Exam 1 - Ch. 6/7

Question 1

free energy

Answer 1

amount of energy in a system that can be used to do work

Question 2

delta G

Answer 2

is negative: the rxn can be spontaneous, is exergonic, so energy yielding (react. higher than prod.)

is positive: the rxn needs energy, is endergonic, so energy requiring (prod. higher than react.)

Question 3

enzymes

Answer 3

proteins that act on substrate molecule and converts it to a different molecule

lowers the activation energy of the rxn

ends in -ase

Question 4

activation energy

Answer 4

the minimum amount of energy the reactants must have before they can give rise to products

Question 5

oxidoreductases

Answer 5

oxidation-reduction reactions

Question 6

transferases

Answer 6

transfer of functional groups from one molecule to another

Question 7

hydrolases

Answer 7

hydrolytic cleavage of one molecule into two molecules

Question 8

lyases

Answer 8

removal of a group from, or addition of a group to, a molecule

Question 9

isomerases

Answer 9

movement of a functional group within a molecule

Question 10

ligases

Answer 10

joining of two molecules to form a single molecule

Question 11

active site

Answer 11

a cluster of amino acids where the substrate binds and the catalytic event takes place

Question 12

coenzymes

Answer 12

non protein (vitamins) cofactors that are located in active site and are required for catalytic function

Question 13

substrate specificity

Answer 13

each enzymes only binds a specific substrate

Question 14

enzyme properties

Answer 14

1. sensitivity to temperature
   rate of rxn increases as temp increases until denature
2. sensitivity to pH
   active site amino acids are charged, so optimum pH needed

Question 15

inhibitors

Answer 15

inactivate proteins
reversible when a noncovalent bond
irreversible with permanent bond

Question 16

3 steps of enzyme function

Answer 16

1. Substrate binds
2. Substrate activated
3. Catalysis - substrate to product

Question 17

enzyme kinetics

Answer 17

concentrations of substrates, products, and inhibitors determines reaction rate

Question 18

Effects of [substrate]

Answer 18

increasing substrate increasing rate of rxn until ezymes are saturated

Question 19

How do inhibitors effect the rate of reaction

Answer 19

1. competitive - blocks binding of substrate (direct)

2. noncompetitive - changes protein’s shape (indirect)

Question 20

feedback inhibition

Answer 20

ability of the end product of a pathway to inhibit the activity of the first enzyme used in the pathway; ensures the pathway function is in tune with the concentration of the end product

Question 21

allosteric regulation

Answer 21

allosteric effector binds to the enzyme switching it to active

Question 22

covalent modification

Answer 22

binding of specific groups (phosphates, methyls, acetyl groups) to the enzyme affect its activity

Question 23

ribozymes

Answer 23

RNA molecules that have catalytic capabilities

Question 24

5 main functions of membranes

Answer 24

1. boundary & permeability barrier
2. organization & localization of function
3. transport processes
4. signal detection
5. cell-to-cell interactions

Question 25

membrane biochemical function

Answer 25

proteins are embedded in the membrane that can carry out chemical reactions

Question 26

fluid mosaic model

Answer 26

2 layers of phospholipids with proteins embedded
fluid - lipids
mosaic - proteins

Question 27

how does temperature affect fluidity

Answer 27

increase temp increases fluidity

Question 28

as carbon side chains increase, melting point

Answer 28

increases

Question 29

as carbon double bonds increase, melting point

Answer 29

decreases

Question 30

homeoviscous adaptation

Answer 30

maintain the same viscosity of the membrane despite changes in temperature

Question 31

integral proteins

Answer 31

embedded in the membrane

usually have hydrophobic and hydrophilic regions

Question 32

peripheral proteins

Answer 32

stay on the outside of the membrane
no hydrophobic region
bound via hydrogen bonds

Question 33

lipid-anchored proteins

Answer 33

attached to the membrane via lipids

Question 34

glycoproteins

Answer 34

proteins with a carbohydrate