Leaving Cert Biology: Cellular Respiration & Fermentation

Comprehensive vocabulary flashcards covering the key concepts, biochemical pathways, stages, and experiments of cellular respiration and fermentation based on the lecture notes.

Aerobic Respiration

The releasing of energy from food (glucose, $C_6H_{12}O_6$) using oxygen.

Catabolic Reaction (in Respiration)

A process that breaks down a large complex molecule (glucose) into smaller molecules (carbon dioxide, $CO_2$, and water, $H_2O$), thereby releasing energy.

Adenosine Diphosphate (ADP)

A low-energy molecule composed of the nitrogen base adenine, the sugar ribose, and two phosphate groups; it combines with a phosphate and energy to form ATP.

Adenosine Triphosphate (ATP)

A high-energy molecule formed when ADP combines with a phosphate and energy; it stores energy in an unstable chemical bond and easily releases it when broken down.

Nicotinamide Adenine Dinucleotide ($NAD^+$)

An energy carrier molecule that accepts high-energy electrons and a proton ($H^+$) to form NADH, which transfers them to the inner membrane of the mitochondria.

Cytosol

The liquid part of the cytoplasm where stage one of respiration (glycolysis) occurs.

Glycolysis

Stage one of respiration; an anaerobic process occurring in the cytosol where a 6-carbon glucose molecule is broken down into two 3-carbon pyruvic acid molecules, releasing a small amount of energy to produce ATP and NADH.

Pyruvic Acid (Pyruvate)

A 3-carbon molecule produced in the cytosol as the primary end product of glycolysis.

Acetyl Coenzyme A (Acetyl CoA)

A 2-carbon molecule formed when pyruvic acid enters the mitochondria under aerobic conditions and loses a carbon as $CO_2$; it subsequently enters the Krebs cycle.

Krebs Cycle

A series of reactions occurring in the mitochondria during stage two of aerobic respiration where acetyl CoA is broken down to produce carbon dioxide ($CO_2$), ATP, and electrons and protons picked up by $NAD^+$ to form NADH.

Electron Transport System

A series of carriers located on the inner membrane of the mitochondria where high-energy electrons carried by NADH release energy to synthesize ATP from ADP and phosphate.

Final Electron Acceptor

Oxygen, which accepts electrons and combines with protons ($H^+$) at the end of the electron transport system to form water ($H_2O$).

Anaerobic Respiration (Fermentation)

The releasing of energy from food without the use of oxygen.

Lactic Acid

A product formed in muscle cells during anaerobic respiration when oxygen is deficient due to excessive exercise, causing muscle cramps.

Alcohol Fermentation

An anaerobic process in yeast cells where pyruvic acid is converted into ethanol and carbon dioxide ($CO_2$).

Iodoform Test

A chemical test to detect the presence of ethanol; uses potassium iodide and sodium hypochlorite heated together, which turn yellow if alcohol is present.

Fermentation Lock

A piece of apparatus containing limewater that allows carbon dioxide bubbles to escape—turning the limewater milky to indicate ongoing fermentation—while preventing oxygen from entering.