Cells and Energy: Cellular Respiration and ATP

Vocabulary flashcards covering cellular energy, ATP structure and function, the three stages of aerobic cellular respiration (glycolysis, Krebs cycle, ETC), and anaerobic fermentation pathways.

ATP (Adenosine Triphosphate)

The chief energy-storing molecule for the cell that is used to power and run all cellular processes.

Adenosine

The component of an ATP molecule formed by combining adenine and ribose sugar.

Structural Components of ATP

A nitrogenous base (adenine), a five-carbon sugar (ribose), and three phosphate groups.

Phosphate Bond Energy Storage

The mechanism where usable chemical energy is stored within the chemical bonds linking phosphate groups in ATP.

ADP (Adenosine Diphosphate)

The lower-energy molecule formed alongside a free phosphate group when ATP breaks its terminal phosphate bond to release energy.

Glucose

A short-term energy storage sugar ($C_6H_{12}O_6$) made by plants via photosynthesis that enters the cell to assist in generating ATP.

Cellular Respiration

The process by which cells break down glucose to release energy, producing ATP, carbon dioxide ($CO_2$), and water ($H_2O$).

Reactants of Cellular Respiration

Glucose ($C_6H_{12}O_6$) and oxygen ($O_2$).

Products of Cellular Respiration

Carbon dioxide ($CO_2$), water ($H_2O$), and ATP.

Organelles of Cellular Respiration

The cytoplasm and the mitochondria.

Glycolysis

Step 1 of cellular respiration, occurring in the cytoplasm, where one molecule of glucose is split into two molecules of pyruvate.

ATP Activation Energy in Glycolysis

$2\,\text{ATP}$ molecules required to initiate glycolysis and split the glucose molecule.

Total vs. Net ATP in Glycolysis

Glycolysis produces a total of $4\,\text{ATP}$, yielding a net gain of $2\,\text{ATP}$ after accounting for the $2\,\text{ATP}$ used at the start.

Pyruvate

A three-carbon organic acid produced at the end of glycolysis from splitting a six-carbon glucose molecule.

$\text{NAD}^+$ / $\text{NADH}$

Coenzyme electron carriers that become reduced to $\text{NADH}$ by accepting high-energy electrons during glycolysis and the Krebs cycle.

Aerobic Respiration

The stages of cellular respiration (Krebs cycle and electron transport chain) that occur inside the mitochondria in the presence of oxygen.

Cristae

The inner membrane folds of the mitochondrion where the electron transport chain takes place.

Mitochondrial Matrix

The inner fluid-filled space of the mitochondrion where the Krebs cycle takes place.

Krebs Cycle (Citric Acid Cycle)

Step 2 of cellular respiration, occurring in the mitochondrial matrix, where pyruvate converts to acetyl-CoA, producing carbon dioxide ($CO_2$), ATP, $\text{NADH}$, and $\text{FADH}$.

Acetyl-CoA

The intermediate molecule formed from pyruvate that enters the Krebs cycle in the mitochondrial matrix.

Electron Transport Chain (ETC)

Step 3 of cellular respiration, taking place along the cristae, which consumes oxygen ($O_2$), utilizes $\text{NADH}$ and $\text{FADH}$, and produces $32\,\text{ATP}$ and water ($H_2O$).

Anaerobic Respiration

The cellular pathway that follows glycolysis when oxygen is not present, occurring entirely in the cytoplasm.

Alcohol Fermentation

A form of anaerobic respiration carried out by yeast and certain bacteria that converts pyruvate into ethanol (alcohol) and carbon dioxide ($CO_2$).

Lactic Acid Fermentation

A form of anaerobic respiration occurring in animal muscle cells and certain bacteria that converts pyruvate into lactic acid when oxygen is depleted.