Photosynthesis: Light Energy to Chemical Energy C1.3

Photosynthesis

The process by which cells synthesise organic compounds (e.g. glucose) from inorganic molecules (CO2 and H2O) in the presence of sunlight

Photosynthetic Pigment

Pigments in photosynthetic organisms that capture light energy from the sun to create chemical energy (ATP)

ATP

Chemical energy used to synthesise organic compounds via anabolic reactions in photosynthetic organisms

Chlorophyll

The main photosynthetic pigment in plants responsible for capturing light energy

Calvin Cycle

The process in photosynthesis where hydrogen is combined with carbon dioxide to form complex organic compounds using ATP

Oxygen

A byproduct of photosynthesis released from stomata in plants, algae, and cyanobacteria

Chromatography

An experimental technique to separate photosynthetic pigments using different speeds of travel through a stationary phase

Rf Value

A calculated value in chromatography representing the distance a component travels divided by the distance the solvent travels

Light Spectrum

The full range of radiation energy emitted by the sun, with visible light ranging from 400nm to 700nm

Absorption Spectrum

Indicates the wavelengths of light absorbed by pigment molecules like chlorophyll in photosynthetic organisms

Action Spectrum

Indicates the overall rate of photosynthesis at each wavelength of light, showing the effectiveness of light absorption

Law of Limiting Factors

States that the rate of a biochemical process is limited by the factor closest to its minimum value

Rubisco

An enzyme that fixes carbon dioxide in the Calvin Cycle of photosynthesis, requiring ATP for the process

Carbon Dioxide Enrichment

Increasing the amount of carbon dioxide above normal levels to predict future rates of photosynthesis and plant growth

Pigment Molecules

Specific molecules in photosynthetic organisms that absorb light at specific frequencies to create energised electrons

Carbon Dioxide

Main source of carbon used in photosynthesis, influencing reaction rates until enzymes are saturated

Light Intensity

Determines the activation of photosynthetic pigments and influences rates of photosynthesis

Enzyme Factors

Temperature and pH affecting the functionality of photosynthetic enzymes and influencing reaction rates

CO2 Enrichment

Increasing the amount of carbon dioxide above normal levels to predict future rates of photosynthesis and plant growth

Biomass

The total mass of organisms in a given area or volume, used as an indirect measure of photosynthesis

Free Air CO2 Enrichment (FACE)

Experimental method using CO2-emitting pipes in open systems

Photosystems

Arrays of pigment molecules generating excited electrons

Photosystem I

Photosystem absorbing longer light wavelengths (~700 nm)

Photosystem II

Photosystem absorbing shorter light wavelengths (~680 nm)

Structured Array of Pigment Molecules

Maximizes light absorption and energy transfer in photosystems

Thylakoids

Membrane discs where light-dependent reactions occur

Triose Phosphate

Produced from G-3-P using NADPH and ATP

Regeneration of RuBP

Recombining TP molecules to regenerate RuBP in Calvin cycle

Chemiosmosis

Process of ATP synthesis using proton motive force

Cyclic Photophosphorylation

ATP generation using only Photosystem I

Non-Cyclic Photophosphorylation

ATP and NADPH generation using both photosystems

Light-Dependent Reactions

Convert light energy to chemical energy in photosynthesis

Light Independent Reactions

Use chemical energy to fix carbon and produce organic compounds

Carbon Fixation

Attachment of CO2 to RuBP by Rubisco in Calvin cycle

Reduction of NADP

Process of reducing NADP to form NADPH in photosystem I

Oxygenic Photosynthesis

Process of generating oxygen from water in photosystem II

Z Scheme

Representation of redox reactions in photosystems

ATP Synthase

Enzyme catalyzing ATP synthesis in thylakoids

Chemical Energy

Energy derived from light absorbed in photosystems

Photosynthetic Pigments

Molecules grouped into photosystems for light absorption

Hydrolysis

Process providing energy for reactions by breaking down ATP

Electron Transport Chain

Series of carrier proteins transferring energized electrons

Proton Motive Force

Electrochemical gradient used for ATP synthesis

Banded Iron Formations (BIFs)

Oceanic deposits resulting from iron and oxygen reaction

Cytosol

Fluid portion of the cytoplasm where metabolic reactions occur

Aerobic Respiration

Cellular process using oxygen to produce energy from glucose

Ozone Layer

Protective layer in the atmosphere shielding from harmful radiation