Nursing Elites

1. How does lymph move through the lymphatic vessels?

• A. By the pumping action of the heart
• B. Due to muscle contractions and breathing movements
• C. Through one-way valves within the vessels
• D. All of the above

Correct answer: C

Rationale: Lymph moves through the lymphatic vessels due to the presence of one-way valves within the vessels. These valves prevent the backflow of lymph and help propel the fluid forward as muscles contract and relax or due to breathing movements. Unlike blood circulation, the lymphatic system does not rely on the pumping action of the heart to move lymph. Choice A is incorrect because lymphatic circulation does not depend on the pumping action of the heart. Choice B is partly correct as muscle contractions and breathing movements do assist in propelling lymph, but the primary mechanism is the presence of one-way valves within the vessels, making choice C the most accurate answer. Choice D is incorrect as not all options listed contribute to how lymph moves through the lymphatic vessels.

2. What type of bond links amino acids together to form proteins?

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

Correct answer: D

Rationale: Amino acids are linked together by covalent bonds to form proteins. Specifically, the bond that links amino acids together is called a peptide bond, which is a type of covalent bond. The peptide bond forms between the amino group of one amino acid and the carboxyl group of another amino acid, resulting in the formation of a peptide chain. While hydrogen bonds, ionic bonds, and disulfide bonds are important for protein structure and stability, the primary bond responsible for linking amino acids in a protein chain is the covalent peptide bond. Hydrogen bonds are involved in maintaining the secondary structure of proteins, such as alpha helices and beta sheets. Ionic bonds and disulfide bonds contribute to tertiary and quaternary structures of proteins by stabilizing interactions between different parts of the protein or between different protein subunits, respectively.

3. Which cellular organelle is used for digestion to recycle materials?

• A. The Golgi apparatus
• B. The lysosome
• C. The centrioles
• D. The mitochondria

Correct answer: B

Rationale: The lysosome is the correct cellular organelle used for digestion to recycle materials. Lysosomes contain enzymes that break down waste materials, cellular debris, and ingested substances. This process helps in recycling nutrients and maintaining cellular homeostasis. The Golgi apparatus is involved in processing and packaging proteins, the centrioles play a role in cell division, and the mitochondria are responsible for energy production. However, none of these organelles are primarily used for digestion and recycling of materials within the cell.

4. What is the primary function of the respiratory system?

• A. To digest food
• B. To transport nutrients
• C. To exchange gases
• D. To regulate body temperature

Correct answer: C

Rationale: The correct answer is C: To exchange gases. The primary function of the respiratory system is to facilitate the exchange of gases, specifically oxygen and carbon dioxide, between the body and the environment. This process is essential for cellular respiration, where oxygen is taken in and carbon dioxide is removed. Choices A, B, and D are incorrect. Digesting food is primarily the function of the digestive system, transporting nutrients is the role of the circulatory system, and regulating body temperature is primarily managed by the integumentary system and the nervous system, not the respiratory system.

5. What is the primary difference between ionic and metallic bonding?

• A. Ionic bonds involve electron transfer, while metallic bonds involve electron sharing.
• B. Ionic bonds are weak and directional, while metallic bonds are strong and non-directional.
• C. Ionic bonds exist between metals and non-metals, while metallic bonds exist only between metals.
• D. Ionic bonds form discrete molecules, while metallic bonds form extended structures.

Correct answer: B

Rationale: Ionic bonds involve electron transfer, where one atom completely donates an electron to another, resulting in discrete molecules. On the other hand, metallic bonds are non-directional and strong, formed by a 'sea' of delocalized electrons shared among all metal atoms. This shared electron cloud allows for strong bonding throughout the entire material, making metallic bonds non-directional and strong compared to the directional and weaker nature of ionic bonds. Choice A is incorrect because metallic bonds do not involve electron sharing but rather the sharing of a sea of delocalized electrons. Choice C is incorrect as metallic bonds can also exist between metal atoms, not just between metals and non-metals. Choice D is incorrect because metallic bonds do not form discrete molecules but rather extended structures due to the sharing of electrons among all metal atoms.

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