Nursing Elites

1. How does the stability of an atom's nucleus influence its radioactive decay?

• A. Stable nuclei never undergo radioactive decay.
• B. Unstable nuclei are more likely to decay through various processes.
• C. Decay releases energy, making stable nuclei more prone to it.
• D. The element's position on the periodic table determines its decay rate.

Correct answer: B

Rationale: Unstable nuclei are more likely to decay through various processes. The stability of an atom's nucleus is a key factor in determining whether it will undergo radioactive decay. Unstable nuclei have an excess of either protons or neutrons, leading to an imbalance in the nucleus. To achieve a more stable configuration, these nuclei will undergo radioactive decay by emitting particles or energy. Stable nuclei, on the other hand, are less likely to undergo radioactive decay as they have a balanced number of protons and neutrons.

2. How are genetic markers used in paternity testing?

• A. They identify unique sequences in the father's DNA present in the child.
• B. They analyze the presence or absence of specific alleles for certain genes.
• C. They compare the child's blood type to the parents' blood types.
• D. They measure the child's physical resemblance to the father.

Correct answer: B

Rationale: Rationale: Genetic markers are specific DNA sequences that can vary among individuals. In paternity testing, genetic markers are used to compare the DNA of the child with that of the alleged father. By analyzing the presence or absence of specific alleles (different forms of a gene) at these genetic markers, scientists can determine the likelihood of paternity. This method is more accurate and reliable than comparing blood types or physical resemblance, making option B the most appropriate choice.

3. What is a mutation?

• A. A change in the DNA sequence
• B. A type of protein
• C. A normal part of the DNA replication process
• D. A harmless variation in DNA

Correct answer: A

Rationale: Rationale: A mutation is defined as a change in the DNA sequence. Mutations can occur due to various factors such as errors during DNA replication, exposure to mutagens (e.g., chemicals, radiation), or spontaneous changes. These changes can result in alterations to the genetic information carried by an organism, which can have different effects ranging from harmless variations to causing genetic disorders or diseases. Mutations are a fundamental aspect of genetic diversity and evolution. Options B, C, and D do not accurately describe what a mutation is.

4. The tiny contractile units within muscle cells are called:

• A. Myocytes
• B. Myofibrils
• C. Sarcomeres
• D. Tendons

Correct answer: C

Rationale: The correct answer is C: Sarcomeres. Sarcomeres are the basic contractile units within muscle cells. They are made up of overlapping filaments of actin and myosin proteins, which slide past each other during muscle contraction, resulting in muscle movement. Myocytes (A) are muscle cells, myofibrils (B) are cylindrical structures within muscle fibers composed of sarcomeres, and tendons (D) are tough bands of connective tissue that connect muscle to bone. Therefore, sarcomeres are specifically responsible for muscle contraction within muscle cells.

5. Neurons, the functional units of the nervous system, belong to which tissue type?

• A. Epithelial tissue
• B. Connective tissue
• C. Muscle tissue
• D. Nervous tissue

Correct answer: D

Rationale: The correct answer is D: Nervous tissue. Neurons are specialized cells that transmit nerve impulses and are the primary components of the nervous system. Nervous tissue is made up of neurons and supporting cells called neuroglia. Neurons are responsible for processing and transmitting information throughout the body, making them a crucial part of the nervous system. Epithelial tissue (A) is primarily involved in covering and lining surfaces, connective tissue (B) supports and connects other tissues, and muscle tissue (C) is responsible for movement. Therefore, neurons belong to nervous tissue, which is specialized for communication and coordination within the body.

6. The main function of the nephrons is to:

• A. Store urine
• B. Filter blood and remove waste products
• C. Produce hormones
• D. Control blood pressure

Correct answer: B

Rationale: The correct answer is B: 'Filter blood and remove waste products.' Nephrons are the functional units of the kidneys responsible for filtering blood to remove waste products, excess ions, and water, while reabsorbing essential substances like glucose and amino acids. This process forms urine, which is stored in the bladder before being excreted. Options A, C, and D are incorrect because nephrons do not store urine, produce hormones, or directly control blood pressure; although the kidneys do play a role in long-term blood pressure regulation through mechanisms like the renin-angiotensin-aldosterone system.

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