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. Which structure in the body is responsible for detecting light and converting it into signals for the brain?

• A. Iris
• B. Retina
• C. Lens
• D. Pupil

Correct answer: B

Rationale: The correct answer is the Retina. The retina in the eye contains specialized cells called photoreceptors that detect light and convert it into neural signals. These signals are then transmitted to the brain via the optic nerve for visual processing. The iris is responsible for controlling the amount of light entering the eye by adjusting the size of the pupil, while the lens helps focus light onto the retina. The pupil is simply the opening in the center of the iris that allows light to enter the eye.

3. What is the primary function of coronary arteries?

• A. Delivering oxygenated blood throughout the body.
• B. Supplying oxygenated blood to the heart muscle itself.
• C. Carrying deoxygenated blood back to the heart.
• D. Regulating blood pressure through vasoconstriction and vasodilation.

Correct answer: B

Rationale: The primary function of coronary arteries is to supply oxygenated blood to the heart muscle itself. The heart is a muscle that needs a constant supply of oxygen and nutrients to function properly. Coronary arteries branch off the aorta and specifically deliver oxygenated blood to the heart muscle, ensuring its proper function. Choice A is incorrect because coronary arteries do not deliver blood throughout the entire body but specifically to the heart. Choice C is incorrect as coronary arteries carry oxygenated blood away from the heart. Choice D is incorrect as the primary function of the coronary arteries is not to regulate blood pressure but rather to provide oxygenated blood to the heart muscle.

4. Which of these body parts does not contain melanin?

• A. Hair
• B. Nails
• C. Skin
• D. Iris

Correct answer: D

Rationale: The iris is the colored part of the eye that determines the eye's color. Melanin is not present in the iris, unlike hair, nails, and skin. Melanin gives color to hair, nails, and skin, but not to the iris. Therefore, the correct answer is the iris (Choice D). Choices A, B, and C contain melanin and are incorrect.

5. Which of the following compounds often contains a carboxyl group?

• A. Carbohydrates
• B. Glycolipids
• C. Amino Acids
• D. DNA

Correct answer: C

Rationale: The correct answer is C: Amino Acids. Amino acids, the building blocks of proteins, contain both an amine group and a carboxyl group. The carboxyl group (-COOH) is crucial for the structure and function of proteins as it participates in peptide bond formation. Carbohydrates and DNA do not typically contain carboxyl groups as a functional group. Glycolipids consist of a carbohydrate chain linked to a lipid, but they do not inherently contain a carboxyl group.

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