Photosynthesis: Energy Conversion and Carbon Fixation

Photosynthesis

Process converting sunlight into chemical energy.

Autotrophic Nutrition

Self-feeding mode using inorganic materials for energy.

Endosymbiont Theory

Theory explaining chloroplast origin from prokaryotes.

Photosynthetic Equation

Chemical equation summarizing photosynthesis process.

Splitting of Water

Process where water is divided into hydrogen and oxygen.

ATP

Energy currency produced during light reactions.

Electron Transport Chain

Series of proteins transferring electrons in respiration.

Magnesium Atom

Central atom in the porphyrin ring of chlorophyll.

Chloroplast

Organelle where photosynthesis occurs in plant cells.

Photosystem II

First photosystem involved in light reactions.

Photosystem I

Second photosystem that generates NADPH.

O2

Gas that can inhibit photosynthesis in plants.

Mitochondria

Cell organelles generating ATP from respiration.

Photosynthetic Adaptation

Evolutionary changes enhancing photosynthesis efficiency.

Heterotrophic Nutrition

Dependent on other organisms for food.

Autotrophs

Organisms producing organic compounds from inorganic sources.

Photoautotrophs

Organisms using light to synthesize organic substances.

Producers

Organisms that generate organic compounds in ecosystems.

Chloroplasts

Organelles where photosynthesis occurs in plants.

Mesophyll

Leaf tissue containing chloroplasts for photosynthesis.

Stomata

Microscopic pores for gas exchange in leaves.

Thylakoids

Membrane sacs in chloroplasts where light reactions occur.

Grana

Stacks of thylakoids in chloroplasts.

Stroma

Dense fluid in chloroplasts surrounding thylakoids.

Chlorophyll

Green pigment that absorbs light for photosynthesis.

Cyanobacteria

Photosynthetic prokaryotes contributing to oxygen production.

Decomposers

Organisms breaking down dead matter for nutrients.

Fossil Fuels

Energy stores from ancient organic remains.

Glucose

Main product of photosynthesis used for energy.

Light Reactions

Initial phase of photosynthesis converting light energy.

Calvin Cycle

Phase of photosynthesis synthesizing sugars from CO2.

Organic Molecules

Compounds containing carbon, produced during photosynthesis.

Carbon Dioxide

Gas absorbed by plants during photosynthesis.

Water

Essential reactant in photosynthesis, produced and consumed.

Oxygen

By-product of photosynthesis released into the atmosphere.

Veins

Structures transporting water and sugars in plants.

Euglena

Unicellular protist capable of photosynthesis.

Kelp

Multicellular algae that are photoautotrophs.

Photosynthesis Equation

Simplified representation of photosynthesis process.

Carbohydrate Formula

General formula for sugars, represented as CxHy.

C. B. van Niel

Scientist who proposed water as oxygen source.

Hydrogen Sulfide

Alternative source used by some bacteria for photosynthesis.

Oxygen Production

Oxygen released during photosynthesis comes from water.

Redox Reactions

Reactions involving electron transfer during photosynthesis.

Endergonic Process

Process requiring energy input, like photosynthesis.

Thylakoid

Membrane structures where light reactions occur.

NADP+

Electron acceptor in light reactions, forming NADPH.

Photophosphorylation

Process of adding phosphate to ADP using light energy.

Carbon Fixation

Initial incorporation of CO2 into organic molecules.

NADPH

Reducing power generated in light reactions.

Light-Independent Reactions

Calvin cycle steps that do not directly require light.

Chemical Energy

Energy stored in chemical bonds, produced in photosynthesis.

Waste Products

Oxygen released as a by-product of photosynthesis.

Hydrogen Ions

Protons released during water splitting in light reactions.

Solar Energy

Energy from sunlight utilized in photosynthesis.

Chemical Factories

Chloroplasts convert light energy into chemical energy.

Reducing Power

Ability to donate electrons, provided by NADPH.

Glucose Formation

Result of six carbon incorporations in Calvin cycle.

Thylakoid Membranes

Sites of light reactions in chloroplasts.

Melvin Calvin

Scientist who elucidated steps of the Calvin cycle.

Electromagnetic energy

Energy traveling in rhythmic waves through fields.

Wavelength

Distance between crests of electromagnetic waves.

Electromagnetic spectrum

Range of all electromagnetic radiation types.

Visible light

Narrow band of wavelengths detectable by humans.

White light

Mixture of all wavelengths of visible light.

Prism

Device that separates white light into colors.

Photons

Discrete particles of light with fixed energy.

Energy-wavelength relationship

Shorter wavelengths have greater photon energy.

Pigments

Substances that absorb specific wavelengths of light.

Spectrophotometer

Instrument measuring light absorption by pigments.

Absorption spectrum

Graph showing pigment absorption versus wavelength.

Accessory pigments

Pigments aiding photosynthesis, e.g., chlorophyll b.

Carotenoids

Accessory pigments that absorb light between 400-520 nm.

Action spectrum

Graph of photosynthesis rate versus light wavelength.

Theodor W. Engelmann

Botanist who demonstrated action spectrum in 1883.

Aerobic bacteria

Organisms congregating near oxygen sources from photosynthesis.

Photosynthetic rate

Measured by oxygen release during photosynthesis.

Chlorophyll a

Main pigment participating directly in light reactions.

Chlorophyll b

Accessory pigment assisting chlorophyll a in photosynthesis.

Light absorption

Process where pigments capture specific wavelengths.

Transmittance

Fraction of light passing through a sample.

Galvanometer

Device measuring electric current from light energy.

Violet-blue light

Most effective wavelength for driving photosynthesis.

Red light

Second most effective wavelength for photosynthesis.

Green light

Least effective wavelength for photosynthesis.

Light energy conversion

Process of transforming light into chemical energy.

Light wavelength range

Visible light spans from 380 to 750 nanometers.

Engelmann's Experiment

Demonstrated bacteria concentration in light wavelengths.

Action Spectrum

Shows effective wavelengths for photosynthesis.

Absorption Spectrum

Reflects light wavelengths absorbed by chlorophyll.

Chlorophyll c

Absorbs higher wavelengths, aiding shaded photosynthesis.

Chlorophyll f

Absorbs far-red light, enabling survival in low light.

Photoprotection

Prevents damage from excessive light energy.

Excited State

Higher energy state of an electron after photon absorption.

Ground State

Normal energy state of a pigment molecule.

Fluorescence

Emission of light by chlorophyll after photon absorption.

Photosystem

Complex of chlorophyll and proteins for light harvesting.

Reaction-Center Complex

Contains chlorophyll pairs and primary electron acceptor.

Light-Harvesting Complex

Surrounds reaction-center, contains various pigment molecules.

Thylakoid Membrane

Site of photosystems in chloroplasts.