Photosynthesis and Calvin cycle
C3 plants
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.
What are the two stages of photosynthesis
light dependent and light independent
Calvin cycle diagram
*memorize diagram in notes 99https://o.quizlet.com/MFX6Z9BaxhwOulpnHyUHag_m.png
What gives the name C3 Pathway for the calvin cycle?
-3PG (each of the 3PGs have 3 carbons)
What is the first stable form of carbon in photosynthesis?
-3PG / PGA -3 phosphoglycerate / 3 phosphoglyceric acid
1 ) Carbon fixation in calvin cycle
-5C RuBP reacts with CO2 to form a 6C unstable intermediate, which splits into 2 3PG molecules (each has 3 carbons) -Reaction between RuBP and CO2 is driven by the enzyme RUBISCO -3PG is the end result/product of carbon fixation
2) Reduction in calvin cycle
-Adding Hydrogens and electrons -Rearranging matter -Trying to make glucose -Requires ATP and NADPH -End result in G3P (has 3 carbons)
3 phases of calvin cycle
-Carbon fixation: carbon changed from inorganic CO2 to organic C6H12O6 -Reduction: uses ATP and NADPH from light reactions; adding electrons and hydrogens; building up larger molecules -Regeneration of RuBP: uses ATP from light reactions
3) Regeneration of RuBP
-From 3C G3P back to the starting and ending compound 5C RuBP -Requires ATP energy from light reactions
G3P
-Glyceraldehyde-3-phosphate -Made in the calvin cycle, but then leaves but stays in the stroma of the chloroplasts to make glucose -The glucose can be used to make other organic molecules
RUBISCO
-Ribulose biphosphate carboxylase/ oxygenase -Enzyme that drives the first step in the cycle -Most abundant protein in the world -It is unusual because it can accept two different substrates (carboxylase or oxygenase; CO2 is preferred though)
RuBP
-Ribulose bisphosphate -The starting and ending compound in calvin cycle -Has 5 carbons in it
Photosynthesis converts light energy to the chemical energy of food
... - https://o.quizlet.com/Ej6MrETWSgEpnB6.OG-7fw_m.jpg
Describe a chlorophyll molecule
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10.3 The Calvin Cycle uses the chemical energy of ATP and NADPH to reduce CO2 to sugar
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Which of the following equations represents photosynthesis? 6CO2 + 6O2 → C6H12O6 + 6H2O 6H2O + 6O2 → C6H12O6 + 6CO2 C6H12O6 + 6O2 → 6CO2 + 6H2O C6H12O6 + 6CO2 → 6O2 + 6H2O 6CO2 + 6H2O → C6H12O6 + 6O2
6CO2 + 6H2O → C6H12O6 + 6O2
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.
Thylakoids
A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy. - https://o.quizlet.com/UARGIJkBe43fBABZYGPu0g_m.jpg
Thylakoids
A flattened, membranous sac inside a chloroplast. Thylakoids often exist in stacks called grana that are interconnected; their membranes contain molecular "machinery" used to convert light energy to chemical energy.
Chlorophyll
A green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes. Chlorophyll a participates directly in the light reactions, which convert solar energy to chemical energy.
Photosystem I
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.
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.
Photorespiration
A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of O2 rather than CO2 by rubisco.
C4 Plants
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.
CAM plants
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.
What two molecules are produced by the light reactions and used to power the Calvin cycle? CO2 and O2 C6H12O6 and O2 C6H12O6 and RuBP ATP and NADPH G3P and H2O
ATP and NADPH
The light reactions of photosynthesis supply the Calvin cycle with
ATP and NADPH.
Carotenoids
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.
What connects the two photosystems in the light reactions? Chlorophyll A thylakoid An electron transport chain A chain of glucose molecules The Calvin cycle
An electron transport chain - https://o.quizlet.com/3ADysWr0Ksmin0q.z3HEEA_m.jpg
PEP carboxylase
An enzyme that adds CO2 to phosphoenolpyruvate (PEP) to form oxaloacetate in mesophyll cells of C4 plants. It acts prior to photosynthesis.
Heterotrophs
An organism that obtains organic food molecules by eating other organisms or substances derived from them.
In which of the following organelles does photosynthesis take place? Chloroplast Mitochondrion Ribosome Central vacuole Nucleus
Chloroplast
Which of the following statements is a correct distinction between autotrophs and heterotrophs? Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic. Only heterotrophs require oxygen. Cellular respiration is unique to heterotrophs. Only heterotrophs have mitochondria. Only heterotrophs require chemical compounds from the environment.
Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.
What are the three phases of The Calvin cycle?
Carbon Fixation Energy Consumption and Redox Release of G3P; Regeneration of RuBP
What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? Sucrose (C12H22O11) RuBP Carbon dioxide (CO2) Glucose (C6H12O6) G3P (C3H6O3)
Carbon dioxide (CO2): Carbon dioxide provides the carbon atoms that are incorporated into sugars in photosynthesis. Carbon dioxide initially combines with RuBP, and RuBP is regenerated to continue the Calvin cycle.
Which of the following sequences correctly represents the flow of electrons during photosynthesis? NADPH → chlorophyll → Calvin cycle H2O → NADPH → Calvin cycle NADPH → O2 → CO2 NADPH → electron transport chain → O2 H2O → photosystem I → photosystem II
H2O → NADPH → Calvin cycle
What provides electrons for the light reactions? CO2 The Calvin cycle H2O Light O2
H2O: Electrons are stripped from water in the light reactions of photosynthesis. Light provides the energy to excite electrons.
How is photosynthesis similar in C4 plants and CAM plants?
In both cases, rubisco is not used to fix carbon initially.
Primary electron acceptor
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.
What transports electrons from the light reactions to the Calvin cycle? NADH NADPH An electron transport chain FADH2 Chlorophyll
NADPH is an electron carrier that picks up electrons in the light reactions and releases them in the Calvin cycle. An electron transport chain conveys electrons from one photosystem to the other within the light reactions.
NADP
Nicotinamide adenine dinucleotide phosphate, an electron acceptor that, as NADPH, temporarily stores energized electrons produced during the light reactions.
Photo system II
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.
Chloroplasts
absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.
Photosynthesis
The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes.
Where does the Calvin Cycle take place?
The Calvin cycle is a complex series of chemical reactions carried out in the stroma.
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.
Stroma
The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.
Carbon Fixation
The initial incorporation of carbon from CO2 into an organic compound by an autotrophic organism (a plant, another photosynthetic organism, or a chemoautotrophic prokaryote).
Photophosphorylation
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.
Calvin cycle
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.
Describe Carbon Fixation in the Calvin Cycle
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.
Reaction
center complex - 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.
ATP and NADPH are both products of the light reactions and are used to power the Calvin cycle.
https://o.quizlet.com/8Mq1rfmuK86n4lnA5q46Hw_m.jpg
Photosynthesis requires carbon dioxide and water for the production of sugar and oxygen.
https://o.quizlet.com/9l1RPffyxEMRozM.9py5Jw_m.jpg
Chloroplasts use energy from light to transform carbon dioxide and water into sugar and oxygen.
https://o.quizlet.com/R-hMl8fXD8v.27FF8cI7fQ_m.jpg
In mechanism, photophosphorylation is most similar to
oxidative phosphorylation in cellular respiration.
Glyceraldehyde 3
phosphate (G3P) - A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis.
Stomata
pores on the leaf where O2 exits and CO2 enters
Autotrophic
produce their organic molecules from CO2 and other raw material from the environment.
Autotrophs
produce their own organic molecules from CO2
Which of the following does not occur during the Calvin cycle? release of oxygen regeneration of the CO2 acceptor oxidation of NADPH consumption of ATP carbon fixation
release of oxygen
Which process is most directly driven by light energy? creation of a pH gradient by pumping protons across the thylakoid membrane removal of electrons from chlorophyll molecules reduction of NADP+ molecules ATP synthesis carbon fixation in the stroma
removal of electrons from chlorophyll molecules
Bundle
sheath cells - In C4 plants, a type of photosynthetic cell arranged into tightly packed sheaths around the veins of a leaf.
Mesophyll
specialized for photosynthesis. In C3 and CAM plants, mesophyll cells are located between the upper and lower epidermis; in C4 plants, they are located between the bundle-sheath cells and the epidermis.
The light reactions take place in the _________ and the Calvin cycle takes place in the _________. stroma; thylakoids thylakoids; stroma inner membrane; outer membrane chloroplasts; mitochondria mitochondria; chloroplasts
thylakoids; stroma
