chapter 8⚡️

Question 1

the first law of thermodynamics

Answer 1

energy can be transferred and transformed but it cannot be created or destroyed

Question 2

the second law of thermodynamics

Answer 2

every energy transfer or transformation increases the entropy of the universe

ex. during energy transformation some energy is converted to thermal energy and released as heat

Question 3

metabolic pathway

Answer 3

a specific molecule is altered in a series of defined steps resulting in a certain product

each step is catalyzed by an enzyme(macromolecule that speeds up chemical reaction)

Question 4

metabolism

Answer 4

the totality of an organisms chemical reactions

Question 5

catabolic pathways

Answer 5

release energy by breaking down complex molecules to simpler compounds

Question 6

anabolic pathways

Answer 6

consume energy to build complicated molecules from simpler ones

Question 7

catabolic pathways do what and an ex of it

Answer 7

-release energy
-break down molecules
-require enzymes to catalyze the

ex.cellular respiration like breakdown of glucose

Question 8

anabolic pathways do what and an example

Answer 8

-consume energy
-build up larger molecules
-considered uphill
-requires enzymes to catalyze them

ex. photosynthesis

Question 9

exergonic reaction

Answer 9

proceeds with a net release of free energy and is spontaneous

G decreases and G is negative

Question 10

endergonic reaction

Answer 10

absorbs free energy from its surroundings and nonspontaneous

G increases and G is positive

Question 11

kinetic energy

Answer 11

energy associated with motion

Question 12

atp(adenosine triphosphate)

Answer 12

it is the cells energy shuttle

composed of ribose(a sugar)
adenine(a nitrogenous base) and three phosphate groups

Question 13

what does atp do in metabolism

Answer 13

it lowers cellular work by pairing exergonic reactions to endergonic reactions

Question 14

atp can be regenerated by what

Answer 14

the addition of phosphate to adp

Question 15

enzyme do what

Answer 15

speed up metabolic reactions by lowering energy barriers

Question 16

enzymes are

Answer 16

a macromolcule(protein) that speed up a reaction without being consumed by the reaction

biological catalysts that facilitate chemical reactions by lowering activation energy

Question 17

activation energy (EA)

Answer 17

the initial energy needed to break bonds of the reactants

Question 18

activation energy is supplied by what

Answer 18

heat in the form of thermal energy

thermal energy accelerates the reactant molecules so they collide more often

Question 19

when molecules absorb enough activation energy they are in an unstable condition called

Answer 19

transition state

Question 20

substrate

Answer 20

the reactant that an enzyme acts on

Question 21

enzyme-substrate complex

Answer 21

the enzyme binds to its substrate

while bound the catalytic activity of the enzyme converts substrate to product

Question 22

for an enzyme mediated chemical reaction to occur what must happen

Answer 22

the shape and charge of the substrate must be compatible with the active site

Question 23

active site

Answer 23

region of the enzyme where substrate binds( where catalysis occurs)

Question 24

active site is formed from

Answer 24

few of the enzymes amino acids and the rest of the protein molecule provides the framework that determines shape of active site

Question 25

the specificity of an enzyme is attributed to

Answer 25

a complementary fit between the shape of its active site and the shape of the substrate

Question 26

induced fit is when and it results from

Answer 26

the substrate enters the active site and the enzyme shape changes slightly, tightening around the substrate like a handshake

it results from interactions between chemical groups on the substrate and active site

Question 27

what does induced fit do

Answer 27

it brings chemical groups of the active site into positions that enhance catalysis of the reaction

Question 28

effects of temp on enzyme activity

Answer 28

reaction rate increases with increasing temp

at optimal temp enzyme catalyzes it’s reaction at the maximum possible rate

enzymes denature at temps beyond the optimal

Question 29

effects of substrate concentration on enzyme activity

Answer 29

increasing substrate concentration speeds up the rate of enzyme catalyzed reaction

any increase past optimal doesn’t change reaction(every enzyme is filled)

Question 30

effects of pH on enzyme activity

Answer 30

each enzyme has an optimal pH that is dependent on the environment where it’s active

Question 31

cofactor

Answer 31

no protein helpers for catalytic activity

Question 32

competitive inhibitor and how can it be overcome

Answer 32

mimics the substrate and competes for the active site

it reduces the productivity of enzymes by blocking substrates from entering active sites

it can be overcome by increasing the concentration of substrate

Question 33

non competitive inhibitors

Answer 33

binds to enzyme away from the active site

it alters the shape of the enzyme so that even though the substrate can still bind the active site functions less effectively

Question 34

allosteric regulation

Answer 34

when a regulatory molecule binds to a protein at one site and affects the proteins function at another site

this regulation can either inhibit or stimulate enzyme activity

Question 35

allosteric enzymes are made from

Answer 35

polypeptide subunits each with its own active site

Question 36

binding of activator vs inhibitor

Answer 36

activator- stabilizes the shape that has functional sites

inhibitor- stabilizes the inactive form of the enzyme

Question 37

feedback inhibition

Answer 37

the end product of a metabolic pathway shuts down the pathway

prevents a cell from wasting chemical resources by synthesizing more product than needed