bio 2180 chapter 6

for exam

all cells use energy in the form of....

adenosine triphosphate (ATP)

what is ATP composed of?

tri-phosphate groups, ribose, and adenine

phototrophs

organisms that capture energy from sunlight (ex: plants)

chemotrophs

organisms that derive their energy directly from chemical compounds (ex: animals)

autotrophs

make their own organic carbon using inorganic carbon as starting material (ex: plants)

heterotrophs

rely on other organisms for their organic forms of carbon (ex: animals)

metabolism

-all chemical reactions occurring in a cell/organism

- \= anabolism + catabolism

what are calories?

a measure of potential energy

two branches of metabolism

catabolism and anabolism

catabolism

set of chemical reactions that break down molecules into smaller units

-LOWER enthalpy & HIGHER entropy

anabolism

set of chemical reactions that build molecules from smaller units and REQUIRES INPUT OF ENERGY, usually in the form ATP

energy

capacity to do work

two forms of energy?

kinetic and potential energy

kinetic energy

Energy of motion

potential energy

stored energy that depends on object's structure and position

chemical energy

form of potential energy held in the chemical bonds between pairs of atoms in a molecule

chemical energy is a form of what type of energy?

potential energy

where is potential energy held in atoms?

in chemical bonds between pairs of atoms in a molecule

the more stable configuration has higher or lower potential energy?

lower potential energy

strong bonds contain \____________ chemical energy

not very much

weak bonds contain \_____________ chemical energy

a lot of

why do strong bonds have low chemical energy?

they already have a very stable arrangement so they don't need a lot of chemical energy to keep them together

ATP as cellular energy

ATP is a readily accessible form of energy for the cell

ATP acts as.....

an intermediary between fuel molecules that store a large amount of potential energy in their bonds and the activities of the cell that require the input of the energy

ATP is composed of?

adenosine (base adenine, 5 carbon sugar ribose, & triphosphate or 3 phosphate groups)

ATP's chemical relatives?

ADP & AMP

the chemical energy of ATP is held in?

the bonds connecting the phosphate groups (which are negatively charged and repel each other)

how is energy in the bonds connecting the phosphate groups of ATP used?

the energy is released when new stable bonds are formed that contain less chemical energy; the released energy can be harnessed to power the work of the cell

first law of thermodynamics

law of conservation of energy; the universe contains a constant amount of energy; energy is neither created or destroyed; new energy is formed and every is NEVER lost; energy changes from one form to another

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

How can the total energy remain the same, but the energy available to do work decrease?

some of the energy is available and some of it is not available to do work

as entropy increases....

so does the number of positions and motions available to the molecule

thermal energy

type of kinetic energy corresponding to the random motion of molecules and results in a given temperature

catabolic reactions result in....

increase of entropy (single ordered biomolecules broken down into several smaller ones)

anabolic reactions result in...

decrease of entropy (because they use individual building blocks to synthesize more ordered biomolecules)

production of heat....

increases entropy (random movement of molecules)

for a cell to function it requires what?

a CONSTANT input of energy

chemical reactions occur when...

molecules interact

what happens during a chemical reaction?

atoms keep their identity but bonds linking the atoms change

true or false: most chemical reactions are readily reversible

TRUE

The reversibility of the reaction is indicated by....

a double arrow

a forward reaction proceeds from

left to right (reactants on left side)

a reverse reaction proceeds from

right to left (reactants on right side)

increasing the concentration of the reactants favors the....

forward reaction

decreasing the products of a reaction favors the...

forward reaction

the laws of thermodynamics determine what?

whether a chemical reaction requires or releases energy available to do work

Gibbs Free Energy (G)

amount of energy available to do work

how to find delta G?

free energy of product - free energy of reactants \= ∆G

if the products of a reaction have MORE free energy than the reactants then...

* ∆G is POSITIVE
* -a net input of energy is required to drive the reaction forward

if the products of a reaction have LESS free energy than the reactants then...

\-∆G is NEGATIVE \n -energy is released and available to do work

exergonic reactions

\-negative ∆G \n -release energy \n -proceed spontaneously

enthalpy

total amount of energy

endergonic reactions

\-positive ∆G

require energy

not spontaneous

enthalpy (H)

total amount of energy

Gibbs free energy (G)

energy available to do work

entropy (S)

degree of disorder

can ∆S (entropy) ever be 0?

NO, there is always disorder in the universe

less disorder \=

negative ∆S

more disorder \=

positive ∆S

absolute temp (T)

measured in degrees calvin

total amount of energy (H) \=

energy available to do work (G) + energy lost to entropy (TS)

equation used to see if a reaction takes place spontaneously

∆ G\= ∆H - T∆S

spontaneity

spontaneous= releases energy

not spontaneous= requires energy

the hydrolysis of ATP is an \_____________ reaction

exergonic (less free energy in products than reactants)

what is hyrolyosis?

ATP reacts with water to form ADP and inorganic phosphate (Pi)

what chemically happens during hydrolysis

a water molecule is split into a proton (H⁺) and a a water molecule is split into a proton (H⁺) and a hydroxyl group (OH⁻) \n -often how polymers are broken down \n -one product gains a proton and the other gains the hydroxyl group

release of energy during ATP hydrolysis comes from...

breaking weaker bonds (with more chemical energy) in the reactants and forming more stable bonds (with less chemical energy) in the products

non-spontaneous reactions are often coupled to....

spontaneous reactions

what drives non-spontaneous reactions?

energetic coupling

energetic coupling

the process by which a spontaneous reaction (-∆G) drives a non-spontaneous reaction (+∆G) \n -requires the net ∆G to be negative

energetic coupling equation

Reaction 1: A—>B. DELTA G>0 \n (energy is consumed) \n \n Reaction 2: b—>C. DELTA G

ATP hydrolysis is an \_______ reaction that can be used to drive a \__________ reaction

exergonic; non-spontaneous

the synthesis of ATP from ADP is a \_______ reaction

endergonic

ADP is an energy \________

acceptor

ATP is an energy \_________

donor

Products have more energy than reactants

Endergonic \n Non-spontaneous \n Energy requiring \n Synthesis \n Anabolic \n (+)DELA G \n Less disordered \n (- )DELTA

Reactants have more energy than products

Exergonic \n Spontaneous \n Energy releasing \n Breakdown \n Catabolic \n (-)DELTAG \n More disordered \n (+)DELTAS

rate of chemical reaction

amount of product formed (or reactants consumed) per unit of time

enzymes

proteins that act as catalyst

catalyst

increase the rate of chemical reactions

all chemical reactions require \________.

an input of energy

TRUE OR FLASE: exergonic reactions DO NOT require an input of chemical energy because they release energy

FALSE, ALL chemical reactions require an input of energy

As a chemical reaction proceeds....

chemical bonds are broken and new ones are formed

transition state

intermediate stage between reactants and products (HIGHLY unstable; large amount of free energy)

reactants adopt at least one \_______ before their conversion into products

transition state

to reach the transition state the reactant must.....

ABSORB ENERGY

activation energy

the energy necessary to reach the transition state

what happens after the transition state is reached?

products are formed & energy is released into the surroundings

how does the height of the energy barrier correspond to the rate of the reaction?

the higher the energy barrier, the slower the reaction; the lower the energy barrier, the faster the reaction

an enzyme works by....

reducing the activation energy (path between reaction)

what does not change in the reaction?

free energy between the reactants and the products (starting and end point of the reaction)

TRUE OR FALSE: Enzymes are consumed in a chemical reaction

FALSE, enzymes emerge unchanged from a chemical reaction

how do enzymes increase the reaction rate without being changed?

enzymes form a complex with the reactants and the products

substrate

reactant in a chemical reaction catalyzed by an enzyme

a reaction catalyzed by an enzyme can be described as....

S + E ⇌ ES ⇌ EP ⇌ E + P

how does protein folding allow for enzyme specificity?

enzymes are folded into three dimensional shapes that bring particular amino acids into close proximity with an ACTIVE SITE

active site

the portion of the enzyme that binds substrate and catalyzes its conversion to the product

enzyme and substrate form \_____ bonds.

weak, non-covalent