Nursing Elites

1. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

2. What controls the involuntary, rhythmic contractions of the heart muscle?

• A. Lungs
• B. Brain
• C. Spinal cord
• D. Sinoatrial node (located within the heart)

Correct answer: D

Rationale: The correct answer is D: Sinoatrial node (located within the heart). The involuntary, rhythmic contractions of the heart muscle are controlled by a specialized group of cells located within the heart called the sinoatrial node (SA node). The SA node acts as the heart's natural pacemaker, producing electrical impulses that regulate the heart rate and synchronize the contractions of the heart muscle. Choices A, B, and C (Lungs, Brain, Spinal cord) are not responsible for directly influencing the rhythmic contractions of the heart muscle.

3. Which muscle type is characterized by a combination of voluntary and involuntary control, is striated, and is responsible for pumping blood throughout the circulatory system?

• A. Skeletal muscle
• B. Smooth muscle
• C. Cardiac muscle
• D. Connective tissue

Correct answer: C

Rationale: The correct answer is C, Cardiac muscle. Cardiac muscle is characterized by a combination of voluntary and involuntary control, is striated, and is responsible for pumping blood throughout the circulatory system. Skeletal muscle is primarily under voluntary control, smooth muscle is primarily under involuntary control, and connective tissue is not a muscle type, but rather provides support and structure to the body.

4. Which of the following is considered an intensive property?

• A. Mass
• B. Weight
• C. Volume
• D. Density

Correct answer: D

Rationale: Density is an intensive property because it does not depend on the amount of matter present. Intensive properties are independent of the quantity of the substance and remain constant regardless of the size or amount of the sample being measured. Mass, weight, and volume are extensive properties that depend on the amount of substance present. Mass and weight change with the amount of matter, while volume changes as the quantity of the substance changes. Therefore, they are not considered intensive properties.

5. What functional group is present in ethers?

• A. Hydroxyl
• B. Carbonyl
• C. Ether
• D. Amine

Correct answer: C

Rationale: The functional group present in ethers is -O-, representing an oxygen atom bonded to two alkyl or aryl groups. Therefore, choice C, 'Ether,' is the correct answer. Choices A, B, and D refer to different functional groups: hydroxyl (-OH), carbonyl (C=O), and amine (NH2), respectively, which are not present in ethers. Ethers are characterized by the oxygen atom bonded to two carbon groups, distinguishing them from the other functional groups mentioned in the choices.

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