Chapter 5 - Photosynthesis

Vocabulary flashcards covering key terms and concepts from BIOL 100 Chapter 5 on photosynthesis, including structures, reactions, pigments, energy carriers, and variations of the photosynthetic process.

Photosynthesis

Process by which producers convert light energy, H2O, and CO2 into glucose and O2.

General Equation of Photosynthesis

6 CO2 + 6 H2O + light → C6H12O6 + 6 O2.

Reactants (Photosynthesis)

Carbon dioxide, water, and light energy.

Products (Photosynthesis)

Glucose and oxygen.

Producer

Organism (plant, algae, some bacteria) that makes its own food through photosynthesis.

Consumer

Organism that obtains energy by eating producers or other consumers.

Decomposer

Organism that breaks down dead matter, relying indirectly on producers for energy.

Mesophyll

Leaf tissue layer where photosynthesis mainly occurs.

Stomata

Pores in leaves that allow CO2 in and O2 out for gas exchange.

Chloroplast

Organelle where photosynthesis takes place in plants and algae.

Thylakoid

Membranous sac inside chloroplast; site of light-dependent reactions and chlorophyll.

Granum

Stack of thylakoids within a chloroplast.

Stroma

Fluid-filled space surrounding grana; site of the Calvin Cycle.

Chlorophyll

Primary light-absorbing pigment in photosynthetic organisms.

Chlorophyll A

Main pigment; absorbs violet-blue and red light.

Chlorophyll B

Accessory pigment; absorbs blue and red-orange light.

Accessory Pigments

Molecules that broaden the spectrum of light a plant can use for photosynthesis.

Light-Dependent Reactions

Stage in thylakoids that uses light to produce ATP, NADPH, and O2.

Light-Independent Reactions

Calvin Cycle in stroma that uses ATP and NADPH to fix CO2 into glucose.

Photosystem I

Protein-pigment complex in thylakoid membrane; part of electron transport chain.

Photosystem II

Protein-pigment complex that initiates the light reactions by splitting water.

Electron Transport Chain (Photosynthesis)

Series of proteins that transfer excited electrons, generating ATP and NADPH.

ATP

Primary cellular energy currency produced during light reactions.

NADPH

Electron carrier produced in light reactions; provides reducing power for Calvin Cycle.

Calvin Cycle

Light-independent pathway that fixes CO2 into G3P using ATP and NADPH.

Carbon Fixation

First Calvin Cycle phase where RuBisCO attaches CO2 to RuBP forming 3-PGA.

RuBisCO

Key enzyme that catalyzes CO2 fixation in the Calvin Cycle.

RuBP (Ribulose-1,5-bisphosphate)

Five-carbon sugar that accepts CO2 in the Calvin Cycle.

3-PGA (3-phosphoglycerate)

First stable three-carbon compound produced after CO2 fixation.

Reduction (Calvin Cycle)

Phase that converts 3-PGA into G3P using ATP and NADPH.

G3P (Glyceraldehyde-3-phosphate)

Three-carbon sugar; some exits cycle to become glucose.

Regeneration (Calvin Cycle)

Phase where remaining G3P regenerates RuBP to continue the cycle.

C3 Photosynthesis

Most common pathway producing 3-PGA; favored in cool, wet environments.

C4 Photosynthesis

Pathway with spatial separation of CO2 fixation; adapted to hot, sunny climates.

CAM Photosynthesis

Pathway with temporal separation of CO2 fixation (night/day); suited for dry areas.