AP Bio Exam study guide chapter 10

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Terms in this set (...)

photosynthesis
A process used by plants and other autotrophs to capture light and energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates, such as sugars and starches
autotroph
An organism that is able to capture energy from sunlight or chemicals and use it to produce its own food
heterotroph
An organism that cannot make its own food and gets food by consuming other living things
chloroplast
An organelle found in plant and algae cells where photosynthesis occurs
mesophyll
Spongy tissue in the interior of the leaf where most chloroplasts are found.
guard cell
Pairs of cells that surround stomata and control their opening and closing
stroma
Fluid inside the chloroplast where the Calvin Cycle happens
thylakoid
A flattened membrane sac inside the chloroplast, used to convert light energy into chemical energy
stomata
Small openings on the underside of a leaf through which oxygen and carbon dioxide can move
grana
stacks of thylakoids
oxygen
byproduct of light reactions (from splitting of water)
glucose
product of photosynthesis
cuticle
The waxy, waterproof layer that covers the leaves and stems of most plants
photosynthesis equation
redox reaction
A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction
light reactions
The first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process.
Calvin cycle
reactions of photosynthesis in which ATP and NADPH are used to build high-energy compounds such as sugars
dark reactions
another name for the Calvin cycle
light-independent reactions
another name for the Calvin cycle
NADP+
An electron acceptor that temporarily stores energized electrons produced during the light reactions
NADPH
An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADP+, forming NADPH, which provides the high-energy electrons for the reduction of carbon dioxide to sugar in the Calvin cycle.
phosphorylation
addition of a phosphate group
carbon fixation
The initial incorporation of carbon into organic compounds (first stage of Calvin cycle)
3 stages of Calvin cycle
fixation, reduction, regeneration
ATP
energy source for Calvin cycle, used to form sugar from CO2
wavelength
The distance between crests of waves, such as those of the electromagnetic spectrum.
electromagnetic spectrum
All of the frequencies or wavelengths of electromagnetic radiation
visible light
Electromagnetic radiation that can be seen with the unaided eye
pigment
substance that absorbs visible light, producing color
chlorophyll
Green pigment in plants that absorbs light energy used to carry out photosynthesis
chlorophyll a
A photosynthetic pigment that participates directly in the light reactions
chlorophyll b
One type of chlorophyll that acts as an antenna pigment, expanding the wavelengths of light that can be used to power photosynthesis
photosystem
A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes. There are two types of photosystems, I and II; they absorb light best at different wavelengths.
reaction-center complex
an organized association of proteins holding a special pair of chlorophyll a molecules
light-harvesting complex
A complex of proteins associated with pigment molecules (including chlorophyll a, chlorophyll b, and carotenoids) that captures light energy and transfers it to reaction-center pigments in a photosystem.
photosystem II
A photosystem that contains a pair of P680 chlorophyll molecules and uses absorbed light energy to split water into protons and oxygen and to produce ATP.
photosystem I
A photosystem that contains a pair of P700 chlorophyll molecules and uses absorbed light energy to split water into protons and oxygen and to produce ATP.
chemiosmosis
A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.
rubisco
nickname for RuBP carboxylase, enzyme that catalyzes first step of Calvin cycle (addition of CO2 to RuBP)
RuBP
The 5-carbon molecule that accepts CO2 at the beginning of the Calvin cycle
G3P
Three-carbon sugar that is the main product of the Calvin cycle
Two of these combine to form glucose
After 3 turns of the Calvin cycle, 1 of these leaves the cycle and 5 are used to regenerate RuBP
glyceraldehyde-3-phosphate
full name of G3P
C3 plant
(95% of plants)
These only use the Calvin cycle (unlike C4/CAM)
Best climate: cool, damp, cloudy
Loss of carbon through photorespiration is high, but they require less light because metabolic process is efficient
photorespiration
A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide
C4 plant
A plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle
bundle-sheath cell
Cells tightly wrapped around the veins of a leave (the site of the Calvin cycle in C4 plants)
mesophyll cell
A loosely arranged photosynthetic cell located between the bundle sheath and the leaf surface (the site of carbon fixation in C4 plants)
crassulacean acid metabolism
full name of CAM
CAM plant
A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions. In this process, carbon dioxide entering open stomata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day, when stomata are closed.
light independent reactions
step of photosynthesis in which glucose is formed
ADP and NADP+
byproducts of reduction phase of Calvin cycle
go on to participate in light reactions
three reactants in synthesis of 1 glucose molecule (6 turns of Calvin cycle)
6 CO2
18 ATP
12 NADPH
causes of photorespiration
buildup of oxygen in leaf because plants close stomata to prevent water loss in hot temperatures
rubisco's higher affinity for oxygen at higher temperatures
pyruvate
phosphorylated to regenerate PEP in C4 pathway
Input and output of light reactions.
Inputs: 6H2O, 6CO2, (light) energy Outputs: C6H12O6 (glucose), 6O2
Input and output of calvin cycle.
Input molecules are carbon dioxide, ATP, and NADPH. The output molecules are sugar, ADP, NADP+, and inorganic phosphate (Pi).
Where does the calvin cycle take place?
In the stroma of chloroplast in photosynthetic organisms.
How many cycles must the Calvin Cycle complete to make one molecule of G3P?
Three turns of the Calvin cycle are needed to make one G3P molecule that can exit the cycle and go towards making glucose.