Chapter 3

Question 1

how to organisms create disorder to maintain order?

Answer 1

living organisms carry out never-ending stream of chemical reactions

Question 2

sum of these reactions are called what?

Answer 2

metabolism

• anabolic (building up)
• catabolic (breaking down)

Question 3

biosynthesis?

Answer 3

an enzyme-catalyzed process in cells of organisms in which substrates are converted to more complex products.

Question 4

how are chemical reactions organized?

Answer 4

pathways

Question 5

what happens in a chem reactions?

Answer 5

reactant (substrate) changed into a product

Question 6

how are chemical reactions in cells catalyzed?

Answer 6

enzymes (biological catalysts), allows them to be highly regulated

Question 7

what is the fundamental tasks of proteins?

Answer 7

act as enzymes- catalysts that increase rate of reaction in cells

Question 8

what also catalyzes reactions?

Answer 8

RNAs, but most reactions are catalyzed by proteins

Question 9

what happens in absence of enzymatic catalysis?

Answer 9

reactions would be slow that they would not occur under mild temp and pressure that are compatible with life

Question 10

two fundamental properties of enzymes?

Answer 10

1) increase rate of reactions without themselves being consumed or permanently altered by reaction.
2) increase rates without alt the chem equil between reactants and products

Question 11

what determines the equil between S and P

Answer 11

laws of thermodynamics

Question 12

2nd Law of T

Answer 12

universal tendency of things to become disordered

Question 13

what type of system would spont. change toward disorder

Answer 13

isolated system

Question 14

1st Law of T

Answer 14

energy can be transferred/transformed to one form to another. can’t be created or distroyed

Question 15

how are effects of enzyme on reaction illustrated?

Answer 15

energy change that occurs during the conversion from S to P

Question 16

how is the equilibrium of a reaction determined?

Answer 16

by the final energy state of S & P, which are unaffected by enzymatic catalysis

Question 17

what causes a reaction to proceed?

Answer 17

substrate must be converted to a high energy state called transition state

Question 18

what is the energy required to reach transition state?

Answer 18

activation energy- acts as barrier to progress reaction, limiting rate of reaction

Question 19

what do enzymes do to activation energy?

Answer 19

they reduce activation energy, increasing rate of reaction.

Question 20

what is an enzyme-substrate complex (ES)?

Answer 20

a catalytic activity of enzymes that involves the binding of their substrate to form ES

Question 21

where does the substrate bind to on a enzyme?

Answer 21

active site

Question 22

what happens when S is bounded to active site?

Answer 22

the S is converted into P of reaction, then released from the ezyme

Question 23

how does the substrate initially bind to active site?

Answer 23

by noncovalent interactions (h-bonds, i-bonds, hydrophobic interactions)

Question 24

another way enzymes speed up reactions?

Answer 24

altering the conformation of thier substrate

Question 25

Lock and key model

Answer 25

S fits precisely into active site

Question 26

induced fit

Answer 26

config of both enzyme and S are modified by S binding

Question 27

reaction intermediate?

Answer 27

amino acid side chain in active site react with S and form bonds with reaction intermediates

Question 28

How are enzymes regulated?

Answer 28

are modulated- regulated so that they function appropriately to meet needs of the life of a cell

Question 29

what is feedback inhibition?

Answer 29

product of a metabolic pathway inhibits the activity of enzyme involved in its synthesis

Question 30

what is allosteric regulation?

Answer 30

enzyme activity is controlled the binding of a small molecule to regulatory site

Question 31

what does binding of a regulatory molecule do to the enzyme?

Answer 31

changes conformation of enzyme, which alters shape of active site and catalytic activity of the enzyme

Question 32

what do covalent modifications do to enzyme activity?

Answer 32

regulates interaction with other proteins by adding phosphate groups.

Question 33

what is phosphorylation?

Answer 33

mechanism for regulatory enzyme activity.

Question 34

what does the addition of a phosphate group do to an enzyme?

Answer 34

either activates or inhibits the activities of many different enzymes

Question 35

what can selectively decrease the activity of certain enzymes?

Answer 35

enzyme inhibitors

Question 36

competitive inhibitors

Answer 36

chem looks like the S and competes to bind to active site

Question 37

noncompetitive inhibitors

Answer 37

binds to another spot of enzyme (not AS) and alters shape of enzyme, preventing binding to S

Question 38

spont. reactions

Answer 38

energetically favorable. reactants more energy than products. negative delta G

Question 39

how is energy affected by spont. reactions? disorder?

Answer 39

energy released by reaction. disorder increases in system

Question 40

nonspont. reactions

Answer 40

energetically unfavorable. reactants less energy than products. + delta G

Question 41

how is energy affected by nonspont. reactions? disorder?

Answer 41

energy is absorbed by reaction. disorder decreases

Question 42

how are chem reactions coupled?

Answer 42

using high energy intermediates called activated carrier molecules.

Question 43

what is the most important and most versatile of the activated carrier molecules releasing energy in cells?

Answer 43

ATP

Question 44

how is ATP broken down to ADP and Pi?

Answer 44

through hydrolysis reaction (favorable reaction)

Question 45

how is APT synthesized (ADP+Pi)?

Answer 45

condensation reaction (unfavorable)

Question 46

condensation?

Answer 46

joining two molecules by a covalent bond with the release of water

Question 47

what is the energy from ATP hydrolysis used for?

Answer 47

to drive condensation reactions for the synthesis of polysaccharides, proteins, and nucleic acids.