Photosynthesis test

Enzyme

A catalytic protein that speeds up reactions.

Catalyst

Chemical agent speeding up reactions without consumption.

Activation Energy

Energy required to reach the transition state.

Transition State

High-energy state during a chemical reaction.

Exergonic Reaction

Reaction with a negative ΔG, releasing energy.

Endergonic Reaction

Reaction with a positive ΔG, absorbing energy.

Substrate

Reactant that an enzyme acts on.

Active Site

Region on enzyme where substrate binds.

Induced Fit

Enzyme shape change to fit substrate.

Lock and Key Model

Substrate fits into active site like a key.

Enzyme-Substrate Complex

Temporary complex formed during catalysis.

Denaturation

Loss of enzyme shape, reducing activity.

Optimal Conditions

Environmental factors favoring enzyme activity.

Cofactors

Non-protein helpers for enzyme activity.

Coenzymes

Organic molecules aiding enzyme function.

Competitive Inhibitors

Bind active site, competing with substrates.

Noncompetitive Inhibitors

Bind elsewhere, altering enzyme shape.

Allosteric Regulation

Binding at sites altering enzyme activity.

ATP

Substrate for enzymes in anabolic reactions.

ADP and Pi

Substrates for enzymes in catabolic reactions.

Environmental Factors

Temperature and pH affecting enzyme activity.

Enzyme Concentration

Amount of enzyme influencing reaction rate.

Regulatory Molecule

Binds to enzyme, affecting its function remotely.

Enzyme Activity Regulation

Controls metabolism and manages energy needs in cells.

Metabolic Pathways

Series of chemical reactions managed by multiple enzymes.

Feedback Inhibition

End product of pathway shuts down the pathway.

Chemical Resource Efficiency

Prevents waste by regulating product synthesis.

Substrate Concentration

Higher substrate than enzyme leads to reaction rate stabilization.

Photosynthesis

Biochemical reactions converting CO2 and water into carbohydrates.

Autotrophs

Organisms that produce organic molecules from CO2.

Heterotrophs

Organisms that obtain organic material from other organisms.

Phytoplankton

Unicellular organisms responsible for oceanic photosynthesis.

Chloroplasts

Cell organelles where photosynthesis occurs in plants.

Stomata

Microscopic pores for gas exchange in leaves.

Thylakoids

Membranes in chloroplasts where chlorophyll is located.

Grana

Stacked columns of thylakoids in chloroplasts.

Stroma

Dense fluid inside chloroplasts, site of reactions.

Anabolic Process

Builds complex molecules using energy, like photosynthesis.

Redox Reactions

Transfer of electrons and energy in chemical reactions.

Oxidation

Loss of electrons and energy in a reaction.

Reduction

Gain of electrons and energy in a reaction.

Water Splitting

Chloroplasts split H2O, releasing oxygen as by-product.

Endergonic Process

Requires energy input, as in photosynthesis.

Two Stages of Photosynthesis

Photosynthesis occurs in light-dependent and light-independent reactions.

Light Reactions

Convert solar energy to chemical energy.

Calvin Cycle

Forms sugar from CO2 using ATP and NADPH.

Thylakoid Membranes

Location of light reactions in chloroplasts.

Stroma

Site of the Calvin cycle in chloroplasts.

Chlorophyll

Main pigment absorbing visible light in plants.

Photophosphorylation

ATP generation from ADP and P using light.

NADP+

Electron acceptor reduced to NADPH in light reactions.

NADPH

Reduced form of NADP+, carries electrons.

Water Splitting

Releases O2 and provides electrons for photosynthesis.

Electromagnetic Spectrum

Range of all types of electromagnetic radiation.

Visible Light

Portion of the spectrum visible to human eyes.

Photons

Discrete particles of light with fixed energy.

Absorption Spectrum

Graph of pigment light absorption versus wavelength.

Action Spectrum

Effectiveness of different wavelengths in photosynthesis.

Excited State

Higher energy state of an electron after light absorption.

Ground State

Stable energy state of an electron in chlorophyll.

Chlorophyll a

Primary pigment for photosynthesis, absorbs violet-blue and red.

Chlorophyll b

Accessory pigment, assists chlorophyll a in light absorption.

Carotenoids

Pigments that reflect yellow and orange light.

Photosynthetic Electron Transport Chain

Series of redox reactions transferring electrons.

Carbon Fixation

Incorporation of CO2 into organic molecules.

Photons Absorption

Only specific energy photons are absorbed by pigments.

Photosystem

Complex of proteins and pigments absorbing light energy.

Photosystem II (PSII)

First photosystem in the electron transport chain.

Photosystem I (PSI)

Second photosystem in the electron transport chain.

Electron Transport Chain

Series of proteins transferring electrons in photosynthesis.

Photon

Light particle absorbed by pigments in photosystems.

Thylakoid Membrane

Site of photosystems and electron transport in chloroplasts.

Water Splitting

Process generating electrons and oxygen in PSII.

Oxygen Production

By-product of water splitting in photosynthesis.

Proton Gradient

Difference in proton concentration across thylakoid membrane.

ATP Synthase

Enzyme synthesizing ATP using proton gradient energy.

Photophosphorylation

ATP production linked to light energy absorption.

Calvin Cycle

Pathway using ATP and NADPH to synthesize carbohydrates.

Rubisco

Enzyme catalyzing CO2 fixation in Calvin cycle.

Triose Phosphate

Carbohydrate produced during the Calvin cycle.

Starch Formation

Storage of carbohydrates in chloroplasts.

Reactive Oxygen Species

Potentially harmful molecules formed from excess light energy.

Xanthophyll Pigments

Pigments dissipating excess light energy as heat.

Carbon Fixation

Conversion of CO2 into organic compounds in Calvin cycle.

Glyceraldehyde 3-Phosphate (G3P)

3-carbon sugar produced in the Calvin cycle.

NADP Reductase

Enzyme reducing NADP+ to NADPH in PSI.

Chemiosmosis

Process of ATP synthesis driven by proton movement.

NADPH

Electron carrier used in Calvin cycle reactions.

Light Reactions

Initial phase of photosynthesis producing ATP and NADPH.