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46 Cards in this Set
- Front
- Back
define heterotroph
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Must eat food, organic molecules from their environment, to sustain life
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define autotroph
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Make organic molecules from inorganic sources
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define photoautotroph
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Uses light as a source of energy
--Green plants, algae, cyanobacteria |
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name the photosynthesis substrates
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light, carbon dioxide, and water
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name the photosynthesis end products
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sugar (C6H12O6) and gives off oxygen and water
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describe photosynthesis
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CO2 + H2O + light energy → C6H12O6 + O2 + H2O
~CO2 is reduced, H2O is oxidized ~~Energy from light drives this endergonic reaction |
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define chlorophlasts
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Double membrane bound organelles in plants and algae that carry out photosynthesis
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define chlorophyll
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pigment that gives plants green color
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define central mesophyll
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• Majority of photosynthesis occurs in leaves in central mesophyll (which is where the chloroplasts are), but can happen anywhere the plant is green
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define stomata
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pores where carbon dioxide enters and oxygen exits leaf
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define thylakoid membrane
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third membrane containing pigment molecules (including chlorophyll)
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contrast thylakoid, thylakoid lumen, and granum
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-Flattened, fluid-filled disk is called a thylakoid
-Thylakoids enclose a compartment called the thylakoid lumen -Stack of thylakoids form a granum |
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define stroma
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fluid-filled region inside the chloroplast between thylakoid membrane and inner membrane
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where do light reactions occur?
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thylakoid
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substrates of the light reactions?
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water, light energy
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products of light reactions?
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O2, ATP, NADPH
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where do dark reactions (Calvin cycle) occur?
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stroma
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substrates of calvin cycle?
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CO2, ATP, NADPH
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product of calvin cycle?
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glucose (or general carbs)
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define chlorophyll a
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blue-green pigment (reflect blue-green) and is the “primary photosynthetic pigment.”
-Primary electron acceptor (when electron gets excited). |
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define chlorophyll b
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reflects yellow-green spectrum of light and is a secondary electron acceptor (therefore still participating in photosynthesis).
-Kind of like a backup that increases the wavelength of light that will help generate photosynthesis |
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define carotenoids
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-group of accessary pigments that are yellow-orange and sometimes red.
-In the spring and summer, the carotenoids act as a sunscreen for the plant (to prevent burn spots). -Don’t participate in photosynthesis; more of a protective pigment. |
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describe photosystem I
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-generates ATP
1.Light-harvesting complex ---Directly absorbs photons 2. Reaction center ---Transfered to primary electron acceptor |
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describe photosystem II
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-generates NADPH
-Light striking light-harvesting complex of PSI transfers energy to a reaction center |
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describe noncyclic electron flow
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-Linear process produces ATP and NADPH in equal amounts
-light reactions=noncyclic -Electrons come from water |
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define cyclic photophosphorylation
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path of electrons is cyclic, light energizes the electrons, and ATP is made via the phosphorylation of ADP
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what environmental conditions can influence the efficiency and the way calvin cycle works?
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light intensity, temperature, water availability
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define C3 plants
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plants that use Calvin cycle = more efficient at producing sugar
-In cooler climates, C3 plants use less energy to fix CO2 -90% of plants are C3 |
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define C4 plants
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plants that don’t use the Calvin cycle = more efficient at conserving water
-Make a 4 carbon compound in the first step of carbon fixation -In warm dry climates C4 plants have the advantage in conserving water and preventing photorespiration |
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define CAM plants
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plants were photosynthesis occurs directly within mesophyll cells
-open stomata at night, closed during day to conserve water |
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T/F: Chloroplasts are the organelles responsible for carrying out photosynthesis in plants and algae.
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True
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The addition of an oxygen molecule to ribulose bisphosphate (RuBP) resulting in phosphoglycolate is most accurately referred to as...
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photorespiration.
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Organisms which synthesize organic molecules from inorganic sources using light energy are most accurately referred to as ________, while organisms which must consume organic molecules from their environments to survive are most accurately referred to as ________.
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photoautotrophs; heterotrophs
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Calvin cycle reactions occur in the ________, while light reactions occur in the ________.
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stroma; thylakoid membranes
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When an electron absorbs energy and exists in an excited state, the electron can...
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drop back down to its original energy level and release light, be removed from one molecule and transferred to a different molecule, and drop back down to its original energy level and release heat.
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Which of the following statements regarding cyclic electron flow is incorrect?
A) Cyclic electron flow is favored when NADPH levels are high B) ATP is produced via an electrochemical gradient C) High energy electrons are transferred to QB via ferredoxin D) Cyclic electron flow results in high levels of NADPH E) ATP is the final product of cyclic electron flow |
D) Cyclic electron flow results in high levels of NADPH
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True or False: The absorption of light in photosystem II results in an electron with a higher energy level than was attained in photosystem I.
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False
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The production of 1 G3P molecule requires
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6 ATP : 9 NADPH and 3CO2
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The most common storage form of carbohydrate in chloroplasts is...
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starch
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C4 plants are particularly suited for conditions of high temperatures and intense sunlight due to...
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the physical separation of mesophyll cells and bundle sheath cells.
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Water necessary for photosynthesis...
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provides electrons to replace lost electrons in photosystem II
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Cyclic electron flow that occurs in photosystem I produces...
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ATP
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During the first phase of the Calvin cycle, CO2 is incorporated into ribulose biphosphate by..
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rubisco
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The NADPH produced during light reactions is nesc. for...
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the reduction phase which produces carbohydrates in the Calvin cycle
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The majority of the G3P produced during reduction and carb production phase is used to produce...
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RuBP
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Plants commonly found in hot and dry enviornments that carry out carbon fixation at night are...
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CAM plants
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