Bio Lecture 16 Electron Transport chain and ATP Synthase

What are complexes?

Complexes are multi-subunit protein structures within the electron transport chain that facilitate the transfer of electrons and protons across the inner mitochondrial membrane.

What is Ubiquinone?

Lipid-soluble molecule that transports electrons between Complexes I and II to Complex III in the electron transport chain, playing a vital role in cellular respiration.

Where is the electron transport chain?

Matrix of the mitochondria

What complex grabs electrons from NADH?

Complex I

What complex grabs electrons from FADH?

Complex II

What happens to protons?

Protons are pumped from the mitochondrial matrix into the intermembrane space, creating a proton gradient that drives ATP synthesis. Left behindin the matrix.

Where do the electrons end up?

Electrons are transferred to oxygen, forming water.

As the electrons move through the electron transport chain what happens to the energy?

The energy is gradually released and used to pump protons across the inner mitochondrial membrane to create a proton gradient for ATP synthesis.

What powers the electron transport chain?

The oxidation of NADH and FADH2 provides the energy needed to drive the electron transport chain.

What has the highest affinity for electrons?

Oxygen because it is the most electronegative.

What happens when a protein gets an electron?

Changes shape.

What is the purpose of the electron transport chain?

Pumping protons, pumping positive hydrogens from matrix and pumping them into the intermembrane space to create a proton gradient.

What are the pumps in the electron transport chain?

Complex 1, 3, and 4

What are the transfers in the electron transport chain?

Complex 2, Coenzyme Q, and Cytochrome c

Where is the high concentration of protons?

Intermembrane space of the mitochondria.

What happens inside complex 1?

NADH is oxidized, transferring electrons to the electron transport chain and pumping protons into the intermembrane space.

What is happening in Ubiquinone?

Receives electrons from complex I and II and transfers them to complex III while also helping to pump protons into the intermembrane space.

What is happening in-between complex 1 and Ubiquinone?

Electrons are transferred from complex I to Ubiquinone, facilitating its reduction while protons are pumped into the intermembrane space and there is an electrical current.

What are the four spaces in the electron transport chain?

Cytoplasm, outer mitochondrial membrane, intermembrane space, and inner mitochondrial membrane.

What is the purpose of ATP Synthase?

To synthesize ATP from ADP and inorganic phosphate using the proton gradient established by the electron transport chain.

What are the two subunits in ATP synthase?

F0 and F1

What is in ATP synthase?

channel to allow protons back into matrix which will spin the rotor and drive ATP synthesis. Mechanical/kinetic energy.

What is F0?

Located in the inner mitochondrial membrane and functions as a proton channel. It allows protons to flow into the mitochondrial matrix, spinning.

What is F1?

Located in the mitochondrial matrix, it is the catalytic site where ATP synthesis occurs. It is driven by the rotation of the F0 subunit as protons move through, stationary.

What goes into the ATP Synthase?

ADP and 3 phosphates

What comes out of ATP synthase?

ATP

How many ATP’s come out of one full twist?

Three

When pushing on enzymes and grabing substrates, what happens?

Products are made.

What are the 3 sites?

• Opening and binding to ATP

• Closing down tight and creating phosphate bonds

• Releasing the main ATP

First step of z-scheme?

Photosystem 2 absorbs light energy exciting electrons

Second step of z-scheme

electrons are transferred through carriers and H2O molecules are split

Third step of z-scheme

Electrons move through the electron transport chain

Fourth step of z-scheme

Photosystem 1 absorbs light energy exciting electrons, then transferred to ferredoxin

Fifth step of z-scheme

Electrons are transferred to NADP+ reducing it to NADPH

First step of cyclic transport

Light energy is absorbed by photosystem 1, exciting electrons

Second step of cyclic transport

Excited electrons are transferred to electron acceptor

Third step of cyclic transport

Electron travels through electron transport chainto generate a proton gradient across the thylakoid membrane.

Fourth step of cyclic transport

Protons pumped into thylakoid lumen

Fifth step of cyclic transport

Electron returns to photosystem 1, completing the cycle

Sixth step of cyclic transport

Electrons do not take the pathway to NADP+ so NADPH is not produced