Bio Exam 4

• Capacity to do work
• can take many forms
• -mechanical, heat, electric current, light

The energy of motion

• stored energy
• -energy thats stored in chemical bonds & can be transferred from one molecule to another by way of electrons

• what heat energy is measured in
• Heat energy is what most forms of energy can be converted to
• 1 kilocalorie (kcal)= 1000 calories

calorie-amount of heat required to raise temp of water by 1 deg. C.

loss of electrons

gain of electrons

coupled to each other

• energy cant be created or destroyed
• -can only be converted from one form to another
• ex. sunlight energy --> chemical energy (by photosynthesis)

• disorder is more likely than order
• -entropy is always increasing
• -the more order, the more potential energy
• ENTROPY-disorder in universal
• potential=mechanical
• entropy=disorder

• energy available to do work
• -denoted by symbol G (Gibbs free energy)
• Enthalpy-energy contained in a molecule's chemical bonds
• ""=stored away - (entropy x temp.)
• free energy = enthalpy - (entropy x temp.)
• G= H-TS

-^G (triangle) is positive

-^G is negative

• extra energy needed to get a reaction started
• -destabilizes existing chemical bonds

substances that lower the activation energy of a reation

• adenosine triphosphate
• the energy currency of cells
• ATP structure:
• -ribose, a 5-carbon sugar
• -adenine
• -3 phosphates
• it stores energy in the bonds between phosphates

• when bond btwn phosphates is broken:
• ATP-->ADP + Pi (energy is released)

• ADP- adenosine diphosphate
• Pi- inorganic phosphate
• (this reaction is reversible)

• molecules that catalyze reactions in living cells
• -most are protiens
• -lower the activation energy required for a reaction
• -not changed or consumed by the reaction
• -interact with substrates

• molecule that will undergo a reaction
• *binding of an enzyme to a substrate causes the enzyme to change shape, producing a better induced fit btwn the molecules

region of the enzyme that binds to the substrate

• enzyme function affected by its environment
• -factors that can change an enzymes 3D shape can change its function they are:
• pH- enzyme prefer 6-8
• temp- temp. increase, so does reaction. too far above opt. temp can denature enzyme
• regulatory molecules-

molecules that bind to an enzyme to decrease enzyme activity

compete with the substrate for binding to the same active site

bind to sites other than the enzyme's active site

all chemical reactions occuring in an organism

chemical reactions that expend energy to make new chemical bonds

chemical reactions that harvest energy when bonds are broken

• usually metal ions found in the active site participating in catalysis.
• -helps in proper enzymatic activity

• nonprotien organic molecules often used as an electron donor or acceptor in a redox reaction.
• -help in proper enzymatic activity

• series of reactions in which the product of one reaction becomes the substrate for the next reaction.
• -regulated by feedback inhibition

the end product of the pathway is an inhibitor of an earlier enzyme in the pathway

able to produce their own organic molecules through photosynthesis

live on organic compounds produced by other organism

• used by all organisms to extract energy from organic molecules
• -series of reactions that are oxidations, dehydrogenations

• lost electrons are accompanied by hydrogen
• what is actually lost is a hydrogen atom (1 elec. 1 proton)

during redox reactions, electrons carry energy from one molecule to another.

• NAD+ is a electron carrier
• it accepts 2 electrons and 2 proton to become NADH
• this reaction is reversible

final electron receptor is oxygen (O2)

• C6H12O6+6O2-->6CO2+6H2O
• glucose + oxygen-->carbon dioxide + water

final electron acceptor is an inorganic molecule (not O2)

final electron acceptor is an organic molecule

• to produce ATP
• -energy is released from oxidation reaction in form of electrons
• -elec. are shuttled by electron carriers (NAD+) to electron transport chain
• -elec. energy is converted to ATP at the elec. transport chain

-substrate-level phosphorylation: transfering a phosphate directly to ADP from another molecule

and

oxidative phosphorylation: use of ATP synthase and envery derived from a proton (H+) gradient to make ATP

• glycolysis
• pyruvate oxidation
• krebs cycle
• electron transport chain

• converts glucose to pyruvate
• occurs in cytoplasm
• 1 glucose = 2 pyruvate
• products of glycolysis:
• 2NADH
• 2 ATP
• 2 pyruvate
• for glycolysis to cont. :
• NADH be recycled to NAD+ by: aerobic (when O2 is available as final elec. accept.)
• fermentation (when oxy. isnt avail. & organic molecule is final elec. accept.

oxygen availability.

with O2: pyruvate is oxidized to acetyl-CoA & enters Kerbs cycle

w/out O2: pyruvate reduced to oxidize NADH back to NAD+