When testing tonicity in Elodea cells, once Elodea cells were placed in distilled water, what did you observe? Select all that apply.
Cell membranes pressed tightly against the cell walls.
Many of the cells had burst.
Full central vacuoles.
Many of the cells had become crenated.
Correct Answer : A,C
Choice A rationale: Cell membranes pressed tightly against the cell walls is correct because this is what happens when a plant cell is placed in a hypotonic solution. A hypotonic solution has a higher concentration of water than the cell, so water moves into the cell and out of the solution by osmosis, causing the cell to swell and press against the cell wall. This is called turgor and it helps the cell maintain its shape and rigidity.
Choice B rationale: Many of the cells had burst is incorrect because plant cells do not burst in a hypotonic solution, unlike animal cells. Plant cells have a rigid cell wall that prevents them from bursting, even when they are full of water. The cell wall can withstand the pressure of water entering the cell.
Choice C rationale: Full central vacuoles is correct because this is also what happens when a plant cell is placed in a hypotonic solution. The central vacuole is a large organelle that stores water and other substances in the plant cell. When water enters the cell, the central vacuole expands and fills up the cell, increasing its turgor pressure.
Choice D rationale: Many of the cells had become crenated is incorrect because crenation is the opposite of what happens in a hypotonic solution. Crenation is the process by which a cell shrinks and becomes wrinkled due to water loss in a hypertonic solution. A hypertonic solution has a lower concentration of water than the cell, so water moves out of the cell and into the solution by osmosis, causing the cell to shrink.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A rationale: H2O is a reactant or input for the light reaction of photosynthesis. In the light reaction, water is split by the energy from sunlight in photosystem II, releasing electrons, protons, and oxygen. The electrons and protons are used to reduce NADP+ to NADPH and to synthesize ATP from ADP and Pi. The oxygen is either used for respiration or released into the air¹².
Choice B rationale: Oxygen is not a reactant or input for the light reaction of photosynthesis, but a product or output. Oxygen is released as a by-product of the splitting of water in photosystem II. Oxygen is either used for respiration or released into the air¹².
Choice C rationale: NADPH is not a reactant or input for the light reaction of photosynthesis, but a product or output. NADPH is an electron carrier that is reduced by the electrons from water in photosystem I. NADPH provides electrons and hydrogen for the dark reaction, which uses CO2 to produce glucose¹².
Choice D rationale: ATP is not a reactant or input for the light reaction of photosynthesis, but a product or output. ATP is an energy molecule that is synthesized by the enzyme ATP synthase using the proton gradient created by the electron transport chain. ATP provides energy for the dark reaction, which uses CO2 to produce glucose¹².
Choice E rationale: Carbon dioxide is not a reactant or input for the light reaction of photosynthesis, but a reactant or input for 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 require light and can occur in the day or night¹².
Correct Answer is B
Explanation
Choice A rationale: High power is incorrect because high power is the second highest magnification objective lens, not the highest. High power is also called the 40x objective lens because it magnifies the specimen by 40 times. When combined with the 10x eyepiece lens, the total magnification is 400x.
Choice B rationale: Oil immersion is correct because oil immersion is the highest magnification objective lens. Oil immersion is also called the 100x objective lens because it magnifies the specimen by 100 times. When combined with the 10x eyepiece lens, the total magnification is 1000x. Oil immersion requires oil to be applied between the slide and the lens to reduce the refraction of light and increase the clarity of the image.
Choice C rationale: Low power is incorrect because low power is the second lowest magnification objective lens, not the highest. Low power is also called the 10x objective lens because it magnifies the specimen by 10 times. When combined with the 10x eyepiece lens, the total magnification is 100x.
Choice D rationale: Scanning is incorrect because scanning is the lowest magnification objective lens, not the highest. Scanning is also called the 4x objective lens because it magnifies the specimen by 4 times. When combined with the 10x eyepiece lens, the total magnification is 40x. Scanning is used to scan the whole slide and find the specimen.
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