1. C 1.3 SL Photosynthesis

Photosynthesis

The process by which green plants use sunlight to synthesize foods from carbon dioxide and water.

Photoautotrophs

Organisms that produce their own food using light energy.

Heterotrophs

Organisms that cannot produce their own food and rely on consuming other organisms.

Electromagnetic spectrum

The range of all types of electromagnetic radiation, including visible light used in photosynthesis.

Visible light

The portion of the electromagnetic spectrum that is visible to the human eye, between 400-700 nm.

Dispersion

The separation of visible light into its component colors.

Chlorophyll

The green pigment found in plants that absorbs light for photosynthesis.

Photolysis

The process by which light energy splits a water molecule during photosynthesis.

Granum

A stack of thylakoids within a chloroplast where light-dependent reactions occur.

Accessory pigments

Pigments that assist chlorophyll in capturing light energy by absorbing different wavelengths.

Carotenoids

Accessory pigments that impart yellow, orange or red colors to plants.

Xanthophylls

A type of carotenoid that produces yellow pigments in plants.

Anthocyanins

Water-soluble pigments that can appear red, purple, or blue depending on pH.

Thylakoid membranes

Membranes within the chloroplast where the light-dependent reactions of photosynthesis occur.

ATP (Adenosine Triphosphate)

The main energy carrier in cells, produced in the light-dependent reactions.

Carbon dioxide (CO2)

A reactant in photosynthesis that plants absorb from the atmosphere.

Oxygen (O2)

A by-product of photosynthesis, produced during the photolysis of water.

Light-dependent reactions

Reactions that capture light energy to make ATP and NADPH, occurring in the thylakoid membranes.

Light-independent reactions

Reactions that use ATP and NADPH to fix carbon from CO2, occurring in the stroma of the chloroplast.

Limiting factors

Factors that can limit the rate of photosynthesis when they are below optimal levels.

Chloroplasts

Organelles found in plant cells where photosynthesis takes place.

Photosynthetic efficiency

A measure of how effectively photosynthetic organisms convert light energy to chemical energy.

Rf value

The ratio of the distance traveled by the pigment to the distance traveled by the solvent front in chromatography.

Action spectrum

A graph showing the relative effectiveness of different wavelengths of light in photosynthesis.

Absorption spectrum

A graph showing the relative amount of light absorbed by different pigments at each wavelength.

Beta-carotene

A carotenoid that absorbs blue and green light, reflecting orange; found in carrots.

Lutein

A type of xanthophyll carotenoid that contributes to the yellow color in egg yolks and plant leaves.

Photosynthetic pigments

Molecules that absorb light energy for use in photosynthesis.

Photons

Particles of light that provide the energy needed for photosynthesis.

Stroma

The fluid-filled space surrounding the thylakoids in chloroplasts where light-independent reactions occur.

Pondweed experiment

An experiment used to measure the rate of oxygen production as an indicator of photosynthesis.

CO2 enrichment

Increasing atmospheric CO2 levels in controlled conditions to enhance photosynthesis and plant growth.

Spectrophotometry

A method used to measure how much light is absorbed by pigments.

Solvent front in chromatography

The line on a chromatography strip marking the furthest point a solvent has traveled.

Photoproduction

The production of oxygen and other byproducts during photosynthesis through the absorption of light.