Nursing Elites

1. What macromolecules are formed from amino acids, and what are their roles?

• A. Lipids; store energy
• B. Carbohydrates; provide energy
• C. Proteins; perform various functions like catalysis, transport, and structural support
• D. Nucleic acids; store genetic information

Correct answer: C

Rationale: The correct answer is C. Proteins are macromolecules formed from amino acids and have diverse roles, such as serving as enzymes, transport molecules, and providing structural support. They are essential for catalysis, cellular communication, immune response, and many other functions in living organisms. Choices A, B, and D are incorrect. Lipids are not formed from amino acids but from fatty acids and glycerol, mainly serving as energy storage molecules. Carbohydrates are composed of sugars and provide energy to the body. Nucleic acids, like DNA and RNA, are made up of nucleotides and store genetic information in cells.

2. What is the length of DNA that can code for a particular protein?

• A. Chromosome
• B. Nucleotide
• C. Gene
• D. Ribosome

Correct answer: C

Rationale: The correct answer is C: Gene. A gene is a specific segment of DNA that contains the information necessary to produce a particular protein. Genes are responsible for coding proteins, and each gene carries the instructions for a specific protein. Chromosomes consist of many genes and are not a specific length that codes for a protein. Nucleotides are the building blocks of DNA and are not a length that codes for a protein. Ribosomes are cellular organelles involved in protein synthesis and do not directly code for proteins.

3. What is the primary function of the kidneys?

• A. To digest food
• B. To filter blood and produce urine
• C. To absorb nutrients
• D. To transport oxygen

Correct answer: B

Rationale: The primary function of the kidneys is to filter blood and remove waste products from the body, producing urine in the process. This function helps in maintaining the body's internal environment stable, a process known as homeostasis. Option A, 'To digest food,' is incorrect as digestion primarily occurs in the gastrointestinal system, not in the kidneys. Option C, 'To absorb nutrients,' is also incorrect because nutrient absorption mainly takes place in the intestines. Option D, 'To transport oxygen,' is incorrect as the lungs and circulatory system are responsible for oxygen transport, not the kidneys.

4. Which structure serves as the electrical stimulator of the cardiac muscle?

• A. The sinoatrial node
• B. The left ventricle
• C. The aorta
• D. The tricuspid valve

Correct answer: A

Rationale: The correct answer is the sinoatrial node. This node, also referred to as the pacemaker of the heart, is responsible for initiating the electrical impulses that stimulate cardiac muscle contractions. It plays a crucial role in setting the pace and rhythm of the heart's contractions. Choices B, C, and D (the left ventricle, the aorta, and the tricuspid valve, respectively) do not serve as the primary electrical stimulator of the cardiac muscle. While the left ventricle is a chamber of the heart that pumps oxygenated blood to the body, the aorta is the main artery that carries blood away from the heart, and the tricuspid valve is a one-way valve that ensures blood flows properly through the heart, none of these structures initiate the electrical impulses that cause the cardiac muscle to contract.

5. Which level of protein structure is defined by the folds and coils of the protein's polypeptide backbone?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary

Correct answer: B

Rationale: The correct answer is B: Secondary. The secondary structure of a protein is defined by the folding and coiling of the polypeptide backbone into structures like alpha helices and beta sheets. Secondary structure primarily involves interactions such as hydrogen bonding within the backbone. This level of protein structure is distinct from primary structure (A) which refers to the linear sequence of amino acids, tertiary structure (C) which involves the overall 3D arrangement of a single polypeptide chain, and quaternary structure (D) which pertains to the interaction between multiple polypeptide chains in a protein complex.

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