Nursing Elites

1. Genes control heredity in man and other organisms. This gene is ___

• A. A segment of DNA
• B. A bead-like structure on the chromosomes
• C. A protein molecule
• D. A segment of RNA

Correct answer: A

Rationale: Genes are sections of DNA that contain instructions for building and operating living organisms. These sections of DNA contain the genetic information that is passed on from one generation to the next. Genes are composed of specific sequences of nucleotides within the DNA molecule. Therefore, genes are best described as segments of DNA. Choice A is correct. Choice B is incorrect because genes are not bead-like structures on chromosomes but specific sequences of DNA. Choice C is incorrect because genes are not protein molecules but rather sequences of nucleotides. Choice D is incorrect because genes are not segments of RNA but DNA.

2. If bacteria are placed in a strong solution of salt water, they will shrink as water moves out of the bacteria. What is this process called?

• A. Dehydration synthesis
• B. Hydrolysis
• C. Osmosis
• D. Isotonic transport

Correct answer: C

Rationale: Osmosis is the process by which water molecules move across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In this case, when bacteria are placed in a strong solution of salt water, the high concentration of solutes outside the bacteria causes water to move out of the bacteria, leading to shrinkage. This process is known as osmosis. Dehydration synthesis (Choice A) is a process where molecules combine by removing water. Hydrolysis (Choice B) is the breakdown of molecules by the addition of water. Isotonic transport (Choice D) does not accurately describe the specific movement of water in or out of bacterial cells in a hypertonic solution.

3. In which phase of mitosis do new nuclear membranes form around sets of chromosomes?

• A. Prophase
• B. Anaphase
• C. Telophase
• D. Interphase

Correct answer: C

Rationale: The correct answer is C, Telophase. During telophase, the final phase of mitosis, new nuclear membranes form around sets of chromosomes at the opposite poles of the cell. This process marks the completion of nuclear division in mitosis. Choices A, B, and D are incorrect because in prophase, chromosomes condense but nuclear membranes are not formed; in anaphase, chromosomes separate and move to opposite poles but no new nuclear membranes are formed; and in interphase, the cell prepares for division but nuclear membranes are not forming around sets of chromosomes.

4. In order, from lower to upper, the layers of the atmosphere are:

• A. Exosphere, thermosphere, mesosphere, stratosphere, troposphere
• B. Troposphere, stratosphere, mesosphere, thermosphere, exosphere
• C. Mesosphere, troposphere, stratosphere, thermosphere, exosphere
• D. Thermosphere, troposphere, stratosphere, mesosphere, exosphere

Correct answer: B

Rationale: The correct order of the layers of the atmosphere, from lower to upper, is troposphere, stratosphere, mesosphere, thermosphere, exosphere. The troposphere is the lowest layer where weather phenomena occur. The stratosphere contains the ozone layer, which absorbs and scatters the solar ultraviolet radiation. The mesosphere is where most meteorites burn up upon entering the Earth's atmosphere. The thermosphere is characterized by high temperatures due to the absorption of solar radiation. The exosphere is the outermost layer where the atmosphere transitions into space. Therefore, option B is the correct sequence, as it reflects the ascending order of the Earth's atmospheric layers.

5. What process involves the movement of water molecules through a selectively permeable membrane?

• A. Diffusion
• B. Osmosis
• C. Active Transport
• D. Facilitated Diffusion

Correct answer: B

Rationale: Osmosis is the process specifically involving the movement of water molecules through a selectively permeable membrane, from an area of higher water concentration to an area of lower water concentration. This process helps balance concentrations on both sides of the membrane. Choice A, Diffusion, refers to the movement of particles from an area of higher concentration to an area of lower concentration, not specific to water. Choice C, Active Transport, requires energy to move substances against their concentration gradient, unlike osmosis. Choice D, Facilitated Diffusion, involves the use of transport proteins to move specific substances across membranes, not limited to water molecules.

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