Chapters 8-10 AP bio vocab

activation energy

activation energy

EA, initial investment of energy to start a reaction; break bonds ~ energy contorts reactant molecules; aka free energy of activation

active site

a pocket/groove on the enzyme's surface where catalysis occurs; protein molecule determines the framework/shape of the active site; formed by enzyme's amino acids

allosteric regulation

regulatory molecule binds to a separate site --> affects the function of a protein at a different site; inhibition/stimulation of enzyme activity

anabolic pathway

uses ATP; consumes energy to use simple molecules into complicated molecules

catabolic pathway

degradative processes/breakdown pathways; loss of energy; metabolic pathways release energy by breaking down complex molecules into simpler compounds.

coenzyme

cofactor is an organic molecule

cofactor

nonprotein helpers for catalytic activity; bound

competitive inhibitor

reduces the productivity of enzyme by blocking substrates from entering active sites; (to overcome inhibition: increase substrate conc. --> more substrate molecules than inhibitor molecules; entry access to site limited)

cooperativity

allosteric regulation mechanism; amplifies enzyme response to substrate; substrate binds to one active site in a multisubunit enzyme --> triggers shape change in all subunits; increases catalytic activity in other active site

endergonic reaction

absorbs free energy (+ stores it); G increases; ΔG is positive (it's the quantity of E needed to drive the reaction); nonspontaneous

entropy

measure of disorder, or randomness (if a process leads to increased entropy, no input of energy needed - spontaneous)

enzyme

a macromolecule that acts as a catalyst (a chemical agent that speeds up a reaction without being consumed by the reaction)

exergonic reaction

net release (loss) of free energy; G decreases; ΔG is negative; occurs spontaneously (energetically favorable)

feedback inhibition

metabolic control; metabolic pathway halted by inhibitory binding; binds end product to an enzyme that acts early in the pathway

free energy

portion of a system's energy available to perform work; temperature + pressure uniform throughout system

induced fit

change in shape of enzyme's active site to bind tighter (snug) to the substrate; induced by entry of the substrate

metabolism

metabolic pathways: specific molecule -> product; chem reaction builds up/breaks down materials in an organism

noncompetitive inhibitor

impedes enzymatic reactions - binds to another part of enzyme (not active site); changing its conformation; active site becomes less effective at catalyzing substrate to product conversion

substrate

reactant an enzyme acts on; enzyme binds to substrate(s); catalytic action converts substrate into product

thermodynamics

study of the energy transformations that occur in a collection of matter

acetyl CoA

pyruvate (from glycolysis) enters the mitochondrion and is oxidized to a compound called acetyl CoA, which enters the citric acid cycle

alcoholic fermentation

anaerobic process; yeast carries out process to form carbon dioxide and ethanol (ethyl alcohol); steps: 1 - pyruvate -> two-carbon compound acetaldehyde (release of carbon dioxide), 2 - acetaldehyde is reduced by NADH to ethanol

ATP synthase

enzyme that makes ATP from ADP + inorganic phosphate; reverse ion pump; uses the energy of an existing ion gradient

cellular respiration

breaking down glucose + other molecules/oxygen; release stored energy -> ATP; glycolysis, the Krebs cycle, and electron transport chain; C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O;

chemiosmosis

hydrogen ion gradient that drives cellular work; such as ATP synthesis

citric acid cycle

oxidizes pyruvate into three CO2 molecules; 1 ATP per turn by substrate-level phosphorylation; chem energy -> (NAD+) + related electron carrier + coenzyme FAD

cytochrome

iron containing-proteins that are electron carriers in the electron transport chain (besides ubiquinone and oxygen) in mitochondria and chloroplasts of eukaryotic cells and the plasma membranes of prokaryotic cells

electron transport chain

inner membrane of mitochondria; electron carrier molecules (membrane proteins) shuttle electrons during redox reactions; sequentially makes ATP; electrons transferred to the "top," higher-energy end of the chain by NADH; at the "bottom," lower-energy end

facultative anaerobe

makes enough ATP to survive using either fermentation or respiration

glycolysis

first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid

lactic acid fermentation

pyruvate is reduced directly by NADH to form lactate as an end product, with no release of CO2; in humans when oxygen is scarce

obligate anaerobe

organisms that carry out only fermentation or anaerobic respiration

oxidative phosphorylation

ATP synthesis; energy released at each step of the electron transport chain is stored in a form the mitochondrion used to convert ADP -> ATP

proton-motive force

H+ gradient; PE in the form of an electrochemical gradient, pumping of hydrogen ions across biological membranes during chemiosmosis

redox reaction

oxidation-reduction reactions; transfer of 1+ electrons; loss of electrons = oxidation, addition of electrons = reduction

substrate-level phosphorylation

ATP synthesis; enzyme transfers a phosphate group from a substrate molecule to ADP, forms ATP

absorption spectrum

range of a pigment's ability to absorb various wavelengths of light

autotroph

sustain themselves without eating anything derived from other living beings; produce their organic molecules from CO2 + other inorganic raw materials obtained from the environment

C3 plant

initial fixation of carbon occurs via rubisco (a Calvin cycle enzyme) - adds CO2 to ribulose bisphosphate; , 3-phosphoglycerate; stomata partially close on hot, dry days

C4 plant

preface the Calvin cycle with an alternate mode of carbon fixation -> four-carbon compound

Calvin cycle

reduces the fixed carbon (from carbon fixation) -> carbohydrate, by the addition of electrons; needs ATP + NADPH help, makes sugar

CAM plant

photosynthetic adaptation to arid conditions - mesophyll cells of CAM plants store the organic acids from the night in their vacuoles until morning, when the stomata close; open stomata at night; crassulacean acid metabolism = CAM

carbon fixation

initial incorporation of carbon into organic compounds

chlorophyll

green pigment in in the thylakoid membranes of chloroplasts; absorbs light energy

cyclic electron flow

electron flow during light reactions - uses photosystem I but not photosystem II; no production of NADPH or oxygen; produces ATP

electromagnetic spectrum

entire range of radiation; frequencies or wavelengths;

G3P

carbohydrate produced directly from the Calvin cycle; glyceraldehyde 3-phosphate

light reactions

capture solar energy and use it to make ATP and transfer electrons from water to NADP+ , forming NADPH

linear electron flow

occurs during light reactions in photosynthesis; primary pathway, involves both photosystems; produces ATP + NADPH

PEP carboxylase

fixes carbon efficiently when rubisco can't; enzyme present only in mesophyll cells; adds CO2 to phosphoenolpyruvate -> four-carbon product oxaloacetate

photophosphorylation

light reactions use chemiosmosis for the addition of a phosphate group to ADP -> ATP

photorespiration

occurs in the light (photo) and consumes O2 while producing CO2 (respiration); uses ATP, produces no sugar

photosynthesis

6 CO2 + 12 H2O + Light energy -> C6H12O6 + 6 O2 + 6 H2O; light energy used to convert water + carbon dioxide -> oxygen and high-energy carbohydrates such as sugars and starches

photosystems

complexes of chlorophyll molecules organized with other small organic molecules/proteins; reaction-center complex surrounded by several light-harvesting complexes

primary electron acceptor

molecule capable of accepting electrons and becoming reduced in reaction-center complexes (in photosystems)

rubisco

carbon fixation; RuBP carboxylase-oxygenase; most abundant protein in chloroplasts; makes 6C compound that immediately splits in half

heterotroph

get organic material by consuming other organisms

stroma

fluid outside the thylakoids; contains the chloroplast DNA and ribosomes + many enzymes; where calvin cycle happens

thylakoid

membranous system in the form of flattened, interconnected sacs in the chloroplast