Quiz
Photosynthesis: light reactions and the Calvin cycle
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Perguntas do quiz (40)
1What two molecules produced during the light-capturing reactions of photosynthesis are used in the Calvin cycle?
- Acarbon dioxide and oxygen
- Boxygen and water
- Cglucose and oxygen
- DNADPH and ATP
2Just like in cellular respiration, the first stage of photosynthesis occurs outside the chloroplasts in the cytosol.
- AVerdadeiro
- BFalso
3The molecules that absorb only certain wavelengths of light energy from the sun to begin the photosynthetic reactions are called _____.
- Apigments
- Bstroma
- Cchloroplasts
- Doxygen
4Chlorophyll molecules donate electrons to an electron acceptor ____
- Aat night
- Bin the antenna complex
- Cin the reaction center
- Dwhen fluorescence occurs
5What molecule is released when water is split in the light reactions of photosynthesis?
- Acarbon dioxide
- BNADPH
- Cchlorophyll
- Doxygen
6In the Z-scheme ____ is the initial electron donor and ____ is the final electron acceptor.
- Awater; oxygen
- BATP; carbon dioxide
- CNADPH; oxygen
- Dwater; NADP+
7Which statement is most accurate concerning how photosystem II compares to the electron transport chain (ETC) of mitochondria?
- AThe ETC associated with photosystem II shares no similar components with the ETC of mitochondria.
- BPhotosystem II produces ATP through chemiosmosis; the ETC of mitochondria produces ATP through substrate-level phosphorylation.
- CIn both systems, ATP is produced by chemiosmosis.
- DIn both systems, high-energy electrons come from NADH
8During the Calvin cycle, carbon dioxide is _____ to drive the formation of sugars.
- Aproduced
- Brecycled
- Coxidized
- Dreduced
9Plant leaves contain openings called _____, which allow the diffusion of carbon dioxide into the leaf tissue.
- ACAM
- Bmesophyll
- Cstomata
- Dcalvins
10The enzyme that catalyzes the fixation of carbon dioxide in photosynthesis is _____.
- AATP synthase
- Bcarbon dioxidase
- Crubisco
- Dchlorophyll
11Why is it not entirely accurate to adopt the common phrase "light-independent reactions" when referring to the Calvin cycle?
- AThe Calvin cycle occurs only when stomata are open, which is triggered by light.
- BAlthough its reactions are not triggered directly by light, they depend on the products of light-capturing reactions.
- CBiologists have discovered that its reactions are triggered directly by light.
- DCalvin cycle enzymes are found in the same cellular location as photosystems I and II.
12Which statement best explains why the overall process of photosynthesis (carbon dioxide + water ( carbohydrate + oxygen gas) requires an input of energy?
- AThere are more molecules on the reactant side than the product side.
- BThe products have lower potential energy than the reactants.
- CThe products have higher potential energy than the reactants
- DThe products and the reactants have equal potential energy.
13Suppose that a pigment had a discrete energy state that corresponded to the energy in green light. Where would you draw this energy state on the diagram shown below?
- AAt a lower energy level than energy state one
- BAt an energy level between energy states one and two
- CAt the same energy level as energy state two
- DAt a higher energy level than energy state two
14Why is measuring the rate of oxygen production in chloroplasts appropriate for estimating the rate of photosynthesis?
- AThe Calvin cycle produces oxygen.
- BOxygen is produced by "splitting" water in the photosystem I complex.
- COxygen is produced by splitting CO2 in the photosystem II complex.
- DOxygen is produced by "splitting" water in the photosystem II complex.
15What is the role of plastocyanin in the Z-scheme model?
- AIt carries protons across the thylakoid membrane to produce a proton gradient used in ATP synthesis.
- BIt captures the photon energy that excites electrons.
- CIt shuttles electrons between the cytochrome complex and photosystem I.
- DIt transfers electrons directly from photosystem II to photosystem I.
16Which statement is correct regarding how CO2 is delivered to rubisco in C3, C4, or CAM plants?
- AIn C3 plants, CO2 is delivered via three-carbon organic acids.
- BIn C4 plants, CO2 is delivered via four-carbon organic acids.
- CIn C3 plants, CO2 is first stockpiled in cells where rubisco is inactive.
- DIn CAM plants, CO2 is first stockpiled in cells where rubisco is inactive.
17At what part of the day would there be the highest concentration of 4-C acids in CAM plants?
- AThere is a constant concentration throughout the day.
- BMidday
- CMorning
- DNight
18In antenna complexes, how is energy transferred among the pigment molecules?
- Aby fluorescence
- Bby resonance
- Cby heat
- Dby redox reactions
19Why is chlorophyll green?
- AIt absorbs all wavelengths in the visible spectrum.
- BIt absorbs wavelengths in only the blue and red parts of the visible spectrum.
- CIt absorbs wavelengths only in the blue part of the visible spectrum.
- DIt absorbs wavelengths only in the red portions of the spectrum (680 nm, 700 nm).
20At what point in photosynthesis is the electromagnetic energy of light first converted into chemical energy?
- AThe conversion first occurs when electrons are transferred from excited pigments to an electron carrier in a photosystem.
- BThe conversion first occurs when the proton-motive force drives the production of ATP.
- CThe conversion first occurs when the photosystem II complex enzymes remove electrons from water, leaving protons and oxygen.
- DThe conversion first occurs when protons are transferred from the stroma to the lumen side of the thylakoid membrane.
21Because cell walls consist of a cross-linked network of long filaments embedded in a stiff surrounding material, they can be called _____.
- Aspongy bone
- Bplasma membranes
- Cfiber composites
- Dspot-welded sheets
22The most abundant protein found in the extracellular matrix of animal cells is _____.
- APectin
- BHemoglobin
- CCellulose
- DCollagen
23The type of cell–cell attachment that resembles quilting, with proteins acting as stitches, is _____.
- Atight junctions
- Bdesmosomes
- Cgap junctions
- Dselective adhesions
24What role do plasmodesmata play in plant cells?
- AThey prevent the plant cell from losing water in desert conditions.
- BThey allow the plant cell to withstand extreme temperatures.
- CThey serve as sites of protein production in the cell.
- DThey serve as communication portals between neighboring plant cells, allowing the passage of small molecules between the two cells.
25Why does a hormone act only on specific cell types in an organism and not others?
- AAll cells will bind to the hormone and process it, but not all cells will produce a response.
- BA cell must have the appropriate receptor before it can bind to the hormone.
- CHormones are prevented from entering the bloodstream, and thus only act on the releasing cell itself.
- DHormones only act on cells that are adjacent to the releasing cell.
26The long and complex series of events that occurs when a signal binds to the cell surface and is converted from one form to another is called _____.
- Aaction potential
- Btransesterification reaction
- Csignal cross-wiring
- Dsignal transduction
27How can a hormone that is present in very small quantities within the bloodstream elicit such a large response within a cell?
- AThe signal is always an extra-large macromolecule even though it is present in minute quantities.
- BCells degrade the hormone into many tiny molecules, and then each piece creates a response within the cell.
- CThe signal is only bound by the largest cells in the body, and thus they can elicit a large response.
- DThe message from the hormone is amplified many times within the cell.
28How is phosphorylation important in a signal transduction cascade?
- AWhen the hormone itself becomes phosphorylated, it travels to all nearby cells and activates them to release more hormones of that same type.
- BA hormone will phosphorylate the entire cell, thus causing the cell to be marked for destruction.
- CPhosphorylation will change the activity of target proteins, which triggers another response in the cell.
- DPhosphorylation always shuts down a signal transduction cascade, thus leading to an end of the signal.
29Why is it important for signal transduction systems to trigger a rapid response within a cell and be able to be shut down quickly?
- ACells are unable to respond quickly to hormones, and therefore signal transduction cascades always occur over a long time.
- BAll signal transduction cascades are shut down immediately so as to prevent the cell from mounting a response.
- CCells often have to respond very quickly to changes in their internal and external environments.
- DCells must be able to function alone, because they are unable to work together in a coordinated fashion.
30A bacterium lacking the receptor for responding to quorum-sensing signals would be unable to ________.
- Amount a coordinated response with other microbes
- Bdivide
- Cprocess food from the environment and perform glycolysis
- Dsynthesize a cell wall
31Which statement is most accurate concerning how the molecular composition of a plant cell wall compares with the ECM of animal cells?
- APlant cell wall fibers consist primarily of carbohydrates; ECM fibers are dominated by proteins
- BPlant cell walls exhibit fundamentally different structural principles than ECM
- CIn the plant cell wall, the ground substance surrounding the fibers contains carbohydrates; in the ECM, it does not.
- DThe fibers in a plant cell wall are primarily proteins; ECM fibers are dominated by carbohydrates.
32Which statement best describes what would happen if you treated cells in a developing frog embryo with a molecule that blocked a cadherin present in muscle tissue?
- AConnections between the cytoskeleton of muscle cells and the ECM would be disrupted.
- BAdhesion of muscle cells to other muscle cells would be disrupted.
- CAdhesion of muscle cells to cells of non-muscle tissues would be disrupted.
- DThe formation of the middle lamella between adjacent muscle cells would be disrupted.
33Which of the following statements most accurately describes the function of plasmodesmata in plant cells or gap junctions in animal cells?
- APlasmodesmata allow passage of proteins and small molecules between adjacent cells.
- BGap junctions allow passage of proteins and small molecules between adjacent cells.
- CGap junctions allow passage of only proteins between adjacent cells.
- DPlasmodesmata allow passage of only proteins between adjacent cells.
34Which statement most accurately explains how some signals are amplified?
- AEnzymes remove phosphate groups from proteins.
- BMore hormone is produced.
- CSecond messengers are produced.
- DReceptors are blocked.
35Based on what you have learned about how cells ensure that proteins end up in the right place (Chapter 7), what type of signal would you expect to be exposed on a cytosolic receptor after a steroid hormone changes the receptor's conformation?
- AA specific sugar that targets proteins to lysosomes.
- BAmino acids that facilitate diffusion through the nuclear envelope
- CAn ER (endoplasmic reticulum) signal sequence.
- DAmino acids required for transport through the nuclear pore complex
36How do only certain cells respond to particular signaling molecules that may be sent throughout the body?
- AThey express the appropriate receptor.
- BThey express the Ras protein.
- CThey express the appropriate G protein.
- DThey express the appropriate second messenger(s).
37Where are protein components of the extracellular matrix synthesized?
- Ain the extracellular layer itself
- Bin the plasma membrane
- Cin the Golgi apparatus
- Din the rough ER
38What characteristics do desmosomes bestow on tissues that use these adhesions to connect adjacent cells?
- AThey use the extracellular matrix to indirectly connect adjacent cells.
- BThey provide strong connections to resist pulling forces.
- CThey form a watertight barrier between the cells.
- DThey allow communication between adjacent cells.
39Summarize the experimental evidence in sponges showing that animal cells adhere to each other selectively. Explain the molecular basis of selective adhesion.
- ASelective adhesion results from the presence of specific cell flagella. The flagella search for cells with the same type of flagella and if find, then they attach to each other.
- BSelective adhesion results from the presence of specific types of cell adhesion proteins in the plasma membrane, including cadherins. Each type of protein can bind only to proteins of the same type.
- CSelective adhesion results from the presence of specific types of cell adhesion lipids in the plasma membrane, including phospholipids. Each type of protein can bind only to lipids of the same type.
- DSelective adhesion results from the presence of specific types of cell adhesion carbohydrates in the plasma membrane. Each type of protein can bind only to carbohydrates of the same type.
40What does it mean to say that a signal is transduced?
- AThe signal is amplified.
- BThe physical form of the signal changes between the outside of the cell and the inside.
- CThe signal is generated by the production of proteins.
- DThe signaling molecule enters the cell directly and elicits a cellular response.
Informações
- Descrição
- Biology Quiz sobre Sem título, criado por Tracy Louque em 26-07-2017.
- Autor
- Tracy Louque
- Idioma
- English
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