Biology 288-Lecture 5

Cell Biology

If the change in free energy is less than 0, what happens to the entropy of the system?

The entropy of the system increases

What effect does an enzyme have on the free energy of a reaction?

An enzyme cannot change the free energy in any way

Every reaction has a reverse reaction, when does the reverse reaction stop proceeding?

The reverse reaction will proceed until the ration of concentrations \[X\]/\[Y\] is equal to k-the equilibrium constant

What happens if the concentrations of a reaction are not ideal?

It decreases the likelihood of any products being formed

What kind of reactions can be coupled?

Reactions that share 1 or more intermediate

What is the overall free energy change?

The sum of individual free energy values

How is an unfavorable reaction driven?

By coupling to a favorable reaction

Define hydrolysis

The breaking of covalent bonds using water

What byproduct is released by hydrolysis?

Energy

If the conversion of Y-X is an energetically favorable reaction, will the conversion of Y to X happen often?

Yes, because it does not require a high energy input

If the conversion of Y-X is an energetically favorable reaction, will the conversion of X to Y happen often?

No, this is the reverse of a favorable reaction and it will require a lot of energy

If the conversion of Y-X is an energetically favorable reaction, how will the reaction ever reach equilibrium?

X will convert to Y but not often and at a very slow rate. The conversion of Y to X will occur often and eventually we will accumulate a lot of X that it will compensate for the slow conversion of X to Y. Now X is being converted to Y at the same amount that Y is being converted to X, the reaction has reached equilibrium

What is another thing indicated by the equilibrium constant?

It indicates the strength of non-covalent binding interactions

What is the most widely used activated carrier?

ATP

What are the 5 complexes of the electron transport chain?

Complex 1,2,3,4 and cytochrome C

Where can the elctron chain be found?

In the mitochondria

What limits the production of ATP?

The oxygen levels in the blood

What happens to ATP levels when there is no sufficient oxygen in the blood?

The ATP levels decline

What role does creatine play in the conversion of ATP to ADP?

Creatine\~P donates a phosphate to ADP and converts it to ATP while losing its phosphate and becoming creatine

What kind of bonds hold together the phosphates in ATP?

Phosphoanhydride bonds

What are the two steps of harnessing ATP in order to join molecules together?

1. Activation: ATP transfers a phosphate to A-OH to produce a high energy intermediate

2. Condensation: The activated intermediate reacts with B-H to form the product A-B, a reaction accompanied by the release of an inorganic phosphate

What is the function of H+ gradients in ATP synthesis?

They allow the binding of a phosphate group to ATP

What kind of agent is NAD+?

Its an oxidizing agent

What kind of agent is is NADPH?

A reducing agent

What kind of reactions does NAD+ take part in?

Catabolic reactions

What kind of reactions does NADPH take part in?

Anabolic reactions

What can be done to breakdown polymers?

Their bonds can be hydrolyzed by the addition of water

How does insulin increase glucose levels?

Glucose is a polymer, insulin increases its concentration by removing water to allow glucose to bond

How does glucagon decrease glucose levels?

Glucagon adds water in order to break the bonds built by the glucose molecule