The objective lenses of the compound light microscope are attached to the
Body tube.
Stage.
Base.
Rotating nosepiece.
The Correct Answer is D
Choice A rationale: Body tube is incorrect because the body tube is the part of the microscope that connects the eyepiece to the objective lenses, not the part that holds the objective lenses. The body tube is a hollow cylinder that allows the passage of light from the objective lenses to the eyepiece.
Choice B rationale: Stage is incorrect because the stage is the part of the microscope that supports the slide and the specimen, not the part that holds the objective lenses. The stage is a flat platform that has a hole in the center to allow the light source to illuminate the specimen.
Choice C rationale: Base is incorrect because the base is the part of the microscope that supports the whole microscope, not the part that holds the objective lenses. The base is the bottom part of the microscope that provides stability and balance.
Choice D rationale: Rotating nosepiece is correct because the rotating nosepiece is the part of the microscope that holds the objective lenses and allows them to be changed. The rotating nosepiece is a circular structure that has four or more objective lenses attached to it. The rotating nosepiece can be rotated to switch between different magnifications of the objective lenses.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Diffusion is a passive process that does not require energy input from the cell. It is driven by the random motion of molecules that results in a net movement from regions of higher concentration to regions of lower concentration.
Diffusion is one of the ways that substances can cross the cell membrane, such as oxygen, carbon dioxide, and water. Diffusion is important for cellular functions, such as gas exchange, nutrient uptake, and waste removal. Diffusion also helps maintain the homeostasis of the cell by balancing the concentration gradients of different molecules. Therefore, diffusion is the movement of a molecule from an area of higher concentration to an area of lower concentration.
Correct Answer is A
Explanation
Choice A rationale: Iodine is a chemical element that forms a brown solution of iodine and potassium iodide, known as iodine solution. When this solution is added to a sample that contains starch, it forms a complex with the starch molecules, which changes the color of the solution to blue-black. This is based on the fact that starch is a polysaccharide that has a helical structure, which can trap the iodine molecules inside. ²
Choice B rationale: Biuret is a chemical compound that forms a blue solution of copper (II) sulfate and sodium hydroxide, known as biuret reagent. When this reagent is added to a sample that contains proteins or peptides, it forms a complex with the copper (II) ions, which changes the color of the solution to violet or pink. This is based on the fact that proteins and peptides have peptide bonds, which have nitrogen atoms that can coordinate with the copper (II) ions. ³
Choice C rationale: Benedict's is a chemical compound that forms a blue solution of copper (II) sulfate, sodium carbonate, and sodium citrate, known as Benedict's reagent. When this reagent is heated with a sample that contains reducing sugars, such as glucose or maltose, it reduces the copper (II) ions to copper (I) ions, which form a red, orange, or green precipitate of copper (I) oxide. This is based on the fact that reducing sugars have free aldehyde or ketone groups that can donate electrons to the copper (II) ions. ⁴
Choice D rationale: Phenol red is a chemical compound that forms a red solution that is used as a pH indicator. When this solution is added to a sample that has an acidic or neutral pH, it remains red or turns yellow. When this solution is added to a sample that has an alkaline pH, it turns pink or fuchsia. This is based on the fact that phenol red has a sulfonated hydroxyquinone group that can lose or gain protons depending on the pH of the solution. ⁵
Choice E rationale: Sudan IV is a chemical compound that forms a red powder that is used as a stain for lipids. When this powder is dissolved in a solvent and added to a sample that contains lipids, such as fats or oils, it dissolves in the lipids and stains them red. When this solution is added to a sample that does not contain lipids, it remains in the solvent and does not stain the sample. This is based on the fact that Sudan IV is a nonpolar compound that can dissolve in nonpolar substances like lipids, but not in polar substances like water. ⁶.
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