Nursing Elites

1. Which of the following nucleic acids carries the genetic information copied from DNA to the ribosomes?

• A. DNA
• B. mRNA
• C. rRNA
• D. tRNA

Correct answer: B

Rationale: The correct answer is B: mRNA. Messenger RNA (mRNA) is responsible for carrying the genetic information copied from DNA to the ribosomes for protein synthesis. mRNA serves as a temporary copy of the genetic instructions stored in DNA and acts as a messenger between the nucleus and ribosomes in the cytoplasm where protein synthesis occurs. While rRNA (ribosomal RNA) and tRNA (transfer RNA) play essential roles in the process of translation at the ribosomes, mRNA is the nucleic acid directly involved in carrying the genetic code for protein synthesis. Therefore, choices A, C, and D are incorrect as DNA is the original genetic material, rRNA is a component of the ribosomes, and tRNA carries amino acids during protein synthesis, respectively.

2. Which of the following sets of valves is primarily responsible for preventing blood flow from major blood vessels to the heart?

• A. atrioventricular valves
• B. semilunar valves
• C. tricuspid valves
• D. bicuspid valves

Correct answer: B

Rationale: The correct answer is B: semilunar valves. Semilunar valves are primarily responsible for preventing blood flow from major blood vessels to the heart. These valves are located at the base of the aorta and the pulmonary artery, ensuring blood flows in one direction only by closing when the ventricles relax to prevent blood from flowing back into the heart. Choices A, C, and D are incorrect. Atrioventricular valves (choice A) include the tricuspid and bicuspid valves, which prevent backflow between the atria and ventricles, not major blood vessels. Tricuspid valves (choice C) and bicuspid valves (choice D) are specific types of atrioventricular valves located between the atria and ventricles, not at the base of major blood vessels.

3. Which type of bond involves the complete transfer of electrons between atoms?

• A. Covalent bond
• B. Ionic bond
• C. Metallic bond
• D. Hydrogen bond

Correct answer: B

Rationale: The correct answer is B, Ionic bond. Ionic bond involves the complete transfer of electrons from one atom to another, resulting in the formation of cations and anions. This transfer leads to the creation of strong electrostatic attraction between the oppositely charged ions. Covalent bonds, on the other hand, involve the sharing of electrons between atoms to achieve stability. Metallic bonds are formed in metals, where a sea of delocalized electrons surrounds positively charged metal ions, contributing to the metal's properties. Hydrogen bonds are intermolecular forces that occur between a hydrogen atom and a highly electronegative atom like oxygen or nitrogen, not involving the complete transfer of electrons.

4. Which part of the brain is responsible for regulating heart rate, breathing, and swallowing?

• A. Cerebrum
• B. Cerebellum
• C. Medulla oblongata
• D. Thalamus

Correct answer: C

Rationale: The correct answer is C, the medulla oblongata. This part of the brain, located at the base of the brainstem, is primarily responsible for regulating essential functions like heart rate, breathing, and swallowing. Choices A, B, and D are incorrect. The cerebrum is associated with higher brain functions such as thinking and voluntary movements, the cerebellum controls coordination and balance, and the thalamus serves as a relay station for sensory information. Therefore, the medulla oblongata specifically governs the autonomic functions critical for survival.

5. What is a primary function of red blood cells?

• A. To fight infection
• B. To carry oxygen
• C. To produce antibodies
• D. To transport waste

Correct answer: B

Rationale: The main function of red blood cells is to carry oxygen from the lungs to all the body's tissues and organs, where it is needed for cellular functions and metabolism. This process is essential for sustaining life and providing energy to cells. Choice A is incorrect because fighting infection is primarily done by white blood cells. Choice C is incorrect because antibody production is mainly carried out by specialized white blood cells. Choice D is incorrect as the primary role of red blood cells is not to transport waste, but rather to transport oxygen and some carbon dioxide.

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