ʚ・electron transport

what do electron transport and oxidative phosphorylation pathways collectively accomplish?

They consist of a chain of enzymes and molecules that produce a high yield of ATP (metabolic energy).

Where do electron transport, oxidative phosphorylation, and the TCA cycle occur in eukaryotic cells?

in the mitochondria

Where are the electron transport and oxidative phosphorylation proteins located?

They are integral membrane proteins in the inner mitochondrial membrane

What is established during electron transport?

a proton gradient

What drives ATP synthesis during oxidative phosphorylation?

movement of protons through ATP synthase in the inner mitochondrial membrane.

What enzyme synthesizes ATP during oxidative phosphorylation?

ATP synthase

how are the TCA cycle and the electron transport/oxidative phosphorylation pathway linked?

They are linked by the protons and electrons carried by NADH and FADH₂, which deliver this energy to the electron transport chain

What are the roles of NADH and oxygen in electron transport?

NADH donates electrons to the chain, becoming NAD+; oxygen acts as the final electron acceptor

What is NAD⁺ and why is it important in mitochondria?

an electron carrier that cycles between NAD⁺ and NADH. It plays a central role in energy generation by carrying electrons and protons from the TCA cycle to the electron transport chain to help produce ATP

what are the components of NAD+

1. nicotinamide

2. ribose

3. adenine

4. second ribose that is part of adenosine

where are TCA enzyme located?

mitochondrial matrix

Where is the electron transport/oxidative phosphorylation located?

the inner mitochondrial membrane

What are the two mobile electron carriers in the electron transport chain?

coenzyme Q and cytochrome c

Which ETC complexes pump protons across the inner mitochondrial membrane?

Complexes I, III, and IV

What is the role of Coenzyme Q in the ETC?

carries electrons from complex I or II to complex III

What is the role of cytochrome c in the ETC?

Carries electrons from Complex III to Complex IV.

What is Complex I of the ETC?

NADH - coenzyme Q reductase

What is the function of Complex I of the ETC?

accepts electrons from NADH and passes them to Coenzyme Q

What is complex II of the ETC?

succinate — coenzyme Q reductase 

What is the function of Complex II of the ETC?

accepts electrons from FADH₂ (from the TCA cycle) and passes them to coenzyme Q

What is Complex III of the ETC?

coenzyme Q — cytochrome c reductase

What is the function of Complex III of the ETC?

transfers electrons from coenzyme Q to cytochrome c

What is Complex IV of the ETC?

cytochrome c oxidase 

What is the function of Complex IV of the ETC?

transfers electrons from cytochrome c to oxygen (the final electron acceptor), forming water

complex I is also known as?

flavoprotein 1

complex II is also known as?

flavoprotein 2

complex I contains what coenzyme?

flavin mononucleotide (FMN)

how many subunits are in complex I?

>30

complex II contains which coenzyme?

flavin adenine dinucleotide (FAD)

complex II is composed of how many subunits?

4

FMD and FAD are derívales of what?

Vitamin B2 (riboflavin)

what is ATP synthase?

a spinning molecular motor/enzyme that physically rotates and is responsible for giving us the most ATP

how fast does ATP synthase spin?

6,000 revolutions per minute / ~100 revolutions per second

what does the rotation in ATP synthase do?

it powers the enzyme to attach phosphate to ADP to create ATP

what does the F1 unit in ATP synthase do?

catalyzes ATP synthase

what does the F0 unit do?

forms a transmembrane pore or channel through which protons move to drive ATP synthase

what are the subunits and number of subunits in F1 spheres?

alpha — 3

beta — 3

gamma —1

delta — 1

epsilon — 1

what subunits and number of subunits are in the F0 integral membrane protein complex?

a — 1

b — 2

c — 10/13

what is the malate aspartate shuffle?

transfers NADH from the cytosine into the mitochondrial matrix

how does the malate aspartate shuffle work?

The NADH produced by glycolysis in the cytosol cannot pass through the inner mitochondrial membrane. Therefore, the H+ of NADH, and free H+, are linked to oxaloacetate in the cytosol to produce malate, which is readily transported into the mitochondrial matrix. H+ are then added back to NAD+ to regenerate NADH. This effectively transfers NADH from the cytosol into the matrix.