Nursing Elites

1. Myelin sheath is a fatty substance that insulates and protects the long extensions of some nerve cells. It is produced by:

• A. Schwann cells
• B. Astrocytes
• C. Neurons
• D. Oligodendrocytes

Correct answer: A

Rationale: The correct answer is A: Schwann cells. Schwann cells are a type of glial cell in the peripheral nervous system that produce the myelin sheath around axons. Myelin sheath is essential for the rapid conduction of nerve impulses and provides insulation and protection to nerve fibers. Astrocytes are glial cells that provide support and maintain homeostasis in the central nervous system, but they do not produce myelin. Neurons are the main functional units of the nervous system responsible for transmitting nerve impulses. Oligodendrocytes are another type of glial cell in the central nervous system that produce myelin sheath around axons in that region, not in the peripheral nervous system where Schwann cells are responsible for myelination.

2. According to Newton's third law of motion, if you push against a wall with a certain force, the wall will push back with:

• A. A smaller force
• B. An equal force
• C. A greater force
• D. No force at all

Correct answer: b

Rationale: Newton's third law states that for every action, there is an equal and opposite reaction.

3. Which word in the sentence "The quick brown fox jumps over the lazy dog" demonstrates alliteration?

• A. quick
• B. brown
• C. fox
• D. jumps

Correct answer: A

Rationale: Alliteration is the repetition of the first consonant sound of words close together. In this case, "quick" and "brown" both start with the "k" sound.

4. 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.

5. What is the work done by a force of 20 N acting on an object that moves 5 meters in the direction of the force?

• A. 100 Joules (J)
• B. 25 Joules (J)
• C. 4 Joules (J)
• D. Work cannot be determined without knowing the object's mass.

Correct answer: A

Rationale: Work is defined as the force applied multiplied by the distance moved in the direction of the force. Work = force x distance = 20 N x 5 m = 100 J.

6. What enzyme plays a crucial role in DNA replication during the S phase of interphase?

• A. Helicase
• B. DNA polymerase
• C. Ligase
• D. Topoisomerase

Correct answer: B

Rationale: Rationale: During the S phase of interphase, DNA replication occurs. DNA polymerase is the enzyme responsible for synthesizing new DNA strands by adding nucleotides in a complementary fashion to the template strand. It plays a crucial role in replicating the entire genome accurately. Helicase unwinds the double-stranded DNA, topoisomerase relieves the tension in the DNA strands, and ligase joins the Okazaki fragments on the lagging strand. However, DNA polymerase is the enzyme directly involved in the synthesis of new DNA strands during replication.

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