Bio Midterm 2

Front 1

Different forms of energy depends on what?

Back 1

The stability and complexity of the system in consideration.

Front 2

What is the second law of thermodynamics?

Back 2

Every time there is energy transfer or transformation, there is an increase in the overall entropy of the universe

Front 3

Describe free energy and entropy in an unstable system vs. stable system

Back 3

An unstable system has a low degree of entropy and a greater amount of free energy than a stable system.

Front 4

What is Gibb's free energy equation? What do the variables stand for?

Back 4

deltaG = deltaH - TdeltaS

G = Gibb's free energy
H = Total energy
T = Time
S = Entropy

Front 5

What's the relationship between positive/negative G value and energy in a reaction?

Back 5

A negative G value means the system gives up energy and is exergonic. A positive G value requires energy and is endergonic.

Front 6

What is the important chemical equation regarding glucose in metabolism?

Back 6

glucose + oxygen >> carbon dioxide and water

c6h12o6 + 6o2 >> 6co2 + 6h2o

Front 7

What are the components of ATP?

Back 7

A phosphate group, a ribose group, and an adenine group.

Front 8

Which bond is most important in ATP? What's an example?

Back 8

The third phosphate bond. An example is the synthesis of glutamine from glutamic acid and ammonia.

Front 9

What's the energy investment required to initiate a reaction?

Back 9

The activation energy

Front 10

What occurs immediately after a reaction begins?

Back 10

It enters the transition-state, which has higher energy than any other part of the reaction.

Front 11

What are enzymes?

Back 11

Enzymes are proteins that act as biological catalysts.

Front 12

What do catalysts do? What do they not do?

Back 12

Catalysts lower the required energy of activation. They do not cause reactions that could not ordinarily occur.

Front 13

What enzyme catalyzes RNA? What does it not do?

Back 13

RNA polymerase catalyzes formation of RNA but not DNA

Front 14

What hydrolyzes RNA polymers?

Back 14

The enzyme RNA nuclease

Front 15

What important enzyme is involved with phosphorylation, and what does it do?

Back 15

Hexokinase is an important kinase enzyme that accelerates the phosphorylation of a hexose monosaccharide like glucose.

Front 16

How do enzymes alter the activation state of a reaction?

Back 16

1. Orienting substrates
2. Add charges to substrates
3. Use covalent catalysis - temp. bond to substrate
4. Alter shape of substrates

Front 17

What conditions affect enzyme activity?

Back 17

1. Temperature and pH
2. Substrate concentration
3. Cofactors
4. Regulators and inhibitors

Front 18

What is allosteric regulation?

Back 18

An action at a site other than the active site.

Front 19

Discuss activators vs. inhibitors

Back 19

Activators stabilize enzymes to make reactions occur, inhibitors stabilize an inactive form. This is different from cooperativity!

Front 20

What is cooperativity?

Back 20

Cooperativity is an allosteric activation where a substrate stabilizes the active form of an enzyme. This is different from an activator!

Front 21

What are the two metabolic pathways, and what do they do?

Back 21

Anabolic pathways synthesize the building blocks of macromolecules.

Catabolic pathways break down macromolecules and fuel molecules.

Front 22

What was the first example of feedback inhibition in class?

Back 22

When isoleucine binds to an allosteric site on threonine deaminase

Front 23

How much energy is required to synthesize glucose from co2 and h2o?

Back 23

686kcal of energy per mol of glucose (180g)

Front 24

What are the main processes in glucose metabolism? Where is ATP generated?

Back 24

1. Glycolysis
2. Citric acid (or Krebs) cycle
3. Electron transfer chain & oxidative phosphorylation

ATP is generated by oxidative phosphorylation in the inner mitochondrial membrane

Front 25

What bond has the most potential energy and why?

Back 25

Covalent C-H bonds have the greatest potential energy because bonds are equidistant between C and H.

Front 26

Discuss reduction and oxidation

Back 26

A molecule that gains one or more electrons or hydrogen atoms is reduced. Oxidation is the other way around.

Front 27

Discuss reducing and oxidizing agents

Back 27

Reducing agents donate an electron or hydrogen atom.
Oxidizing agents accept an electron or hydrogen atom.

Front 28

Which agents do what in the metabolism of glucose?

Back 28

Glucose is the reducing agent (and is oxidized) while oxygen is the oxidizing agent is reduced).

Front 29

What's the deltaG of redox reactions?

Back 29

Redox reactions have a negative deltaG, so energy is removed to be used elsewhere.

Front 30

What are electron carriers? What's important about them?

Back 30

During the catabolism of glucose, electrons are transferred along a series of electron donors and acceptors called electron carriers. This produces energy in small packets.

Front 31

What are two key electron carriers involved in the breakdown of glucose?

Back 31

NAD and FAD

Front 32

What are the six steps in the release of energy from glucose?

Back 32

1. Transport glucose into cell
2. Glycolysis: glucose > 2 pyruvates
3. Pyruvate oxidation > acetyl coA
4. Citric acid / Krebs cycle
5. Electron transport chain
6. ATP synthase

Front 33

Where does glycolysis occur?

Back 33

In the cytoplasm.

Front 34

Where does the Krebs cycle occur?

Back 34

In the mitochondria.

Front 35

Where does the electron transfer chain occur?

Back 35

In the inner membrane of the mitochondria.