Which best explains the role of plant pigments in photosynthesis?
Produce photon energy
Absorb light energy
Provide electrons
Convert heat to electricity
The Correct Answer is B
Choice A rationale: Plant pigments do not produce photon energy, but rather capture it from the sun. Photon energy is the energy carried by particles of light, called photons. Different types of electromagnetic radiation, such as visible light, have different amounts of photon energy depending on their wavelength¹.
Choice B rationale: Plant pigments absorb light energy and use it to initiate photosynthesis. Photosynthesis is the process by which plants convert light energy into chemical energy, stored in the bonds of sugar molecules. Plant pigments are specialized organic molecules, such as chlorophyll and carotenoids, that are found in the chloroplasts of plant cells. They absorb specific wavelengths of light and reflect others, giving plants their characteristic colors²³.
Choice C rationale: Plant pigments do not provide electrons, but rather transfer them to other molecules. Electrons are negatively charged subatomic particles that are involved in chemical reactions. In photosynthesis, plant pigments absorb light energy and use it to split water molecules, releasing electrons, protons, and oxygen. The electrons are then passed along an electron transport chain, generating a proton gradient that drives the synthesis of ATP, an energy molecule. The electrons are also used to reduce NADP+ to NADPH, an electron carrier⁴.
Choice D rationale: Plant pigments do not convert heat to electricity, but rather convert light to chemical energy. Heat and electricity are both forms of energy, but they are not directly involved in photosynthesis. Heat is the kinetic energy of molecules, while electricity is the flow of electrons or electric charge. Plant pigments absorb light energy and use it to drive the chemical reactions of photosynthesis, which produce sugar and oxygen as products⁵.
Choice E rationale: Plant pigments do not reduce NADP, but rather donate electrons to it. Reduction is a chemical reaction in which a molecule gains electrons, while oxidation is a chemical reaction in which a molecule loses electrons. NADP+ is an oxidized form of NADP, which stands for nicotinamide adenine dinucleotide phosphate. It is an electron carrier that accepts electrons from plant pigments in photosystem I, a complex of proteins and pigments in the thylakoid membrane of the chloroplast. The reduced form of NADP is NADPH, which carries electrons and hydrogen for the dark reaction of photosynthesis, which uses CO2 to produce glucose⁶.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A rationale: A cover slip is correct because a cover slip is a thin, transparent piece of glass or plastic that can be placed over the specimen on the slide. A cover slip protects the specimen from drying out, dust, or damage, and creates a flat surface for viewing under the microscope.
Choice B rationale: Clear paper is incorrect because clear paper is not suitable for covering a wet mount specimen. Clear paper is a type of paper that is transparent or translucent, but it is not thin or flat enough to fit over the specimen on the slide. Clear paper can also interfere with the passage of light or distort the image of the specimen.
Choice C rationale: Transparent tape is incorrect because transparent tape is also not suitable for covering a wet mount specimen. Transparent tape is a type of adhesive tape that is clear or see-through, but it is sticky and can damage the specimen or the slide. Transparent tape can also affect the quality of the image or the focus of the microscope.
Choice D rationale: Another glass slide is incorrect because another glass slide is too thick and heavy to cover a wet mount specimen. Another glass slide is a thin, flat piece of glass or plastic that can be used to place the specimen on, but not over it. Another glass slide can also crush the specimen or block the light source of the microscope.
Correct Answer is D
Explanation
Choice A rationale: CO2 is not the source of oxygen produced by a plant, but a reactant of the dark reaction. The dark reaction uses CO2 and energy intermediates from the light reaction to produce glucose, a type of sugar. The dark reaction does not release any oxygen¹.
Choice B rationale: C6H12O6 is the chemical formula for glucose, which is the product of the dark reaction. Glucose is synthesized from CO2 and energy intermediates from the light reaction. Glucose does not produce any oxygen, but can be used by the plant for respiration or storage².
Choice C rationale: Glyceraldehyde-3-phosphate is an intermediate molecule in the dark reaction. It is formed from CO2 and energy intermediates from the light reaction, and then converted into glucose. Glyceraldehyde-3-phosphate does not produce any oxygen³.
Choice D rationale: H2O is the source of oxygen produced by a plant. In the light reaction, water is split by the energy from sunlight in photosystem II, releasing electrons, protons, and oxygen. The oxygen is either used for respiration or released into the air⁴.
Choice E rationale: O2 is the product of oxygen produced by a plant, not the source. O2 is released as a by-product of the splitting of water in photosystem II. O2 is either used for respiration or released into the air⁴.
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