Biology Midterm 2

Front 1

Define Anabolic Reactions

Back 1

Link smaller molecules into bigger ones, energy storing reaction, require the input of energy

Front 2

Define Catabolic Reactions

Back 2

reactions which break large molecules down into smaller ones, release energy

Front 3

What is the first law of thermodynamics

Back 3

Energy is neither created nor destroyed, ie. Initial energy equals final energy.

Front 4

What is the second law of thermodynamics?

Back 4

(Entropy) When energy is transformed, disorder in the universe increases.

Front 5

What is total free energy?

Back 5

Potential disorder

Front 6

What are the two ways that a cell can drive a chemical reaction? And what do they need to sustain themselves?

Back 6

1) By creating disorder inside the cell (digesting a polymer)
2) With a chemical reaction that releases heat and creates disorder in the universe.
These reactions require a constant uptake of energy-rich molecules.

Front 7

What is the equation for total free energy?

Back 7

dG = dH-TdS

Front 8

What happens when dG is negative?

Back 8

Free energy is released

Front 9

What happens when dG is positive?

Back 9

Free energy is required

Front 10

What are the four types of reactions and their conditions (using the free energy equation)

Back 10

1) Exergonic, heat is released and S, (entropy or disorder) is increased
2) Heat is released but entropy decreases therefore the reaction is only spontaneous below a certain temperature
3) Heat kept in (H goes up) and entropy increases but it must still be above a certain temperature
4)Heat is kept in and entropy decreases. This is endergonic and will NOT be a spontaneous reaction.

Front 11

What kind of reactions are anabolic reactions?

Back 11

They are endergonic

Front 12

What is chemical equilibrium?

Back 12

When a reaction A to B and it's reverse, B to A are both taking place at the same rate.What

Front 13

What is ATP used for?

Back 13

It's used in cells to capture, transfer and store energy

Front 14

What is ATP made from?

Back 14

Adenine nitrogen molecule, Ribose sugar base, and multiple phosphate groups (namely 3)

Front 15

What is the reaction for ATP?

Back 15

ATP +H20 -> ADP + Pi(phosphate group) + free energy

Front 16

Why is the reaction for ATP exergonic?

Back 16

Because the P-O bond breaking releases more energy than the H-O bond that forms after

Front 17

How is ADP removed?

Back 17

Either by hydrolysis or reforming to ATP

Front 18

What is activation energy?

Back 18

Energy required to push to exergonic reactions along (put it into some kind of transition state)

Front 19

What is a catalyst?

Back 19

A substance that speeds up a reaction but does not actually get used up in the reaction

Front 20

What are most catalysts made of? (biological catalysts)

Back 20

proteins, ie enzymes

Front 21

Does free energy change with catalysts?

Back 21

No, only the transformation or activation energy

Front 22

How are exergonic reactions initiated?

Back 22

By heat, to increase the average kinetic energy of molecules.

Front 23

How do enzymes work?

Back 23

Lower the activation energy

Front 24

What are the three ways that enzymes catalyze reactions?

Back 24

They orient the substrates correctly, they induce strain on the substrates, or they add charges to the substrates

Front 25

What are cofactors?

Back 25

These are usually metal ions or small organic molecules that help the enzymes induce a reaction

Front 26

What are the principles that govern metabolic pathways?

Back 26

- Each reaction in the pathway is catalyzed by it's own enzyme
- The operation of each metabolic pathway can be regulated by it's key enzyme

Front 27

What regulates metabolism?

Back 27

Inhibitors on enzymes

Front 28

What happens with irreversible inhibition?

Back 28

This doesn't allow the enzyme to ever react with the substrate again

Front 29

How does DIPF (mustard gas) irreversibly inhibit acetylcholinesterase?

Back 29

It covalently bonds to the active site

Front 30

What is a competitive inhibitor?

Back 30

An inhibitor that competes with the substrate for the active site

Front 31

What is a non competitive inhibitor?

Back 31

This is an inhibitor that doesn't compete for the active site but instead manages to change the enzyme so that it doesn't accept the substrate

Front 32

What is another name fore noncompetitive inhibitor?

Back 32

A Negative allosteric regulator

Front 33

What is more efficient? Allosteric or competitive inhibition?

Back 33

Allosteric, it doesn't need to compete with the substrate and is less likely to harm the active site.

Front 34

What do positive allosteric regulators do?

Back 34

They activate the enzyme

Front 35

Describe cooperative allosteric transition. Also, what is the general trend in the rate of allosteric transition with the number of subunits?

Back 35

Allosteric transition, first has a difficult time binding the inhibitor to the active site, but then this stabilizes the next subunit and so on. With more subunits.the enzyme activation becomes faster.

Front 36

What metabolic processes are used to breakdown glucose for energy?

Back 36

- Glycolysis followed by cellular respiration
- Glycolysis followed by fermentation

Front 37

Define reduction

Back 37

When hydrogen atoms or electrons are gained

Front 38

Define oxydation

Back 38

When electrons or hydrogen atoms are lost

Front 39

How do you recognize oxydation reactions?

Back 39

Usually in organic molecules, the number of C-H bonds decreases

Front 40

What is NAD?

Back 40

It carries the electrons in cellular redox reactions

Front 41

What is the reaction for NADH oxidation?

Back 41

NADH + H+ +1/2O2 -> NAD+ +H20 (0verall)
Oxidation: NADH -> NAD+ +H+ +2e
Reduction: 1/2O2 +2H+ + 2e -> H2O

Front 42

What is redox potential

Back 42

The tendency to lose or gain electrons

Front 43

What are the two stages of glycolysis?

Back 43

- ATP breaking a sugar to two C3
- Oxidation of a C3 giving NADH + H+ and ATP

Front 44

What is produced for every glucose in glycolysis?

Back 44

2 pyruvate
2 NADH + 2H
2 ATP

Front 45

How do you drive an unfavorable reaction?

Back 45

Couple them with a favorable one like hydrolysis of ATP

Front 46

What is the sugar broken down into before entering the second stage of glycolysis?

Back 46

Glyceraldehyde 3-phosphate

Front 47

What does the pyruvate after glycolysis do? Where is this reaction catalyzed?

Back 47

It's oxidixed to acetate and converted to acetyl CoA. Catalyzed in the mitochondrial matrix.

Front 48

Where does glycolysis take place?

Back 48

The cytoplasm

Front 49

Write out the glycolysis reaction.

Back 49

in notes

Front 50

Write out the equation for the oxydation of pyruvate

Back 50

in notes