Biology: Photosynthesis, Cellular Respiration, and Carbon Cycle Key Concepts

Carbon Cycle

The process by which carbon moves between the atmosphere, living organisms, soil, oceans, and rocks.

Autotroph

An organism that makes its own food using sunlight or chemical energy.

Heterotroph

An organism that cannot make its own food and must consume other organisms.

Producers

Organisms that produce their own food and form the base of the food chain.

Consumers

Organisms that get energy by eating other organisms.

Decomposers

Organisms that break down dead organisms and recycle nutrients.

Photosynthesis

The process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen.

ATP, ADP

ATP is the main energy molecule in cells; ADP is the lower-energy form.

NADP+, NADPH

Energy carriers that transport electrons during photosynthesis.

Chloroplast

An organelle where photosynthesis takes place.

Chlorophyll

A green pigment that absorbs light energy for photosynthesis.

Thylakoids

Flattened membrane sacs inside the chloroplast where light-dependent reactions occur.

Grana / Granum

Stacks of thylakoids inside the chloroplast.

Stroma

The fluid-filled space in the chloroplast surrounding the thylakoids.

Light-Dependent Reactions

The first stage of photosynthesis that uses light to make ATP and NADPH.

Calvin Cycle

The second stage of photosynthesis that uses ATP and NADPH to make glucose.

Oxygen & Carbon Dioxide

Oxygen is used to release energy from glucose; carbon dioxide is a waste product.

Glucose (Sugar)

A simple sugar that stores energy for cells.

Cellular Respiration

The process cells use to convert glucose into ATP energy.

Mitochondria

An organelle where most cellular respiration occurs.

Aerobic Respiration

Cellular respiration that requires oxygen.

Anaerobic Respiration

Cellular respiration that occurs without oxygen.

Glycolysis

The first step of cellular respiration where glucose is broken into pyruvate.

Krebs Cycle

A series of reactions that produce energy carriers after glycolysis.

Electron Transport Chain (ETC)

The final stage of cellular respiration where most ATP is produced.

Cytoplasm / Cytosol

The jelly-like fluid inside the cell where glycolysis occurs.

Fermentation

An anaerobic process that allows glycolysis to continue without oxygen.

Alcoholic Fermentation

A type of fermentation that produces alcohol and carbon dioxide.

Lactic Acid Fermentation

A type of fermentation that produces lactic acid.

NAD+, NADH / FAD+, FADH₂

Energy carriers that transport electrons during cellular respiration.

Pyruvate

The molecule produced after glucose is broken down in glycolysis.

ATP Synthase

An enzyme that produces ATP during the ETC.