Mastering Biology Chapter 10
In addition to sugars, Jamal could add "O2" to the model as a form of energy that links photosynthesis and cell respiration.
False
This model shows that the mass of apples is derived from sunlight.
False
True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain.
False
True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.
False
Plant leaves contain openings called stomata, which allow the diffusion of _______.
H2O, CO2, and O2
1. In the light reactions, light energy is used to oxidize _____to ____.
H2O, O2
Talia and Franco have worked together on a model of photosynthesis, but their model reveals a common misconception. What correction(s) can you offer to fix the model?
O2 should not be shown to be derived from CO2. O2 should be shown to be derived from H2O. O2 should not be a product of the Calvin cycle. O2 should be shown as a product of the light-capturing reactions.
Which term describes ATP production resulting from the capture of light energy by chlorophyll?
Photophosphorylation
An investigator exposes chloroplasts to 700-nm photons and observes low O2 production, but high ATP production. Which of the following best explains this observation?
Photosystem II is not splitting water, and the ATP is being produced by cycling electrons via photosystem I.
According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?
Proton Gradient
Which of the following particles can pass through the ATP synthase channel?
Protons
Carbon fixation involves the addition of carbon dioxide to _____.
RuBP
Which molecule is regenerated in the regeneration phase of the Calvin cycle? Without regeneration of this molecule, the Calvin cycle would stop.
RuBP
How are the light-capturing reactions and the Calvin cycle interdependent on each other?
The Calvin cycle requires the ATP and NADPH produced in the light-capturing reactions, while the inputs to the light-capturing reactions are regenerated by the Calvin cycle.
True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.
true
The light reactions of photosynthesis use _____ and produce _____.
water ... NADPH
Both PS II and PS I
- Light absorption - the reduction of primary electron acceptor.
Photosystem I only
- Reduction of NADP+ - Oxidation of electron transport chain between two photosystems
Chlorophyll can be found in _____.
A and C The photosystems contain chlorophyll.
_____ splits water into 1/2 O2, H+, and e- .
A, photosystem II
Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5 . The solution is then adjusted to pH 8 . Which of the following conclusions can be drawn from these experimental conditions?
ATP will not be produced because there is no ADP and inorganic phosphate in the solution.
The noncyclic electron flow of photosystem II and I splits water to donate electrons and produce a proton gradient (motive force). The electrons are accepted by NAD+ to make NADPH. The proton gradient is used to make ______ through the _______.
ATP; ATP synthase
When electrons in photopigments become excited, what is the result of the energy input?
All the above are possible outcomes.
At what part of the day would there be the highest concentration of four-carbon organic acids in the vacuoles of CAM plants?
At sunrise, since these acids are made during the night and used up during the day
Which process produces oxygen?
photosynthesis
The molecules that absorb only certain wavelengths of light energy from the sun to begin the photosynthetic reactions are called _____.
pigments
_____ has a longer wavelength than _____.
red and green
During the Calvin cycle, carbon dioxide is _____ to drive the formation of sugars.
reduced
The enzyme that catalyzes the fixation of carbon dioxide in photosynthesis is _____.
rubisco
During photosynthesis, the light energy from the sun is captured and stored in the bonds of _____.
sugars
What assumptions did Engelmann make in order to conclude that red and violet-blue light were more effective than green light in driving photosynthesis? Select the two that apply.
- The number of bacteria clustered at each wavelength (color) was approximately proportional to the amount of oxygen being produced by that portion of the alga. - The distribution of chloroplasts within each algal cell was approximately the same.
Photosystem II only
- oxidations of water - reduction of electron transport chain between the two photosystems
In the Calvin cycle, how many ATP molecules are required to regenerate RuBP from five G3P molecules?
3
Assuming 1 ATP is produced for each pair of electrons used to form NADPH, calculate the number of photons used to produce a new G3P and regenerate RuBP.
36 photons
How many carbon dioxide molecules must be added to RuBP to make a single molecule of glucose?
6
Which of these equations best summarizes photosynthesis?
6 CO2 + 6 H2O → C6H12O6 + 6 O2
Identify the chloroplast.
A
_____ releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment.
B
How is energy transferred among antenna pigment molecules?
By resonance
Energized electrons from ____ are used to reduce NADP+.
C
Peter has drawn a model to track the path of carbons during photosynthesis. He used red balls to indicate carbons and ignored oxygens and hydrogens.
CO2 / Calvin cycle
4. The electrons derived from this oxidation reaction in the Calvin cycle are used to reduce _____ to ______.
CO2, G3P
Identify a thylakoid.
D
Identify the stroma.
E
Where does the Calvin cycle occur?
E
Which of these phosphorylates ADP to make ATP?
E; ATP synthase
Why is chlorophyll green?
It absorbs wavelengths in only the blue and red parts of the visible spectrum.
What is the role of PEP carboxylase in C4 and CAM plants?
It fixes CO2 into an organic acid.
Which of the following correctly identify a role of the ATP produced in the light-capturing reactions?
It is used to regenerate RuBP from G3P molecules.
Which of the following correctly describes the flow of energy through photosystem II and the ETC?
Light → Antenna pigments → Reaction center → Pheophytin → ETC → Proton gradient → ATP synthase.
2. The electrons derived from this oxidation reaction in the light reactions are used to reduce _____ to ______.
NADP+, NADPH
After 3-PGA is phosphorylated, it is reduced by _____.
NADPH
Which of the following molecules is the primary product of photosystem I?
NADPH
3. The Calvin cycle oxidizes the light-reactions product _____ to _____.
NADPH, NADP+
Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis?
The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions.
What is the importance of the light-independent reactions in terms of carbon flow in the biosphere?
The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars.
What molecule is split in the oxygen-releasing light reactions of photosynthesis?
Water
Suppose that the concentration of CO2 available for the Calvin cycle decreased by 50% (because the stomata closed to conserve water). Which statement correctly describes how O2 production would be affected? (Assume that the light intensity does not change.)
The rate of O2 production would decrease because the rate of ADP and NADP+ production by the Calvin cycle would decrease.
Why are violet-to-blue and red photons the most effective at driving photosynthesis?
These are the wavelengths of light absorbed by chlorophyll molecules.
NADPH and ATP are two molecules produced during the light-capturing reactions of photosynthesis. What are these molecules used for later in photosynthesis in the Calvin cycle?
They are used to convert carbon dioxide into sugar in the Calvin cycle.
What is the biological significance of the light-independent reactions of photosynthesis?
They convert carbon dioxide to sugar.
It would be appropriate for Jamal to label sugars and ATP as forms of chemical energy.
True
This model is correct, but Jamal could also have divided the first step into two to show the light-capturing reactions first, then the Calvin cycle
True
Lin has drawn a model to track the pathway of energy from sunlight to the sugars in an apple tree.
light-capturing reactions / Calvin cycle
Which set of reactions uses H2O and produces O2?
light dependent reactions
