to protein complex 3, it also carries protons

Step 4

Electrons at complex

III get picked up by

cytochrome c (last

electron carrier)

What else happens in Step 4

4 more protons from the matrix to intermembrane space

Step 5

Cytochrome C carries electron to protein complx 4, the last one, electrons are attracted to oxygen and water forms

What else happens in step 5

2 more protons are pumped out from matrix to intermembrane space

Electronegativity involvement in electron transport chain

its arranged in terms of increasing electronegativity, these increasing electronegativities pull the electrons along the chain

Carriers arranged from highest to lowest EN

1. Ubiquinone

2. Cytochrome C

3. Oxygen

Why can more protons be relased into intermembrane space

Energy is released as electrons are pulled by stronger and stronger oxidzing complexes, this allows for more protons to be relased into intermembrane space

How many protons does one NADH pump

10

How many protons does one FADH2 pump

6

Step 6

Electron transport chain makes an electrochemical gradient, intermembrane space is more positive and matrix is negative, this gradient is how the cell transfers stored energy from NADH + and FADH2d

Step 7

Protons are pushed through complex 4 through the enzyme ATP synthase, it causes enzyme to spin and it bonds to ADP and Pi to form ATP

How many protons are need for one ATP

3-4

How much ATP can one NADH pump mean

2.5-3 ATP

How much ATP can one FADH2 pump mean

1.5-2 ATP

Concentration of NADH in mitochondria

There is a higher concentration of NADH inside the mitochondria than the outside

How does NADH enter the mitochondria?

Active transport

How does the method of transportation that NADH takes to enter mitochondria

As a result, NADH from glycolysis produces less ATP

when compared to those produced inside the

mitochondria

CO

Enzyme inhibitor for cytochrome C oxidase (complex 4)

Cyanide

also an enzyme inhibitor for cytochrome C oxidase (complex 4)