Photosynthesis and Chloroplast Function

Vocabulary flashcards covering the raw materials, products, chloroplast structure, light and dark phases, energy carriers, and ecological importance of photosynthesis.

Photosynthesis

The building up of carbohydrates (glucose) from carbon dioxide and water using radiant energy from the sun trapped by chlorophyll, with the release of oxygen.

Chloroplast

The organelle in green plant cells bounded by a double-membrane and containing grana, intergrana, thylakoids, and stroma where photosynthesis takes place.

Light phase

The light-dependent stage of photosynthesis that occurs in the grana of chloroplasts, where radiant energy is transformed into chemical energy to split water and produce ATP.

Dark phase (Calvin cycle)

The light-independent stage of photosynthesis occurring in the stroma of chloroplasts, in which carbon dioxide combines with energy-rich hydrogen atoms using energy released from ATP to form glucose.

Photolysis

The light-phase process in which water molecules are split into energy-rich hydrogen atoms (transferred to the dark phase) and oxygen atoms (released into the atmosphere as a gas).

Chlorophyll

The green pigment located in the thylakoids of chloroplasts that absorbs radiant energy from the sun.

Granum

A stacked thylakoid structure inside a chloroplast where chlorophyll absorbs radiant energy during the light phase.

Stroma

The fluid-filled area within the chloroplast where the dark phase (Calvin cycle) of photosynthesis occurs.

ATP (adenosine triphosphate)

The energy carrier in living cells consisting of adenosine and three phosphate molecules, formed during the light phase to carry energy to the dark phase.

ADP (adenosinediphosphate)

A molecule consisting of adenosine and two phosphate molecules that is formed when ATP is broken down to release energy, or combined with a phosphate molecule to store energy.

Glucose

An energy-rich carbohydrate synthesized during the dark phase of photosynthesis and stored in plants as starch.

Starch

The storage polysaccharide into which excess glucose is converted within the plant.

Raw materials of photosynthesis

Carbon dioxide ($CO_2$) from the atmosphere, water ($H_2O$) from the soil, radiant energy from the sun, chlorophyll in the chloroplasts, and enzymes.

Equation for photosynthesis

$CO_2 + H_2O + \text{Radiant E} \rightarrow \text{Glucose} + O_2$ (facilitated by chlorophyll and enzymes).

Limiting factor (Light intensity context)

A condition such as carbon dioxide availability that caps photosynthesis; when light intensity becomes too high, stomata close and carbon dioxide becomes the factor restricting the rate.

Heterotrophic organisms (Photosynthesis context)

Organisms provided with food via photosynthesis, as fats and proteins are synthesized from the glucose and starch produced by plants.