AP Biology › Understand light independent reactions (Calvin cycle)
Where does the Calvin Cycle take place?
Stroma
Thylakoid membrane
Mitochondrial lumen
Cytoplasm
Chloroplast outer membrane
The Calvin Cycle (dark reactions) take place in the stroma of the chloroplasts, which is the aqueous space inside the organelle.
Which is not a step of the light independent reaction?
carbon fixation
regeneration of RuBP
production of G3P
light absorption in photosystem II
Absorption of sunlight in photosystem II is the first step of the light dependent reaction, not the light independent reaction. During the light independent reaction, or the Calvin Cycle, carbon fixation first occurs. CO2 produced during the light dependent reaction reacts with RuBP, ultimately producing PGA. This reaction is catalyzed by the enzyme Rubisco. Then, PGA is converted to G3P, using ATP and NADPH produced during the light dependent reaction. The G3P is ultimately converted to glucose. Every 3 cycles of the Calvin Cycle (light independent reaction), 6 molecules of G3P are produced; only 1 is used to produce glucose. The remaining 5 molecules of G3P are used to regenerate RuBP to allow the Calvin Cycle to continue.
Where does the Calvin cycle take place in the chloroplasts?
Stroma
Thylakoid
Mitochondria
Nucleus
The Calvin cycle takes place in the stroma area in the chloroplasts. The mitochondria is another organelle, and the nucleus contains the DNA. The thylakoids are in the chloroplasts and contain the pigment chlorophyll in which the light reactions occur.
What the products of the light independent reactions?
CO2, NADPH, ATP
glucose, NADPH, H2O
glucose, NADP+, H2O
O2, NADP+, ATP
The products of the light independent reaction are glucose, NADP+, and H2O. The reactants are CO2, NADPH, and ATP.
What is the name of the light-independent reaction of photosynthesis?
Calvin cycle
Krebs cycle
Glycolysis
Beta-oxidation
The light-independent reaction in photosynthesis is called the Calvin cycle. Glycolysis and the Krebs cycle are the first and second steps in cellular respiration, respectively. Beta-oxidation is the process by which fatty acids are broken down into acetyl-CoA, which may enter the Krebs cycle, ultimately to produce ATP.
What the products of the light independent reactions?
CO2, NADPH, ATP
glucose, NADPH, H2O
glucose, NADP+, H2O
O2, NADP+, ATP
Light independent reactions occur in the stroma of the chloroplasts. Light dependent reactions occur in the thylakoid membrane.
Which enzyme is important in photosynthesis, and what is its function?
ribulose bisphosphate carboxylase; carbon fixation during the first step of light independent reaction
amylase; carbon fixation during the first step of light independent reaction
ribulose bisphosphate carboxylase; captures energy from the sun during light dependent reaction
oxidase; captures energy from the sun during light dependent reaction
During the first step of the light independent reaction, or Calvin Cycle, CO2 produced from the light dependent reaction reacts with RuBP. This reaction is catalyzed by Rubisco, or ribulose bisphosphate carboxylase.
Which is not a required input for the Calvin Cycle?
CO2
ATP
NADPH
sunlight
The Calvin Cycle, or light independent reaction, does not utilize sunlight as an input. During the light independent reaction, or the Calvin Cycle, carbon fixation first occurs. CO2 produced during the light dependent reaction reacts with RuBP, ultimately producing PGA. This reaction is catalyzed by the enzyme Rubisco. Then, PGA is converted to G3P, using ATP and NADPH produced during the light dependent reaction to allow this reaction to occur. The G3P is ultimately converted to glucose. Every 3 cycles of the Calvin Cycle (light independent reaction), 6 molecules of G3P are produced; only 1 is used to produce glucose. The remaining 5 molecules of G3P are used to regenerate RuBP to allow the Calvin Cycle to continue.
How many G3P molecules are produced after 3 cycles of the Calvin Cycle; and how many of these G3P molecules are used to produce glucose after 3 cycles of the Calvin Cycle?
1; 1
3; 1
6; 1
6; 3
Every 3 cycles of the Calvin Cycle (light independent reaction), 6 molecules of G3P are produced; only 1 is used to produce glucose. The remaining 5 molecules of G3P are used to regenerate RuBP to allow the Calvin Cycle to continue.
Where do light independent reactions of photosynthesis occur?
stroma of chloroplasts
thylakoid of chloroplasts
ribosome
nucleus
Light independent reactions occur in the stroma of the chloroplasts. Light dependent reactions occur in the thylakoid membrane.