Nursing Elites

1. What is the role of enzymes in the body?

• A. To transport oxygen
• B. To speed up chemical reactions
• C. To regulate body temperature
• D. To store energy

Correct answer: B

Rationale: Enzymes act as biological catalysts that speed up chemical reactions in the body. They lower the activation energy required for reactions to occur, thus facilitating processes like digestion, metabolism, and other essential functions. Choice A is incorrect as the transportation of oxygen is primarily carried out by red blood cells. Choice C is incorrect as the regulation of body temperature involves mechanisms such as sweating and shivering. Choice D is incorrect as energy storage is mainly performed by molecules like glycogen and triglycerides.

2. Chromatids divide into identical chromosomes and migrate to opposite ends of the cell in which of the following phases of mitosis?

• A. metaphase
• B. anaphase
• C. prophase
• D. telophase

Correct answer: B

Rationale: During anaphase of mitosis, the sister chromatids detach from each other and migrate to opposite poles of the cell. This process ensures that each daughter cell ultimately receives an identical set of chromosomes, as the chromatids separate and become individual chromosomes again. This is a crucial step in ensuring accurate distribution of genetic material during cell division. In metaphase, the chromosomes align at the cell's equator but do not separate yet. Prophase is the phase where chromatin condenses into chromosomes and the nuclear envelope breaks down. Telophase is the final phase where the nuclear envelope reforms around the separated chromosomes.

3. Which of the following enzymes unwinds the double-stranded DNA during replication?

• A. Helicase
• B. Ligase
• C. Nuclease
• D. Polymerase

Correct answer: A

Rationale: Helicase is the enzyme responsible for unwinding the double-stranded DNA during replication by breaking the hydrogen bonds between the base pairs. This process creates the replication fork where DNA polymerase can then synthesize new DNA strands. Ligase functions to join Okazaki fragments on the lagging strand, not unwind DNA. Nuclease is involved in DNA repair by removing damaged DNA segments. Polymerase is responsible for synthesizing new DNA strands based on the existing template strands, not for unwinding the DNA.

4. What are chromosomes made of?

• A. DNA and RNA
• B. DNA and protein
• C. Protein and RNA
• D. DNA and lipids

Correct answer: B

Rationale: Chromosomes are made up of DNA and associated proteins. These proteins help package and organize the DNA within the cell, playing a crucial role in gene regulation and cell division. While RNA is involved in various cellular processes, it is not a primary component of chromosomes. Lipids are not a fundamental component of chromosomes, which primarily consist of DNA and proteins.

5. 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.

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