MCB 2610: Exam 3 pt. 6

metabolism is the sum of all?

the chemical reactions in an organism, catabolic and anabolic

catabolism is the energy?

releasing processes

anabolism is the energy?

using processes

catabolism gives us?

ATP, simple molecules and electrons (usually make these to make larger macromolecules)

anabolism requires?

energy

simple molecules such as glucose, amino acids, glycerol and fatty acids use ATP immediately to?

bring order to the system

anabolic reactions transfer energy from?

ATP to complex molecules

catabolic reactions transfer energy from?

complex molecules to ATP

metabolic pathway

sequence of enzymatically catalyzed chemical reactions

metabolic pathways are determined by?

enzymes

enzymes are encoded by?

genes

1st law of thermodynamics

energy neither created nor destroyed but may be converted

example of 1st law of thermodynamics

potential to kinetic energy

1st law of thermodynamics where energy is neither created or destroyed means the amount of energy within the universe is?

stable

2nd law of thermodynamics

physical and chemical processes proceed in such a way that the randomness of the system increases

2nd law of thermodynamics - universe is always moving from?

an ordered system to a less ordered system

entropy

measure of randomness or disorder in a system

delta G

change in free energy

delta G tells us how much?

usable energy we have

endothermic

requires energy; non-spontaneous; +delta G, energy-absorping

exothermic

energy releasing; spontaneous, - delta G and occurs without input of ATP into a system

activation energy

required to bring molecules together in a specific way

reactant has to reach transition state before?

it's converted into a product

the greater the activation energy the more slowly a reaction will occur because?

it takes reactant longer to reach transition state

enzymes do what do activation energy?

lower it

enzymes speed up the rate ?

at which a reaction occurs

enzymes speeding up the rate of reaction is important because spontaneous reactions doesn't need input of ATP to make reaction run but if the reaction doesn't happen quickly enough it might not be?

biologically or physiologically relevant so you need an enzyme

energy to reach transition state usually comes from?

heat energy that is absorbed by reactants from the environment

when you add an enzyme to a system does it change the amount of free energy that is available during that reaction?

no

how do enzymes lower activation energy

by increasing concentrations of substrates at active site of enzyme and orienting substrates properly with respect to each other

by increasing concentrations of substrates of active site of enzyme it makes it more likely that?

enzyme comes into contact with substrate

every enzyme has a specific?

affinity for its substrate

enzymes pushes substrates together in the appropriate manner and with enough strength so?

bonds will break to allow us to reach transition state

two models for enzyme-substrate interaction

lock and key and induced fit

the turnover number is generally?

1-10,000 molecules per second

turnover number

max # of molecules of substrate that an enzyme can convert to pro catalytic site per unit time

majority of enzymes have one or more than one substrate it will interact with?

one

structure is important for function due to?

active site being incredibly specific to substrate

is an enzyme ever used up?

no

lock and key model does not allow for?

flexibility but we know that there is flexibility in an enzyme

induced fit model

as a substrate binds, enzyme shifts a little and hugs around it having flexibilty

enzymes are?

catalysts

some enzymes are composed solely of?

one of more polypeptides

some enzymes are composed of one or more polypeptides AND ?

non-protein components

cofactor = ?

coenzymes/prosthetic groups

a cofactor can be?

organic or inorganic

coenzymes are the __ components and are loosely attached to protein component

organic

prosthetic groups are the __ components and are firmly attached to the enzyme itself and are ions like magnesium

inorganic

if you're an enzyme that requires a cofactor and you don't have it will you function?

no

apoenzyme

protein portion - inactive

holoenzyme

apoenzyme + cofactor - active

important coenzymes

NAD+, NADP+, FAD, and Coenzyme A

coenzymes can act as?

carriers

enzymes can be denatured by?

temperature and pH

does temperature affects enzyme activity in the same way?

no high temp denatures protein while low temp lowers rate of molecule motion (substrate and enzyme don't come together)

does pH affect enzymes in the same way?

yes both acidic and alkaline denature enzyme

effect of concentration of substrate - as the concentration of a substrate increases the __ of final product formation increases

rate

after all enzyme molecules are saturated with substrate will there be a further increase?

no

what can you do to overcome flatline of rate?

add more enzymes

Km = ?

substrate concentration required by the enzyme to operate at half its maximum velocity

low Km = ?

high affinity

high Km = ?

low affinity

if you have a low affinity you need?

lots of substrate in the environment

enzymes with a high affinity for substrate are good at?

acquiring what is there even if there is low amount of substrate