AP Biology : AP Biology
Study concepts, example questions & explanations for AP Biology
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Example Questions
Example Question #2211 : Ap Biology
How do enzymes increase reaction rates?
Increasing pH
Increasing temperature
Increasing activation energy
Decreasing activation energy
Decreasing activation energy
Enzymes increase the rate of reactions through stabilizing the transition state, which decreases activation energy.
Example Question #2212 : Ap Biology
Which of the following does not affect enzyme activity?
substrate concentration
All of the above
temperature
pH
All of the above
pH and temperature affect enzyme activity, as there is an optimal pH and temperature for each enzyme, and a pH or temperature too far from the optimal level can cause the enzyme to denature. Substrate concentration affects enzyme activity; increasing substrate concentration will increase the rate of reaction to the point that the enzymes are saturated.
Example Question #1 : Photosynthesis
Where does the Calvin Cycle take place?
Thylakoid membrane
Mitochondrial lumen
Chloroplast outer membrane
Stroma
Cytoplasm
Stroma
The Calvin Cycle (dark reactions) take place in the stroma of the chloroplasts, which is the aqueous space inside the organelle.
Example Question #2 : Photosynthesis
Where does the Calvin cycle take place in the chloroplasts?
Nucleus
Stroma
Mitochondria
Thylakoid
Stroma
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.
Example Question #3 : Photosynthesis
What is the name of the light-independent reaction of photosynthesis?
Beta-oxidation
Krebs cycle
Calvin cycle
Glycolysis
Calvin cycle
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.
Example Question #4 : Photosynthesis
Which is not a step of the light independent reaction?
carbon fixation
production of G3P
light absorption in photosystem II
regeneration of RuBP
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.
Example Question #1 : Photosynthesis
Where do light independent reactions of photosynthesis occur?
thylakoid of chloroplasts
ribosome
nucleus
stroma of chloroplasts
stroma of chloroplasts
Light independent reactions occur in the stroma of the chloroplasts. Light dependent reactions occur in the thylakoid membrane.
Example Question #1 : Understand Light Independent Reactions (Calvin Cycle)
What the products of the light independent reactions?
CO2, NADPH, ATP
O2, NADP+, ATP
glucose, NADP+, H2O
glucose, NADPH, H2O
glucose, NADP+, H2O
Light independent reactions occur in the stroma of the chloroplasts. Light dependent reactions occur in the thylakoid membrane.
Example Question #1 : Understand Light Independent Reactions (Calvin Cycle)
What the products of the light independent reactions?
O2, NADP+, ATP
glucose, NADP+, H2O
glucose, NADPH, H2O
CO2, NADPH, ATP
glucose, NADP+, H2O
The products of the light independent reaction are glucose, NADP+, and H2O. The reactants are CO2, NADPH, and ATP.
Example Question #1 : Understand Light Independent Reactions (Calvin Cycle)
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
ribulose bisphosphate carboxylase; carbon fixation during the first step of light independent 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.
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