Nursing Elites

1. Which type of passive transport uses proteins that change shape to move a target molecule through the membrane?

• A. Diffusion
• B. Carrier proteins
• C. Channel proteins
• D. None of the above

Correct answer: B

Rationale: The correct answer is B: Carrier proteins. Carrier proteins are involved in facilitated diffusion, a type of passive transport where specific target molecules are moved across the membrane with the help of proteins that change shape. These carrier proteins bind to the target molecule on one side of the membrane, undergo a conformational change, and then release the molecule on the other side. This process is crucial for the selective transport of certain molecules that cannot pass through the membrane by simple diffusion. Choices A and C are incorrect because diffusion and channel proteins do not involve proteins that change shape to transport target molecules selectively. Choice D is incorrect as carrier proteins fit the description provided in the question.

2. How are molecules of water bonded to each other?

• A. Ionic
• B. Covalent
• C. Hydrogen
• D. Molecular

Correct answer: C

Rationale: Water molecules are bonded to each other by 'hydrogen' bonds. These bonds are not as strong as covalent bonds, which hold the atoms within each water molecule together (Choice B). Ionic bonds (Choice A) involve the transfer of electrons between atoms, which is not the case in water molecules. The term 'molecular' (Choice D) is too general and doesn't specifically describe the type of bond between water molecules.

3. Which of the following molecules is an important component of the plasma membrane?

• A. Phospholipids
• B. Steroids
• C. Sugars
• D. Amino acids

Correct answer: A

Rationale: Phospholipids are indeed a crucial component of the plasma membrane. They have a unique structure with hydrophilic heads and hydrophobic tails, which allows them to form the lipid bilayer of the membrane. Steroids, sugars, and amino acids are not primary components of the plasma membrane. Steroids are a different type of lipid, sugars are often found in glycoproteins on the membrane surface, and amino acids are the building blocks of proteins, some of which are membrane proteins, but not the membrane itself.

4. A child is sick. They have a body temperature that exceeds 37ºC. The body senses this and begins to sweat in order to lower the temperature. What is this an example of?

• A. Positive feedback loop
• B. Negative feedback loop
• C. Both
• D. None of the above

Correct answer: B

Rationale: This is an example of a negative feedback loop. In a negative feedback loop, the body's response (sweating) works to counteract the initial stimulus of a high body temperature by cooling the body down. The goal is to return the body to homeostasis, maintaining a stable internal environment. Positive feedback loops amplify the initial stimulus rather than counteracting it, which is not the case here. Therefore, choices A and C are incorrect. Choice D is also incorrect as the situation described fits the characteristics of a negative feedback loop.

5. Which of the following is the structure of the male reproductive system that stores spermatozoa during the maturation process?

• A. vas deferens
• B. scrotum
• C. epididymis
• D. testicular artery

Correct answer: C

Rationale: The epididymis is the structure of the male reproductive system that stores spermatozoa during the maturation process. Sperm cells produced in the testes move to the epididymis, where they mature and become motile before being ejaculated. The vas deferens is responsible for transporting mature sperm to the urethra during ejaculation, the scrotum holds the testes and helps regulate their temperature for sperm production, and the testicular artery supplies blood to the testes. Therefore, choices A, B, and D are incorrect as they do not play a direct role in storing spermatozoa during the maturation process.

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