AP Biology Unit 3

first law of thermodynamics

energy cannot be created nor destroyed

second law of thermodynamics

everything is gradually shifting towards a state of chaos and disorder

entropy

inevitable increase of disorder and randomness without a biological system

enzymes

biological catalysts that speed up biochemical reactions

active site

where the substrates binds to in an enzyme

allosteric site

the portion of the enzyme that is not an active site

substrate

the reactants being catalyzed

induced fit

the enzyme changes shape to fit the substrate shape

metabolism

the total amount of chemical reactions that transform matter and energy

metabolic pathway

a series of specific steps that alter a certain molecule and produce a certain product

catabolic pathways

pathways that break down large molecules

anabolic pathways

pathways that create molecules

exergonic reactions

reactions that release free energy

endergonic reactions

reactions that absorbs free energy

spontaneous reaction

reaction where no outside input of energy is required

ATP structure

made of adenine, ribose, and 3 endergonic reactions to power cell work

ATP coupling

ATP couples exergonic reactions to endergonic reactions to power cell work

phosphorylation

receiving a phosphate group

activation energy

the energy needed for a reaction to start

denaturation

typically irreversible changes in the conformational change

denaturation factors

extreme temperatures and pH

enzyme inhibition

reduces the activity of specific enzymes

competitive inhibition

inhibitor binds to the active site

non-competitive inhibitors

inhibitor binds to the allosteric site and changes the shape of the active site

energy balance

energy input must exceed energy loss to maintain order and to power cellular processes

significant loss of energy

results to death

sequential energy-related pathways

a product of a reaction in one pathway is typically the reactant of another

autotrophs

organisms that create their own energy

heterotrophs

organisms that obtain energy from outside sources

cyanobacteria

responsible for atmospheric O2; foundation of eukaryotic photosynthesis

mesophyll

site of chloroplasts in leaves

stomata

pores in the leaf surfaces that allow for the exchange of gases

chlorophyll

in the thylakoid membrane; capture sunlight’s energy and converts to charged electrons

photosynthesis

6 CO2 + H2O → C6H12O6 + 6 O2

reduction in photosynthesis

CO2 is reduced to glucose

oxidation in photosynthesis

H2O is oxidized into O2

light reaction inputs

H2O, ADP, NADP+

light reaction outputs

O2, ATP, NADPH

light reaction site

thylakoid membrane in the photosystems

light reaction function

converts the light energy into chemical energy (NADPH and ATP)

photosystems

light capturing unit in a chloroplast thylakoid membrane

ATP synthase

enzyme that creates ATP when protons pass through (couples the diffusion of H+)

chemiosmosis

mechanism in which ATP is generated through H+ movement down the conc. gradient, providing energy to phosphorylate ADP into ATP

Calvin cycle

reduces CO2 to G3P with products in light dependent reactions; includes carbon fixation, reduction, and regeneration; purpose is to produce sugars

rubisco

enzyme that catalyzes the attachment of CO2 to RuBP

Calvin cycle input

CO2, ATP, NADPH

Calvin cycle output

G3P for synthesizing sugars, ADP, NADP+

cellular respiration

harvest chemical energy stored in organic molecules and use it to generate ATP

catabolic breakdown of glucose (formula)

C6H12O6 + O2 → CO2 + H2O + energy

reduction in cellular respiration

O2 is reduced into H2O

oxidation in cellular respiration

C6H12O6 is oxidized into CO2

aerobic respiration process

glycolysis → pyruvate oxidation → Krebs cycle → oxidative phosphorylation and chemiosmosis

glycolysis

splits glucose into 2 pyruvate in the cytosol

substrate level phosphorylation

a phosphate group transferred from a substrate to ADP; a part of glycolysis

pyruvate oxidation

pyruvate is oxidized into acetyl CoA in the mitochondrial matrix

Krebs cycle site

mitochondrial matrix

Kreb cycle input

acetyl CoA

Krebs cycle outputs

ATP, NADH, FADH2

Krebs cycle purpose

to donate electrons to the electron transport chain (NADH and FADH2)

oxidative phosphorylation inputs

NADH, FADH2

oxidative phosphorylation outputs

26-28 ATP

parts of oxidative phosphorylation

ETC and chemiosmosis

electron transport chain (ETC)

a chain of proteins transferring electrons; electron transfer releases energy that pumps H+ from the matrix to the intermembrane space, creating the electrochemical gradient

decoupling oxidative phosphorylation

in extreme cold environments; generate heat

anaerobic respiration

generates ATP in the absence of O2; uses fermentation

types of fermentation

alcoholic fermentation and lactic acid fermentation