Nursing Elites

1. A circular bandage has a diameter of 6cm. What is the area covered by the bandage (area of a circle = πr^2)?

• A. 9Ï€ cm^2
• B. 18Ï€ cm^2
• C. 27Ï€ cm^2
• D. 36Ï€ cm^2

Correct answer: B

Rationale: Divide the diameter (6cm) by 2 to find the radius (3cm). Substitute into the formula and multiply by π to get 18π cm^2.

2. What are isotopes?

• A. Atoms of the same element with different numbers of protons.
• B. Atoms of the same element with different numbers of neutrons.
• C. Atoms of different elements with the same number of protons.
• D. Atoms of different elements with the same number of electrons.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that isotopes have the same atomic number (Z) but different mass numbers (A). For example, carbon-12 (¹²C), carbon-13 (¹³C), and carbon-14 (¹⁴C) are all isotopes of carbon. They all have six protons in their nuclei, but they have different numbers of neutrons: carbon-12 has six neutrons, carbon-13 has seven neutrons, and carbon-14 has eight neutrons.

3. Homologous structures are similar structures in different organisms that have a common evolutionary origin. An example is:

• A. Butterfly wings and bird wings (analogous structures with different origins)
• B. The arm of a human, the wing of a bat, and the flipper of a whale
• C. The eyes of an octopus and a human (convergent evolution with different origins)
• D. The stinger of a bee and the barb of a cactus (unrelated structures)

Correct answer: B

Rationale: Rationale: Homologous structures are similar structures found in different organisms that share a common evolutionary origin. In this case, the arm of a human, the wing of a bat, and the flipper of a whale are all examples of homologous structures. Despite serving different functions in these organisms, they share a common underlying structure due to their evolutionary relationship. These structures are evidence of a shared ancestry and are modified over time to suit the specific needs of each species. Option A (Butterfly wings and bird wings) refers to analogous structures, which have similar functions but different evolutionary origins. Option C (The eyes of an octopus and a human) describes convergent evolution, where similar traits evolve independently in different species due to similar environmental pressures. Option D (The stinger of a bee and the barb of a cactus) refers to unrelated

4. Half-life refers to the characteristic time it takes for:

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: The correct answer is D: An isotope to decay by half of its initial quantity. The half-life of a substance is the time it takes for half of the initial quantity of radioactive atoms to decay. This is a characteristic property of each radioactive isotope and is used to determine the rate of decay of a substance. Option A is incorrect because radioactive intensity does not completely disappear in half-life, it only decreases by half. Options B and C are unrelated to the concept of half-life and do not accurately describe its definition.

5. What happens when a protein unfolds?

• A. Activation
• B. Denaturation
• C. Renaturation
• D. Folding

Correct answer: B

Rationale: Rationale: - Activation (Option A) refers to the process of initiating or increasing the activity of a molecule, such as an enzyme. Protein unfolding does not involve activation. - Denaturation (Option B) is the correct answer. Denaturation refers to the process by which a protein loses its three-dimensional structure, leading to the disruption of its function. This can be caused by factors such as heat, pH changes, or chemicals. - Renaturation (Option C) is the process by which a denatured protein regains its native structure and function. Protein unfolding is the opposite of renaturation. - Folding (Option D) is the process by which a protein assumes its functional three-dimensional structure. Unfolding is the reverse process of folding, not folding itself.

6. What type of molecule forms the cell membrane and controls what enters and exits the cell?

• A. Proteins
• B. Carbohydrates
• C. Lipids
• D. Nucleic acids

Correct answer: C

Rationale: The correct answer is C: Lipids. The cell membrane is primarily composed of a double layer of lipids called phospholipids. These phospholipids have a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, which arrange themselves to form a barrier that controls the passage of substances in and out of the cell. While proteins are also present in the cell membrane and play important roles in transport and cell signaling, lipids are the main structural component responsible for the selective permeability of the membrane. Carbohydrates are typically found on the outer surface of the membrane and are involved in cell recognition and communication. Nucleic acids are not a major component of the cell membrane; they are primarily responsible for storing and transmitting genetic information within the cell.

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