Aerobic Respiration and Cellular Energy Vocabulary

Vocabulary flashcards covering key terms, structures, and processes of aerobic cellular respiration, anaerobic fermentation, and macromolecule breakdown based on the lecture material.

ATP

A usable form of chemical energy converted from carbohydrates that is required to fuel cellular work in living organisms.

Aerobic cellular respiration

The metabolic process that uses molecular oxygen ($O_2$) and glucose to generate $ATP$, producing water ($H_2O$) and carbon dioxide ($CO_2$) as waste products.

Cristae

The extensive folds of the inner mitochondrial membrane that increase the surface area for membrane proteins used during oxidative phosphorylation to make $ATP$.

Matrix

The innermost compartment of a mitochondrion that contains $DNA$, ribosomes, and the enzymes necessary for pyruvate oxidation and the Krebs cycle.

Glycolysis

An anaerobic series of ten enzyme-catalyzed reactions in the cytoplasm that splits one six-carbon glucose molecule into two three-carbon pyruvate molecules, yielding a net output of $2$ $ATP$ and $2$ $NADH$.

Acetyl-CoA

The compound formed in the mitochondrial matrix when a three-carbon pyruvate is oxidized into a two-carbon acetyl group and attached to coenzyme A, serving as the input for the Krebs cycle.

Krebs cycle

A closed-loop pathway of eight enzyme-catalyzed reactions in the mitochondrial matrix that regenerates oxaloacetate while producing $1$ $ATP$, $3$ $NADH$, and $1$ $FADH_2$ per incoming acetyl-CoA.

Chemiosmosis

The mechanism of generating $ATP$ in which energy stored in an $H^+$ ion electrochemical gradient across a membrane is used by $ATP$ synthase to power the synthesis of $ATP$.

Electron transport chain

A series of redox reactions involving four protein complexes and mobile electron carriers in the inner mitochondrial membrane that pass electrons to oxygen, the final electron acceptor, to form water.

ATP synthase

A membrane protein complex that acts like a generator, turned by the force of $H^+$ ions diffusing down their electrochemical gradient to catalyze the addition of a phosphate to $ADP$, forming $ATP$.

Total ATP yield

The total amount of $ATP$ generated from the complete oxidation of one glucose molecule during aerobic cellular respiration, which is generally around $36$ $ATP$.

Interdependence of photosynthesis and respiration

The metabolic relationship where the substrates of aerobic cellular respiration ($O_2$ and carbohydrates) are the products of photosynthesis, and the substrates of photosynthesis ($CO_2$ and $H_2O$) are the products of aerobic cellular respiration.

Obligate anaerobes

Microorganisms, such as methanogens, that can only live in environments lacking molecular oxygen ($O_2$).

Fermentation

An anaerobic pathway combining glycolysis and $NAD^+$ regeneration, where electrons from $NADH$ are transferred to an organic molecule so that glycolysis can continue producing $ATP$ without oxygen.

Lactic acid fermentation

A fermentation process in animal cells and certain bacteria where electrons from $NADH$ are transferred directly to pyruvate, reducing it to lactic acid and regenerating $NAD^+$.

Alcohol fermentation

A fermentation process in yeast where pyruvate releases carbon dioxide ($CO_2$) to form acetaldehyde, which is then reduced by $NADH$ to form ethanol and regenerate $NAD^+$.

Proteases

A variety of cellular enzymes that hydrolyze proteins into individual amino acids.

Lipases

Enzymes that hydrolyze triacylglycerol molecules into glycerol and three fatty acids.

Glycerol-3-phosphate

A phosphorylated three-carbon molecule formed from glycerol that enters aerobic respiration as an intermediate of glycolysis.