Key Terms
Photoautotrophs
Plants, algae, cyanobacteria
Heterotrophs
Animals, fungi, most bacteria
Chemoautotrophs
Certain bacteria (deep sea vents)
Mesophyll
Middle layer of leaf cells; where photosynthesis happens
Stomata (singular
Stoma): pores on the underside of leaves; regulate CO2 entry and O2 exit; also control water loss Guard cells: flank eac
Chloroplast
Organelle where photosynthesis takes place in eukaryotes
Wavelength
Distance between two consecutive crests (or troughs) of a wave
Photon
A discrete packet (quantum) of light energy
Pigment
Molecule that absorbs certain wavelengths and reflects others; its color is what it reflects, not what it absorbs
Absorption spectrum
Unique pattern of wavelengths absorbed by a specific pigment Antenna pigment: absorbs light; passes energy to reaction c
Photosystem
Protein-pigment complex embedded in the thylakoid membrane; converts light into chemical energy
Function
1. Transfers electrons from PSII to PSI 2.
Location
Stroma Inputs per cycle turn: 1 CO2, 1 RuBP, ATP, NADPH Key enzyme: RuBisCO
Photosynthesis
CO2 + H2O + light --> carbohydrates + O2 Cellular respiration: carbohydrates + O2 --> CO2 + H2O + ATP
Carotenoid
Yellow-orange-red pigment; absorbs excess energy; releases it as heat Chemoautotroph: makes food from inorganic chemical