Ch. 8 - Photosynthesis Flashcards
regions on the surface of the Earth and in the atmosphere where living organisms exist
Biosphere
must consume food to sustain life
Heterotrophs
sustain themselves by producing organic molecules from inorganic sources such as CO2 and H2O
Autotrophs
autotrophs that use light as a source of energy to make organic molecules
Photoautotrophs
organelles found in plants and algal cells that carry out photosynthesis
Chloroplasts
pigment that gives plants their green color
Chlorophyll
tissue in the internal part of the leaf contains cells with chloroplasts; must receive light, H2O, and CO2
Mesophyll
pores where CO2 enters and O2 exits
Stomata
third membrane that contains pigment molecules
Thylakoid membrane
flattened, fluid-filled tubules in the thylakoid membrane
Thylakoids
a single compartment that is enclosed by thylakoids
Thylakoid lumen
a structure where thylakoids stack on top of each other
Granum
fluid-filled region of the chloroplast between the thylakoid membrane and the inner membrane
Stroma
distance between the peaks in a wave pattern
Wavelength
wavelengths from 380 nm to 740 nm
Visible Light
discrete particles between the peaks in a wave pattern
Photons
another type of pigment found in chloroplast; yellow to orange to red
Carotenoids
graph that plots a pigments light absorption as a function of the light’s wavelength
Absorption spectrum
plots the rate of photosynthesis as a function of the wavelength of light
Active spectrum
found in thylakoid membrane; composed of several dozen pigment molecules that are anchored to transmembrane proteins; directly absorb photons of light
Light harvesting complex
quickly remove the high energy electron from P680* and transfer it to another molecule, where the electron is stable; replace the electron that is removed when P680* becomes P680+ (replaced with low-energy electron from water)
Reaction Center
primary electron acceptor
Pheophytin
model that shows an electron proceeding through a series of energy changes during photosynthesis
Z scheme
Where does the Calvin Cycle occur in plants and algae?
stroma of chloroplasts
Where does the Calvin Cycle occur in plants and algae?
cytoplasm
stage 1; CO2 is incorporated into RuBP, a five-carbon sugar
Carbon Fixation
6-carbon intermediate that immediately splits in half to form 2 molecules of 3-phosphoglycerate
product of carbon fixation
enzyme that catalyzes the steps in carbon fixation
rubisco
ATP is used to convert 3PG to 1,3-biphosphoglycerate; electron from NADPH reduces 1,3-BPG to glyceraldehyde-3-phosphate (G3P); 12 G3P molecules are made at the end of phase 2 and only 2 of these G3P molecules are used in carbohydrate production
Reduction and Carbohydrate Production
converts the 10 G3P molecules into 6 RuBP molecules, using 6 molecules of ATP; after the RuBP molecules have been regenerated they serve as acceptors for CO2, thereby allowing the cycle to continue
Regeneration of RuBP
the incorporation of CO2 into 3PG via RuBP is the only way for carbon fixation to occur; ~85% of the plant species on Earth
C3 Plants
uses O2 and liberates CO2
Photorespiration
first product of carbon fixation is a molecule with 4 carbon atoms
C4 Plants
molecule with four carbon atoms; can avoid photorespiration
Oxaloacetate
ex. cacti, bromeliads, and sedums; to avoid water loss, they keep their stomata closed during the day and open at night
CAM Plants
