Energy Production

ATP structure components

adenine, ribose, three phosphate groups

ATP hydrolysis reaction

ATP + H₂O → ADP + Pi + energy

Hydrolysis of two phosphates from ATP

AMP formation

ATP synthesis energy source

oxidation of food molecules

Mechanical work powered by ATP

muscle contraction, cytoplasmic flow, chromosome movement

Transport work powered by ATP

pumping substances across membranes against gradient

Chemical work powered by ATP

driving endergonic reactions like polymer synthesis

Definition of oxidation

loss of electrons

Definition of reduction

gain of electrons

NAD⁺ reduced form

NADH + H⁺

NADH oxidized form

NAD⁺

FAD reduced form

FADH₂

FADH₂ oxidized form

FAD

Definition of energy

capacity to do work

Forms of energy

kinetic, potential, chemical

Cell ability with energy

transform energy from one form to another

Definition of substrate‑level phosphorylation

phosphorylation of ADP using energy released during conversion of high‑energy substrate to low‑energy product

Definition of oxidative phosphorylation

phosphorylation of ADP coupled to electron transport chain and proton gradient

ETC involvement in substrate‑level phosphorylation

not involved

ETC involvement in oxidative phosphorylation

required

Location of substrate‑level phosphorylation

glycolysis and TCA cycle

Location of oxidative phosphorylation

inner mitochondrial membrane

ATP yield from substrate‑level phosphorylation

limited ATP

ATP yield from oxidative phosphorylation

major ATP yield

Location of electron transport chain

inner mitochondrial membrane

Function of electron transport chain

create electrochemical proton gradient to power oxidative phosphorylation

Complex I name

NADH dehydrogenase

Complex I components

FMN, Fe‑S

Complex I function

transfers electrons from NADH to CoQ and pumps protons

Complex II name

succinate dehydrogenase

Complex II components

Fe‑S

Complex II function

transfers electrons from FADH₂ to CoQ, does not pump protons

Complex III components

cytochrome b, Fe‑S, cytochrome c₁

Complex III function

transfers electrons from CoQ to cytochrome c and pumps protons

Complex IV name

cytochrome c oxidase

Complex IV components

cytochrome a, cytochrome a₃

Complex IV function

transfers electrons to O₂ and pumps protons

Complex V name

ATP synthase

Complex V function

synthesizes ATP using proton gradient

Source of NADH and FADH₂

glycolysis, TCA cycle, oxidation of fatty acids

Final electron acceptor in ETC

oxygen

Product formed when O₂ accepts electrons and protons

water

Chemiosmotic theory explanation

energy from electron transport pumps H⁺ into intermembrane space creating proton gradient

Proton gradient effect

protons flow back into matrix via ATP synthase releasing energy

ATP yield from NADH oxidation

2.5 ATP

ATP yield from FADH₂ oxidation

1.5 ATP

Cyanide and carbon monoxide target

cytochrome aₐ₃, block electron transfer to O₂

Rotenone target

complex I

Antimycin target

complex III

Oligomycin target

ATP synthase, prevents ADP → ATP conversion

Uncoupling agents examples

dinitrophenol, high‑dose aspirin

Effect of uncoupling agents

allow protons to reenter matrix without ATP synthase, uncoupling electron transport and ATP production

Metabolic effect of cyanide poisoning

proton gradient disappears

ETC complex unable to generate sufficient free energy

complex II

Energy released during electron flow

used to pump protons into intermembrane space

Protons pumped at complex I

yes

Protons pumped at complex II

no

Protons pumped at complex III

yes

Protons pumped at complex IV

yes

Definition of electron transport chain

series of electron carriers in inner mitochondrial membrane

Alternate name for electron transport chain

respiratory chain

Role of coenzyme Q

mobile electron carrier between complexes

Role of cytochrome c

mobile electron carrier between complex III and IV

Overall process name

oxidative phosphorylation

Reason for name

phosphorylation of ADP to ATP coupled to transfer of electrons through ETC to O₂

Energy captured in cellular respiration

used to form ATP

Fuel molecules in cellular respiration

oxidized within cells

Hydrolysis of ATP importance

provides energy for mechanical, transport, and chemical work

ATP synthase classification

complex V of ETC

Proton gradient description

electrochemical gradient across inner mitochondrial membrane

Effect of oligomycin

inhibits ATP synthase, prevents ATP formation

Effect of rotenone

inhibits complex I, blocks NADH electron transfer

Effect of antimycin

inhibits complex III, blocks electron transfer

Effect of cyanide and CO

block complex IV, prevent electron transfer to O₂

Effect of uncoupling agents

destroy link between electron transport and ATP synthesis

Self‑assessment: cyanide effect

proton gradient disappears

Self‑assessment: complex unable to power ATP synthesis

complex II