Midterm II -- Ch. 10 - Photosynthesis Flashcards
Metabolic Pathways
a series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule to simpler molecules (catabolic pathway).
Catabolic Pathway
a series of chemical reactions that break down a complex molecule into simpler molecules.
Anabolic Pathway
a series of chemical reactions that build a complex molecule.
Photosynthesis
the conversion of light energy to chemical energy that is stored in sugars or other organic compounds; occurs in plants, algae, and certain prokaryotes.
Autotrophs
“self-feeders” – don’t eat anything derived from other human beings.
Heterotrophs
live on compounds produced by other organisms.
Mesophyll
leaf cells specialized for photosynthesis.
Stomata
microscopic pores where CO2 enters and O2 leaves the plant.
Stroma
the dense fluid within the chloroplast surrounding the thylakoid membrane and containing ribosomes and DNA; involved in the synthesis of organic molecules from CO2 and H2O.
Thylakoid
a flattened membranous sac inside a chloroplast.
Chlorophyll
green pigment that gives plants their color.
Light reactions
convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process; 1st of two major stages in photosynthesis.
Calvin cycle
2nd of two major stages in photosynthesis; fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrates.
NADP+
an electron acceptor that, as NADPH, temporarily stores, energized electrons produced during the light reactions.
Photophosphorylation
process of generating ATP from ADP and phosphate by means of chemiosmosis.
Carbon fixation
initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism.
Wavelength
distance between the crests of electromagnetic waves.
Spectrometer
instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution.
cartenoid
accessory pigment in the chloroplasts of plants.
photosystem
light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes.
reaction-center complex
complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor.
light-harvesting complex
a complex of proteins associated w/ pigment molecules that captures light energy and transfers it to reaction-center pigments in a photosystem.
primary electron acceptor
a specialized molecule that share the reaction-center complex with a pair of chlorophyll a molecules and that accepts an electron from them.
photosystem II (PS II)
one of two light-capturing units in a chloroplast’s thylakoid membrane or in the membrane of some protists.
photosystem I (PS I)
light-capturing unit in a chloroplast’s thylakoid membrane or in the membrane of some protists.
linear electron flow
a route of electron flow during the light reactions of photosynthesis that involves both PS I and PS II and produces ATP, NADPH, and O2.
cyclic electron flow
a route of electron flow during the light reactions of photosynthesis that involves only PS I and produces ATP
glyceraldehyde 3-phosphate (G3P)
a 3-C carbohydrate that is the direct product of the calvin cycle.
rubisco
RuBP carboxylase, the enzyme that catalyzes the 1st step of the Calvin cycle.
C3 plants
plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a 3-C compound.
photorespiration
metabolic pathway that consumes O2 and ATP releases CO2, and decreases photosynthetic output.
bundle-sheeth cells
in C4 plants, type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
PEP carboxylase
enzyme that adds CO2 to PEP to form an oxaloacetate in mesophyll cells of C4 plants; acts prior to photosynthesis.
CAM
adaption for photosynthesis in arid conditions; plant takes up CO2 and incorporates it into a variety of organic acids at night.
