Nursing Elites

1. What is the structure that attaches to each chromosome during mitosis?

• A. Centromere
• B. Telomere
• C. Spindle apparatus
• D. Nucleolus

Correct answer: A

Rationale: The correct answer is the centromere. It is the structure that attaches to each chromosome during mitosis. The centromere serves as the attachment point for spindle fibers during cell division, ensuring proper distribution of chromosomes to daughter cells. Telomeres are found at the ends of chromosomes, providing protection and stability. The spindle apparatus is responsible for separating chromosomes during cell division. The nucleolus, located within the nucleus, is involved in ribosomal RNA synthesis and not in chromosome attachment during mitosis.

2. Which hormone is responsible for milk production in the breasts after childbirth?

• A. Estrogen
• B. Prolactin
• C. Oxytocin
• D. Relaxin

Correct answer: B

Rationale: Prolactin is the hormone responsible for milk production in the breasts after childbirth. It is produced by the pituitary gland and stimulates the mammary glands to produce milk. Estrogen aids in the development of breast tissue during pregnancy but is not directly involved in milk production. Oxytocin is responsible for milk ejection during breastfeeding, while Relaxin helps relax uterine muscles during pregnancy but is not directly linked to milk production.

3. Which of the following hormones is primarily responsible for regulating metabolism?

• A. Insulin
• B. Testosterone
• C. Adrenaline
• D. Thyroid hormone

Correct answer: D

Rationale: Thyroid hormone is the correct answer as it is primarily responsible for regulating metabolism. It plays a crucial role in controlling the body's metabolic rate, affecting how the body uses energy from food. Thyroid hormone levels can influence metabolism, energy production, and body weight regulation. Insulin, choice A, is involved in regulating blood sugar levels, not directly metabolism. Testosterone, choice B, is a sex hormone that primarily affects the development of male reproductive tissues. Adrenaline, choice C, is involved in the fight-or-flight response and not primarily responsible for regulating metabolism.

4. What is the process of transporting molecules across the cell membrane against a concentration gradient called?

• A. Diffusion
• B. Osmosis
• C. Active transport
• D. Facilitated diffusion

Correct answer: C

Rationale: A) Diffusion is the movement of molecules from an area of higher concentration to an area of lower concentration, which does not require energy input. B) Osmosis is the movement of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. C) Active transport is the process of transporting molecules across the cell membrane against a concentration gradient, requiring energy in the form of ATP to move substances from an area of lower concentration to an area of higher concentration. D) Facilitated diffusion is a type of passive transport that involves the use of transport proteins to move molecules across the cell membrane from an area of higher concentration to an area of lower concentration, without the need for energy input.

5. During embryonic development, most vertebrates exhibit structures called pharyngeal pouches. These pouches eventually develop into different structures in various vertebrate groups, such as the human jaw and inner ear. Pharyngeal pouches are an example of:

• A. Analogous structures with different evolutionary origins but similar functions
• B. Homologous structures with a common evolutionary origin but diverse functions
• C. Vestigial structures that no longer serve a vital function in some organisms
• D. Atavisms, the reappearance of a trait absent in recent generations

Correct answer: B

Rationale: Pharyngeal pouches in vertebrates are an example of homologous structures because they share a common evolutionary origin. Despite developing into different structures in various vertebrate groups, such as the jaw and inner ear in humans, these structures originated from the same ancestral feature. This concept of homology highlights the evolutionary relationship between different species and how structures can be modified over time to serve different functions while retaining a common origin. Choice A is incorrect because analogous structures have similar functions but different evolutionary origins, which does not apply to pharyngeal pouches. Choice C is incorrect as vestigial structures are remnants of features that were functional in ancestors but have reduced or lost their original function, which is not the case for pharyngeal pouches. Choice D is incorrect because atavisms refer to the reappearance of traits absent in recent generations, which is not the characteristic of pharyngeal pouches.

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