Nursing Elites

1. Which part of the plant produces pollen?

• A. Anther
• B. Style
• C. Stigma
• D. Pistil

Correct answer: A

Rationale: The anther is the part of the flower that produces pollen. It is located at the tip of the stamen, the male reproductive organ of a flower. The anther contains pollen sacs where pollen grains are produced. The style is the part of the pistil that connects the stigma to the ovary, playing a role in pollen tube growth. The stigma is the part of the pistil that receives pollen during fertilization. The pistil is the female reproductive organ of a flower, consisting of the stigma, style, and ovary, and does not produce pollen.

2. Cells that line the inner or outer surfaces of organs or body cavities are often linked together by intimate physical connections. These connections are referred to as ______.

• A. Separate desmosomes
• B. Ronofilaments
• C. Tight junctions
• D. Fascia adherens

Correct answer: C

Rationale: The correct answer is C: Tight junctions. Tight junctions, also known as zonula occludens, are the intimate physical connections between cells that line the inner or outer surfaces of organs or body cavities. These junctions form a virtually impermeable barrier to fluid, creating a tight seal between the cells. This helps in maintaining the integrity and function of the tissue as well as regulating the movement of substances across the cell layer. Choice A, Separate desmosomes, are cell structures that provide strong adhesion between cells but do not create a barrier to fluid. Choice B, Ronofilaments, is not a term used to describe the connections between cells. Choice D, Fascia adherens, are another type of cell junction involved in cell adhesion, but they are different from tight junctions in terms of their structure and function.

3. Which of the following is an example of human error in an experiment?

• A. an imperfectly calibrated scale
• B. contaminating a sterile sample by breathing on it
• C. a draft in the laboratory slightly changing the temperature of a liquid
• D. failure to account for wind speed when measuring distance traveled

Correct answer: B

Rationale: Contaminating a sterile sample by breathing on it is an example of human error in an experiment because it involves an action directly caused by the researcher that compromises the integrity of the sample. Breathing on a sterile sample introduces external contaminants that can affect the results. Choices A, C, and D involve factors not directly under the researcher's control or are technical errors that do not involve direct human actions.

4. Huntington’s disease is carried on the dominant allele. In a situation where two heterozygous parents have the disease, what percentage of their offspring are predicted to be disease-free?

• A. 0%
• B. 25%
• C. 50%
• D. 100%

Correct answer: B

Rationale: In this scenario, both parents are heterozygous for Huntington's disease, meaning each carries one dominant allele (representing the disease) and one recessive allele (representing no disease). When they have offspring, there is a 25% chance that each child will inherit two recessive alleles, making them disease-free. The Punnett square for two heterozygous parents (Hh x Hh) yields a 25% probability of offspring being homozygous recessive (hh) and therefore disease-free. Choice A (0%) is incorrect because there is a possibility of disease-free offspring. Choice C (50%) is incorrect as it represents the likelihood of being a carrier. Choice D (100%) is incorrect as all offspring will not be disease-free in this scenario.

5. Which of the following is always true about molecules?

• A. They cannot travel through all cell membranes
• B. They move from low concentration to high concentration without using energy
• C. They move from high concentration to low concentration without using energy
• D. They cannot move

Correct answer: C

Rationale: The statement that molecules move from high concentration to low concentration without using energy is always true due to the natural process of diffusion. This movement occurs to reach equilibrium and does not require any additional energy input directly from the molecule itself. Choice A is incorrect because not all molecules can travel through all cell membranes. Choice B is incorrect as molecules typically move from high concentration to low concentration in a process known as passive transport. Choice D is incorrect as molecules are in constant motion due to factors like temperature and kinetic energy.

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