oxidative phosphorylation and lipid metabolism transport

What is the chemiosmotic theory?

1. The proton concentration gradient is the energy reservoir that drives ATP formation

2. as electrons pass through the ETC, protons get pumped into the intermembrane space. This generates the proton motive force (PMF)

3. protons move back across the intermembrane space through ATP synthase

How does the proton gradient generated by the ETC drive ATP synthesis?

It serves as an energy reservoir due to differences in H+ concentration

How does the gamma subunit interact with the beta subunits to drive ATP synthesis?

every rotation causes conformational changes in the beta subunits which drives ATP synthesis

Why is it advantageous for there to be three active sites for driving ATP synthesis?

Each subunit has the ability to control ADP binding. This controls the rate of ATP synthesis

How does ATP get out of the matrix?

By an ADP-ATP translocator

What is uncoupling?

The process of releasing H+ back to the matrix without making ATP. Stimulates O2 consumption, therefore, heat is created

Hibernating animals and newborn babies have brown fat. What is this tissue used for, and what does it have to do with uncoupling?

mitochondria rich fat, used as energy storage during hibernation, has a natural uncoupling mechanism that allows for ATP synthesis

why are fats a better source of energy storage than carbohydrates?

They yield more energy and are more compact in storage

Under certain conditions, fatty acids are released from adipose tissue. What are these conditions?

When other sources are not available (?)

How does the fat releasing process work, and how is it controlled?

1. epinephrine and glucagon are released into the blood when glucose conc and insulin conc are low

2. They bind to receptors on the surface of adipocytes

3. when bound, adipocytes activate TAG metabolism

How are fats from our diet transported to other tissues?

1. exported into the blood by transporter proteins or diffusion

2. serum albumin binds to the fatty acids

3. FAs transported to where they are needed

Why is LDL “bad” cholesterol?

It can lead to buildups in your arteries

they mostly contain cholesterol and cholesteryl esters

Why is HDL “good” cholesterol?

They get rid of LDL

They decrease plasma cholesterol

How does ADP get into the matrix?

by an ADP-ATP translocator

How does Pi get into the matrix?

by a phosphate carrier symporter