Flashcards in Photosynthesis Deck (107):
What does photosynthesis do?
Maintain oxygen levels in the atmosphere
What is the photosynthesis equation?
6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
What type of reaction is photosynthesis?
What are the products of photosynthesis?
Oxygen and glucose
What does photosynthesis use to create food molecules?
What is the relationship between Cellular Respiration and Photosynthesis?
The reactants for photosynthesis are the products for cellular respiration and the reactants for the cellular respiration are the products of photosynthesis.
Pigment that give a plant its green color and is used by the plant to complete the process of photosynthesis.
The gas that a plant released into the atmosphere as a product of the process of photosynthesis.
The gas that a plant takes in to use in the process of photosynthesis.
The part of the plant where most of the photosynthesis process occurs.
The part of the plant that supports the leaves and transports water through the plant.
Energy from the sun that is used by plants to produce their own food by the process of photosynthesis
Tiny holes in the leaves of the plant where gases like carbon dioxide and oxygen enter and exit
A type of sugar that is produced by the plant during photosynthesis; this is the material that makes the plant grow and is also its food
An organism that makes its own food by converting inorganic molecules to complex organic molecules
A membrane system found within chloroplasts that contains the pigments for photosynthesis.
The solution that surrounds the thylakoids in a chloroplast.
A stack of thylakoids within a cholorplast.
Granum (grana for plural)
Reaction in thylakoids in which light and water are used to produce oxygen, ATP, and reduced NADP
Light dependent reaction
Uses products from the light dependent reaction to convert carbon dioxide to an organic molecule (usually sugar)
Light independent reaction
These cells change shape to open or close the stoma
They use energy from light to transform carbon dioxide and water into sugar (glucose) and oxygen.
In C3 and CAM plants, _________ cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis.
Their membranes contain molecular "machinery" used to convert light energy to chemical energy.
What are the two stages of photosynthesis?
light dependent and light independent
The second of two major stages in photosynthesis (following the light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate.
Temporarily stores energized electrons produced during the light reactions.
The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis.
The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).
An accessory pigment, either yellow or orange, in the chloroplasts of plants and in some prokaryotes. By absorbing wavelengths of light that chlorophyll cannot, carotenoids broaden the spectrum of colors that can drive photosynthesis.
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
They absorb light best at different wavelengths.
A complex of proteins associated with a special pair of chlorophyll a molecules and a primary electron acceptor.
Located centrally in a photosystem, this complex triggers the light reactions of photosynthesis.
Excited by light energy, the pair of chlorophylls donates an electron to the primary electron acceptor, which passes an electron to an electron transport chain.
One of two light-capturing units in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P680 chlorophyll a at its reaction center.
A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has two molecules of P700 chlorophyll a at its reaction center.
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.
Light harvesting complex
In the thylakoid membrane of a chloroplast or in the membrane of some prokaryotes, a specialized molecule that shares the reaction-center complex with a pair of chlorophyll a molecules and that accepts an electron from them.
Primary electron acceptor
A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis.
Glyceraldehyde 3-phosphate (G3P)
What are the 3 phases of Calvin cycle?
Energy Consumption and Redox
Release of G3P; Regeneration of RuBP
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output.
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.
In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
What is the flow of electrons during photosynthesis?
H2O → NADPH → Calvin cycle
No release of oxygen during this phase.
The light reactions of photosynthesis supply the Calvin cycle with ______ & _______.
ATP and NADPH
How is photosynthesis similar in C4 plants and CAM plants?
Rubisco is not used to fix carbon initially.
Three molecules of carbon dioxide are added to three molecules of a five-carbon sugar abbreviated RuBP. These molecules are then rearranged to form six molecules called 3-PGA, which have three carbons each.
Carbon fixation in the calvin cycle
Photoelectric effect is used to ..
Convert the light energy to bond energy
What is the equation for carbon fixation?
CO2 ----> glucose
Overall photosynthesis is ____.
What are accessory pigments?
Pigments other than CHLOROPHYLL A
Lipid-type molecules that absorb visible light; examples Chlorophyll a chlorophyll b, carotene etc
Where is the chlorophyll located?
Thylakoid membrane of chloroplast
It shows the range and efficiency of photons it is capable of absorbing.
Captures light energy in the absence of chloroplasts
Site of photosynthesis is in ______ layer.
How are chloroplasts organized?
1. Intermembrane space
2. Stroma (calvin cycle)
3. Thylakoid space (inside a thylakoid disk)
one stack of thylakoid membranes
What does the inner thylakoid membrane contain?
Photosystem II and I
Captures light energy by exciting chlorophyll molecules.
Photosystems II and I
Light reaction (light dependent RXN)
Fixes carbon (converts CO2 to G3P)
Calvin cycle (light independent RXN)
What does a photosystem consist of (3 things)?
1. Antenna complex (accessory pigments)
2. Reaction center (chlorophyll a)
-Reaction center P680
-ETC makes ATP
-Final electron acceptor is reaction center of PS I
-Reaction center P700
-ETC makes NADPH
-Final electron acceptor is NADP+
Transfers light energy through the accessory pigments.
Photons of light excite electrons on pigments, creating an electrical current known as the _________.
In which photosystem does photoelectric effect occur?
PS II antenna complex
Where does photolysis occur?
What is photolysis?
Water is split releasing oxygen and hydrogen ions in PS II
How does ETC of PS II make ATP?
Photophosphorylation and ATP synthase
What does ETC of PS I make?
Where does light independent reaction occur?
Cyclical pathway in photosynthesis
What is the key enzyme in Calvin cycle?
What does the Calvin cycle regenerate?
What does light independent reaction oxidize and recycle?
Recycles NADP+ and ADP
What is RuBP?
5C substrate in Calvin cycle that binds to carbon dioxide
1. Carbon fixation
2. Reduction to produce G3P (3C sugar)
3. Requires RuBP to bind to CO2
RUBISCO enzyme catalyzes C-fixation
What do cells need to build carbs?
1. energy (ATP from light dependent)
2. reduction potential (NADPH from PS I)
3. carbon dioxide from environment
RuBP + CO2 ----> 2 molecules PGA
PGA reduced to G3P
Reduction to sugar
1 G3P devoted to glucose synthesis
5 G3P used to regenerate RuBP
Regeneration of RuBP
The carbon fixation reaction is catalyzed by the enzyme ______.
____ turns needed to make 1 glucose and 5 RuBP.
Total of 1 G3P generated per ___ turns of Calvin.
__ G3P are recycled to make RuBP
What happens to the one G3P that is not recycled to make RuBP?
Leaves chloroplast to be used to make 6C sugar.
What enters the Calvin cycle?
What leaves the Calvin cycle?
G3P, ADP, NADP+
For every 6 CO2 entering Calvin, it requires:
- ___ ATP
- ___ NADPH
to generate ___ G3P
In warmer temps, rubisco enzyme more likely binds oxygen instead of carbon dioxide. What is the name of this process?
When does stomata close?
At night, on hot dry days
What happens when stomata closes?
No access to carbon dioxide and oxygen builds up
In photorespiration O2 competes with CO2 for the active site in the enzyme rubisco.
_____ adds O2 to the Calvin cycle instead of CO2
Which plant can avoid photorespiration?
Why can C4 plants avoid photorespiration?
They can use an enzyme other than rubisco for the initial C-fixation
What other enzyme could be used for the initial carbon fixation?
PEP carboxylase to fix CO2 to become a 4C molecule called oxaloacetate
The C4 uses 2 cells separating carbon fixation from light reactions. What are they?
Mesophyll cell (c-fixation)
Bundle Sheath cell (Calvin)
What happens in the C4 mesophyll cell?
PEP carboxylase captures CO2
Makes a 4-carbon product which is moved into a bundle sheath cell
What happens in the bundle sheath cell?
1. The 4C is cleaved to 3C sending the CO2 to the Calvin cycle
2. The 3C returns to Mesophyll cell
What do CAM plants do?
Open stomata at night and close during the day