ap bio unit 3: cellular energetics

thermodynamics

the study of energy transformations in matter

entropy

measure of disorder in the universe

metabolism

the sum of all chemical reactions in a cell that transform energy and matter

metabolic pathways

series of linked chemical reactions that either break down complex molecules or build complex molecules, sequential

ATP

TRI phosphate

3 PHOSPHATES

energy source

ADP

DI phosphate

2 PHOSPHATES

undergoes phosphorylation to become ATP

phosphorylation

the addition of a phosphate group to a molecule

ASE

enzyme suffix

enzyme

proteins that catalyze reactions by lowering the activation energy

brings molecules together—> react faster

endergonic

reactions that requires energy

exergonic

reactions that release energy

substrate

reactants that enzymes act upon, what they’re catalyzing

cofactors

non protein molecules that bind to enzymes and assist enzyme function

metallic ions (iron, copper, zinc, etc), small organic compounds (coenzymes)

denaturation

a loss of both structure and function of an enzyme due to conditions that cause it to unfold from its normal conformation

cause: temperature changes, pH changes, and chemical environments

can sometimes be reversed if enzyme is placed back into optimal conditions

brownian motion

the random movement of particles

all reactions are caused by random movement

competitive inhibitors

molecules that result in a reduction of enzyme activity by blocking substrates from binding to the active site

can be reversed through increased substrate concentration

saturation

the state or process where no more of something can be absorbed, combined with, or added

high concentrations of substrate will initially increase enzyme activity, but ti will eventually peak, since all of the enzymes will be occupied

active site

area for substrate to bind to enzymes

substrate has to be exactly compatible with this area, shape and charge

enzyme-substrate complex

substrate and active site bonded together

both changed shape slightly

noncompetitve inhibitors

molecules that bind to an allosteric site on an enzyme, changing the shape of the active site and preventing substrates from binding

allosteric site

areas of the enzyme other than the active site, the place where substrates bind

allosteric regulation

regulatory molecules bind to an allosteric site, can either be an activator or an inhibitor

feedback inhibition

when the end product of a metabolic pathway is an allosteric inhibitor to an early enzyme in the same pathway (cycle)

photosynthesis

the conversion of light energy to chemical energy

autotrophs

organisms that produce their own food

heterotrophs

organisms that don’t make their own food, so they live off of other organisms

cyanobacteria

early prokaryotes capable of photosynthesis, oxygenated the atmosphere of early earth

leaves

location of photosynthesis on the plant

stomata

pores in leaves that allow CO2 in and O2 out

chloroplast

organelle where photosynthesis takes place

stroma

aqueous internal fluid of the chloroplast, location of the calvin cycle in photosynthesis

thylakoids

stacked flattened sacs in the chloroplast containing chlorophyll pigments, location of the light reactions in photosynthesis

pigments

organic molecules that absorb certain wavelengths of visible light, contains elections that absorb light energy for photosynthesis

chlorophyll a

primary pigment for photosynthesis

accessory pigments

not the main pigments, expand the useable light spectrum and protect the chlorophyll from damage

chlorophyll b and carotenoids

6CO2 + 6H2O + light energy —> C6H12O6 + 6O2

simplified formula of photosynthesis

redox reactions

a series of reactions involving the complete or partial transfer of one or more elections from one reactant to another

oxidation and reduction

photosynthesis

oxidation

the loss of electrons in a reaction

reduction

the gain of electrons in a reaction

photons

particles of energy

light reactions

first step in photosynthesis that occurs in the thylakoid membrane and converts solar energy to chemical energy (ATP, NADPH) which will later be used in the calvin cycle

photosystems

protein complexes that are reaction centers and capture light for photosynthesis

photosystem 2 = 680nm

photosystem 1 = 700nm

2 is first, 1 is last

electron transport chain (etc)

proteins embedded in the membrane of chloroplast / mitochondria that transfers electrons

thylakoid lumen

aqueous environment inside of the thylakoid in a chloroplast

photophosphorylation

the process of electrons being removed from water and passed from PSII and PSI before ending in NADPH

chemiosmosis

the process of H+ flowing down its gradient, passing through ATP synthase, and driving ATP production

NADP+

electron accepting molecule in photosynthesis

NADPH

electron carrier molecule in photosynthesis

“taxi cab”

NAD+

electron accepting molecule in cellular respiration

NADH

electron carrier molecule in cellular respiration

“taxi cabs”

mesophyll

cells that make up the interior tissue of leaves

calvin cycle

2nd step in photosynthesis that uses ATP and NADPH to produce carbohydrates, light independent

three phases of calvin cycle

1.) carbon fixation

2.) reduction

3.) regeneration of RuBP

carbon fixation

1st phase of the calvin cycle where CO2 attaches to RuBP, turning it into 3-PGA, catalyzed by enzyme rubisco, completed three times

reduction

2nd phase of the calvin cycle where ATP and NADPH convert 3-PGA into G3P, a sugar

regeneration of RuBP

5 G3P molecules from reduction phase regenerate RuBP, 3 ATP is used

photorespiration

when plants close their stomata on hot days to prevent water loss

more O2 is present, rubisco binds to O2 and uses ATP, doesn’t produce any sugar

BAD for a plant