Chapter 5 – Photosynthesis Vocabulary

A set of vocabulary flashcards covering key terms and concepts from Chapter 5 on photosynthesis.

Photosynthesis

Process that converts sunlight, water, and carbon dioxide into carbohydrates (usually glucose) and releases oxygen

Autotroph

Organism able to manufacture its own food

Photoautotroph

Autotroph that uses sunlight and carbon dioxide to synthesize carbohydrates

Heterotroph

Organism that must obtain energy and carbon by consuming other organisms

Mesophyll

Middle layer of a leaf where most photosynthesis occurs

Stomata

Small regulated pores in leaves for gas exchange of CO₂ and O₂

Chloroplast

Photosynthetic organelle with inner, outer, and thylakoid membranes

Thylakoid

Flattened, disc-shaped membrane sac inside chloroplasts that contains chlorophyll

Thylakoid Membrane

Site of the light-dependent reactions

Chlorophyll a

Primary green pigment that absorbs blue and red light

Chlorophyll b

Accessory pigment that absorbs blue and red-orange light

Carotenoids

Accessory pigments that absorb additional light wavelengths and protect chlorophyll

Photosystem

Cluster of pigments and proteins in a thylakoid that initiates light-dependent reactions

Photosystem II

First functioning photosystem; passes excited electrons to the electron transport chain

Electron Transport Chain (ETC)

Series of proteins that moves electrons and pumps H⁺ ions to build a gradient

Light-Dependent Reactions

First stage of photosynthesis that uses light energy to produce ATP, NADPH, and O₂

Calvin Cycle

Second stage of photosynthesis in the stroma that fixes CO₂ and synthesizes sugars

Stroma

Fluid surrounding thylakoids where the Calvin cycle occurs

Wavelength

Distance between successive wave crests; inversely related to energy

Electromagnetic Spectrum

Entire range of electromagnetic radiation wavelengths

Absorption Spectrum

Specific pattern of light wavelengths absorbed by a pigment

Photon

Individual packet of light energy absorbed by pigments

RuBisCO

Enzyme that catalyzes the fixation of CO₂ to RuBP in the Calvin cycle

Ribulose Bisphosphate (RuBP)

Five-carbon molecule that reacts with CO₂ in carbon fixation

Carbon Fixation

First phase of the Calvin cycle where CO₂ is attached to RuBP

Reduction (Calvin Cycle)

Phase of the Calvin cycle that uses ATP and NADPH to produce G3P sugars

Regeneration (Calvin Cycle)

Phase of the Calvin cycle that reforms RuBP to continue the cycle

Hydrolysis of Water

Splitting of H₂O during light-dependent reactions, releasing electrons, protons, and O₂