Exam 2 Flashcards
Which of the following proteins or protein complexes is involv on the transfer of protons (H+) as electrons flow through the electron transport chain of photosystem II? A. Plastocyanin B. Plastoquinone C. Pheophytin D. Cytochrome b/f E. Ferredoxin
D. Cytochrome b/f
Plants that fix CO2 into organic acids inside one cell type, and then transport the acids into another cell type where they are decarboxylated and Calvin cycle occurs, are called?
C4 plants
The primary function of the Calvin cycle of photosynthesis is:
To produce energy-rich carbohydrate from carbon dioxide and water
Which of following catalyzes the set of biochemical reactions collectively known as photolysis? A. Cytochrome b/f B. primary electron acceptor C. Oxygen evolving complex D. NADP reductase complex E. ATP synthase
C. Oxygen evolving complex
What is the main role of the antennae pigment molecules of photosystems?
A. Synthesize ATP from ADP and Pi
B. to pass electrons to NADPH
C. To split water and release oxygen to the reaction center chlorophyll
D. To concentrate photons inside the stroma
E. none of the above
E. none of the above
Describe the role of the protomotive force (pmf) in photosynthesis.
pmf is required for the production of ATP by ATP synthase
In C4 photosynthesis, carbon fixation takes place in the ______ cells, and then transferred as maleate or aspartate to the ______ cells, where carbon dioxide is released for entry into the Calvin cycle.
Mesophyll, bundle-sheath
A genetic mutation adversely affects the activity of ferrodoxin in such a way that it does not function properly. What is the expected affect on photosynthesis?
NADPH will not be produced and cyclical electron transport will not occur
All of the following compounds are required reactants (I.e., are necessary for chemical reactions to proceed) at some stage of photosynthesis EXCEPT: A. ATP B. NADPH C. Oxygen D. Carbon dioxide E. water
Oxygen
As the light reactions proceeds which part of the chloroplast is expected to how the higher pH? (I.e., to be most basic)
Stroma
Linear electron transport can be distinguished from cyclic electron transport in that:
A. Linear generates NADPH only and cyclic generates ATP only (via pmf)
B. linear generates ATP only and cyclic generates NADPH only
C. Linear and cyclic generate both NADPH and ATP
D. Cyclic generates ATP and NADPH and linear generates NADPH only
E. none of the above
A. Linear generates NADPH only and cyclic generates ATP only (via pmf)
To produce a net gain of one PGAL molecule, the Calvin cycle must turnover ______ time(s). This requires ______.
Three; 9 ATP and 6 NADPH
The mode of action for a particular herbicide is to block the flow of electrons from ferrodoxin to cytochrome b/f during electron transport of the light reactions of photosynthesis. What affect is this herbicide expected to have on the light reactions?
It will compromise the production of ATP
Describe the relationship between photosynthesis and cellular respiration.
Photosynthesis stores energy in complex organic molecules and respiration converts to ATP
In plant cells, ATP is made in response to light. An electron transport chain is involved. This electron transport chain is found:
On the thylakoid membranes of chloroplasts
Which of the following statements regarding phytochrome is FALSE?
A. The Pr form of phytochrome is converted to the Pfr form upon exposure to red light
B. the Pfr form of phytochrome is converted to the Pr form upon exposure to far-red light
C. The Pfr form of phytochrome may either stimulate or inhibit flowering
D. The Pfr form of phytochrome is rapidly converted to the Pr during the dark period
E. phytochrome does not control flowering in some species
D.
This hormone is critical to fruit ripening and senscence (I.e., withering of plant structures)
Ethylene
Movement through the plant body occur by diffusion through parenchyma cells
Auxin
Induced phototropism response by stimulating cell growth (elongation)
Auxin
Important hormone in regulating stomatal movement
Abscisic acid (ABA)
Critical hormone in regulating seed germination and seedling growth
Gibberellin
Which of the following does not favor the oxygenate activity of RUBISCO?
A. Elevated temp
B. elevated CO2 concentrations
C. Elevated O2 concentrations
D. Prolonged closing of stomates
E. dry, high-light intensity environments
B. elevated CO2 concentrations
Which photosystem produces NADPH?
Photosystem I of the light reactions
Which photosystem requires CO2?
Neither photosytem of the light reactions
Which photosystem forms a proton gradient?
Photosystem II of the light reactions
Which photosystem is active in light only?
Both photosystems
Which photosystem has liberation of oxygen?
Photosystem II of the light reactions
Which photosystem produces PGAL that is used to make more complex carbohydrates?
Neither photosytem
Which photosystem is involve in cyclical electron transport?
Both photosystems
Which of the following is NOT an expected consequence of CAM photosynthesis?
A. Th pH of mesophyll tissue will decrease throughout the night
B. gas exchange will occur primarily at night
C. Entry of carbon into the Calvin cycle will occur mostly at night
D. Most initial carbon fixation (fixation by PEP carboxylase) will occur. Night
E. all of the above
C.
In green plants, the primary function of the Calvin cycle is to:
Construct simple sugars from carbon dioxide
Where does the Calvin cycle of photosynthesis take plac
Stroma of the chloroplast
What are the products of the light reactions of photosynthesis that utilized in the Calvin cycle?
ATP and NADPH
What occurs when an antennae complex chlorophyll molecule absorbs light energy?
Electrons from atoms in the absorbing part of the molecule briefly move to a higher energy state before returning to the ground state
The color of light most effective in driving photosynthesis
Blue
Assume a thylakoid is somehow punctured so the interior of the thylakoid (I.e., the lumen) is no longer separated from the stroma. This damage will have the most direct effect in which process?
Synthesis of ATP
In a plant cell, where is the to synthase of photosynthesis located?
Thylakoid membrane
What best describes the mechanism by which stomate opening and closing is regulated?
The movement of potassium chloride, and maleate ions out of guard cells changes the osmolarity and results in closing of stomates
Fruit set and ripening is controlled mostly by hormones produced by the:
Seed following fertilization
Which of the following is NOT part of fruit set and ripening?
A. Conversion of simple sugars to organic acids
B. swelling and growth of the ovary
C. Withering and senescence of other floral parts such as petals and stamens
D. Breakdown of cellulose in the cell walls of the ovary tissue
E. Changes in color associated with chlorophyll breakdown and production of accessory pigments
A
Which hormone functions in maintains apical dominance in plants?
Auxin
Which of the following statements regarding the regulation of flowering by phytochrome is TRUE?
A. The length of e dark period is not important in determining the flowering of either short day or long day plants
B. the Pfr form of phytochrome inhibits flowering in long day plants
C. The Pfr form of phytochrome stimulates flowering in long day plants
D. The Pr form of phytochrome stimulates flowering in long day plants
E. The Pr form of phytochrome stimulates flowering in short day plants
B
Which of th following is NOT a mechanism by which the activities of the light reactions and Calvin cycle are coordinated in photosynthesis?
A. The dependency of the Calvin cycle for the products of the light reactions
B. intermediates created in the Calvin cycle stimulate electron transport in the light reactions
C. Increasing Mg2+ concentrations in the stroma as the light reactions proceed
D. Increasing pH in the stroma as the light reactions proceed
E. stimulation of Calvin cycle enzyme activity by NADPH
B
RUBISCO activity is favored by:
Increasing concentration of reduced ferrodoxin and thioredoxin
Which of the plant genomes is fundamentally eukaryotic in organization and gene structure?
Nuclear
Which of the following contribute to the great variation in size of the nuclear genome in higher plants?
A. Variation in the amount of repetitive DNA present in the nuclear genome
B. variation in the number of chromosomes present in the nuclear genome
C. Variation in the size of the chloroplast genome
D. Variation on the number of copies of the chloroplast genome
E. both a and b
E
What is polyploidy?
- an increase in the number of chromosomes, often in multiples of some standard number
- is associated with processes that often result in speciation in plants
- can result from the fusion of unreduced gametes
