Overview of Digestion and Cellular Respiration (Vocabulary)

Vocabulary-style flashcards covering the key terms and definitions related to digestion and the four stages of cellular respiration.

Digestion

The process of breaking down food into chemical components and absorbing them into the bloodstream.

Cellular respiration

The four-stage process that converts nutrients (like glucose) into ATP, mainly occurring in the mitochondria.

Glycolysis

The first stage of cellular respiration in the cytoplasm; splits glucose into two pyruvate and yields net 2 ATP and 2 NADH.

Energy investment phase

Glycolysis phase where 2 ATP are used to activate glucose and form a six-carbon sugar diphosphate.

Energy harvesting phase

Glycolysis phase where the split three-carbon molecules are converted to pyruvate, producing ATP and NADH.

Pyruvate

A three-carbon molecule produced by glycolysis; transported into mitochondria and oxidized to acetyl-CoA.

NADH

A high-energy electron carrier produced during glycolysis and other steps; donates electrons to the electron transport chain.

Pyruvate oxidation

Process converting pyruvate to acetyl-CoA in the mitochondria; NADH is produced and CO2 is released.

Acetyl-CoA

Two-carbon molecule that enters the citric acid cycle after pyruvate oxidation.

Citric acid cycle (Krebs cycle)

Mitochondrial cycle where acetyl-CoA is oxidized; produces NADH, FADH2, ATP, and CO2; starts and ends with oxaloacetate.

Oxaloacetate

Starting and ending compound of the citric acid cycle.

FADH2

A high-energy electron carrier produced in the citric acid cycle and used in the electron transport chain.

Carbon dioxide (CO2)

A waste product produced during pyruvate oxidation and the citric acid cycle; expelled from the body.

Electron transport chain (ETC)

A series of membrane-bound carriers in mitochondria that transfer electrons, pump protons, and drive ATP synthesis.

ATP synthase

The enzyme that uses the proton gradient to synthesize ATP from ADP and Pi.

Oxygen (O2) as terminal electron acceptor

Oxygen accepts electrons at the end of the ETC, becoming water.

Water

The byproduct formed when oxygen accepts electrons at the end of the electron transport chain.

ATP yield (per glucose)

Total ATP produced during cellular respiration; about 32–36 ATP per glucose, commonly averaged as 36.

Glucose

A six-carbon sugar that is the primary substrate for glycolysis and the energy source for cellular respiration.

Process produce

ATP

Final in electron transport chain

O2 brought from bloodstream to find electron acceptor and CO2 produced as byproduct is released.

Goal of cellular respiration

transfer energy from food we eat to ATP our bodies use.

Process start with

meal

Process end with

capture energy from complete break down of nutrients into energy and CO2