Bio Ch 7 Flashcards
Photosynthesis
converts solar energy into the chemical energy of a carbohydrate
Autotrophs
land plants, algae, and cyanobacteria are these because they produce their own food
Heterotrophs
consumers; take in preformed organic molecules
Stomata (singular = stoma)
carbon dioxide in the air enters a leaf through these small openings
Chloroplasts
organelles that carry on photosynthesis
Stroma
semifluid interior of the chloroplast
Thylakoids
flattened sacs within the stroma of chloroplasts
Grana (singular = granum)
stacks of thylakoids; looked like piles of seeds to early microscopists
Chlorophyll
within the thylakoid membrane are this and other pigments that are capable of absorbing solar energy, the type of energy that drives photosynthesis
Light reactions
only occur when solar energy is available (during daytime hours)
Calvin Cycle Reactions
named for Melvin Calvin (discoverer); enzymatic reactions that reduce carbon dioxide to a carbohydrate in the stroma of chloroplasts
Absorption spectrum
pigments in chloroplasts are capable of absorbing various portions of visible light
Carotenoids
yellows/oranges; able to absorb light in the violet-blue-green range
Photosystem
consists of a pigment complex (molecules of chlorophyll a, chlorophyll b, & the carotenoids) & electron acceptor molecules within the thylakoid membrane
Noncyclic pathway
during light reactions, electrons usually follow this that begins with photosystem I
Electron Transport Chain (ETC)
series of carriers that pass electrons from electron acceptor to reaction center
ATP Synthase Complex
has a channel and a protruding ATP synthase; enzyme that joins ADP & P
Chemiosmosis
method of producing ATP because ATP productions is tied to the establishment of an H+ gradient
Climate change
expected rise in the average global temperature during the 21st century due to the introduction of certain gases into the atmosphere
Carbon dioxide fixation
first step of the Calvin Cycle; molecule of carbon dioxide from the atmosphere is attached to RuBP, a 5-carbon molecule; result = two 3-carbon molecules
RuBP carboxylase
protein that makes up about 20-50% of the protein content in chloroplasts
C3 Plants
majority of land plants (ex. azaleas, maples, tulips); use the enzyme RuBP carboxylase to fix CO2 to RuBP in mesophyll cells
Photorespiration
in the presence of light, oxygen is taken up and CO2 is released
C4 Plants
fix CO2 to PEP (phosphoenolpyruvate, a C3 molecule) using the enzyme PEP carboxylase (PEPCase); result = oxaloacetate (C4 molecule); examples: sugarcane, corn, Bermuda grass
CAM
crassulacean-acid metabolism; form of photosynthesis in succulent plants that separates the light-dependent and Calvin reactions by time
