Nursing Elites

1. What type of molecule forms the cell membrane and controls what enters and exits the cell?

• A. Proteins
• B. Carbohydrates
• C. Lipids
• D. Nucleic acids

Correct answer: C

Rationale: The correct answer is C: Lipids. The cell membrane is primarily composed of a double layer of lipids called phospholipids. These phospholipids have a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, which arrange themselves to form a barrier that controls the passage of substances in and out of the cell. While proteins are also present in the cell membrane and play important roles in transport and cell signaling, lipids are the main structural component responsible for the selective permeability of the membrane. Carbohydrates are typically found on the outer surface of the membrane and are involved in cell recognition and communication. Nucleic acids are not a major component of the cell membrane; they are primarily responsible for storing and transmitting genetic information within the cell.

2. Percent Increase/Decrease: A medication dosage is increased by 20%. If the original dosage was 100mg, what is the new dosage?

• A. 80mg
• B. 100mg
• C. 120mg
• D. 140mg

Correct answer: C

Rationale: Multiply the original dosage (100mg) by 1 + the percentage increase (20% = 0.2) to get 120mg.

3. What happens to the density of a gas when its temperature increases at constant pressure?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Information insufficient

Correct answer: B

Rationale: As gas particles gain thermal energy with increasing temperature, they spread out, decreasing the density.

4. How does the structure of centromeres contribute to chromosome movement during mitosis?

• A. The centromere provides a binding site for spindle fibers, allowing chromosomes to be attached and manipulated.
• B. The centromere serves as a dividing point between sister chromatids, ensuring their separation during anaphase.
• C. The centromere maintains chromosome stability by preventing chromosomal breaks and rearrangements.
• D. The centromere plays a role in DNA replication, ensuring accurate copying of the genetic material.

Correct answer: A

Rationale: Rationale: A) The centromere provides a binding site for spindle fibers, which are microtubules that help move chromosomes during cell division. This attachment allows the chromosomes to be pulled towards opposite poles of the cell during mitosis. Therefore, the structure of centromeres directly contributes to chromosome movement during mitosis by facilitating the attachment and manipulation of chromosomes by the spindle fibers. B) While the centromere does serve as a dividing point between sister chromatids, ensuring their separation during anaphase, this function is more related to the segregation of chromosomes rather than their movement. C) The centromere does play a role in maintaining chromosome stability by ensuring proper chromosome segregation, but it is not primarily responsible for preventing chromosomal breaks and rearrangements. D) The centromere is not directly involved in DNA replication. Its main function is

5. Which of the following statements is true regarding a supersaturated solution?

• A. It is unstable and tends to crystallize
• B. It contains less solute than it could dissolve
• C. It has a lower concentration than a saturated solution
• D. It is rarely encountered in everyday solutions

Correct answer: a

Rationale: Supersaturated solutions are unstable and tend to crystallize if disturbed. The other choices do not accurately describe supersaturated solutions.

6. A scientist observes a new species of bird with uniquely shaped wings. They hypothesize that the wing shape allows for superior gliding ability. Which observation would most strongly support this hypothesis?

• A. The bird is found in mountainous regions.
• B. The bird has feathers with low friction.
• C. The bird can fly long distances without flapping.
• D. The bird's wing muscles are stronger than other birds.

Correct answer: C

Rationale: Direct observation of gliding ability directly tests the hypothesis about the wing shape's function. Other observations might be relevant but provide less direct evidence.

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