Photosynthesis

Autotrophic Nutrition

The process by which organisms produce their own food, typically through photosynthesis or chemosynthesis.

Heterotrophic Nutrition

The process by which organisms obtain food by consuming other living things.

Photoautotrophs

Organisms that use light energy to synthesize organic compounds from carbon dioxide.

Chemoautotrophs

Organisms that obtain energy by oxidizing inorganic substances to produce organic compounds.

Wavelength of Light

The distance between successive peaks of a wave, which determines its color and energy.

Particle-Like Behavior of Light

Light can behave as particles called photons, which carry energy.

Wavelike Behavior of Light

Light propagates through space as a wave, exhibiting properties like interference and diffraction.

Effective Wavelengths for Photosynthesis

Red and blue wavelengths are most effectively used in photosynthesis.

Action Spectrum

A graph that shows the effectiveness of different wavelengths of light in promoting photosynthesis.

Absorption Spectrum

A graph that measures the amount of light absorbed by pigments at different wavelengths.

Chlorophyll Absorption Spectrum vs. Action Spectrum

The absorption spectrum shows specific wavelengths absorbed by chlorophyll, while the action spectrum demonstrates overall photosynthetic activity, showing that other pigments also contribute.

Chloroplast Structure and Function

Chloroplasts contain thylakoids for light absorption and stroma for the Calvin cycle, enabling efficient photosynthesis.

Light Reactions

The first stage of photosynthesis occurring in the thylakoid membranes, converting solar energy to chemical energy.

Calvin Cycle

The light-independent reactions of photosynthesis occurring in the stroma, where carbon fixation takes place.

Chemiosmosis

The process of ATP production in chloroplasts and mitochondria through the movement of hydrogen ions across a membrane.

Redox Reactions

Reactions involving the transfer of electrons, crucial in the processes of oxidation and reduction during photosynthesis.

Rubisco

An enzyme involved in fixing carbon dioxide in the Calvin cycle; its activity is affected by the concentration of oxygen.

Photorespiration

A process that occurs when rubisco reacts with oxygen instead of carbon dioxide, leading to a decrease in photosynthetic efficiency.

Rf Value in Chromatography

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

Components of Photosystem

Photosystems contain chlorophyll, carotenoids, and proteins that capture light energy and transfer electrons.

Cyclic Electron Flow

A process where electrons are recycled in the light reactions to produce additional ATP without NADPH.

Noncyclic Electron Flow

The process where electrons flow from water, through the photosystems, to NADP+, generating both ATP and NADPH.

C3 Plants

Plants that fix carbon dioxide directly into a three-carbon compound during photosynthesis.

C4 Plants

Plants that initially fix carbon dioxide into a four-carbon compound to minimize photorespiration.

CAM Plants

Plants that fix carbon dioxide at night to reduce water loss during the day.

Photosynthetic Products

Glucose and oxygen are produced as a result of photosynthesis, sustaining plant metabolism and releasing oxygen.

Light-Dependent Reactions

The series of reactions in photosynthesis that require light to produce ATP and NADPH.

Light-Independent Reactions

Also known as the Calvin Cycle, these reactions do not require light and use ATP and NADPH to synthesize glucose.