Nursing Elites

1. 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.

2. Which of the following arrangement is seen in the plasma membrane?

• A. Lipids with embedded proteins
• B. An outer lipid layer and an inner lipid layer
• C. Proteins embedded in lipid bilayer
• D. Altering protein and lipid layers

Correct answer: C

Rationale: The correct arrangement seen in the plasma membrane is proteins embedded in the lipid bilayer. The plasma membrane is composed of a lipid bilayer with embedded proteins. These proteins perform various functions such as transport, signaling, and structural support within the cell membrane. This arrangement allows for the selective permeability of the membrane and facilitates communication between the cell and its environment. Choices A, B, and D are incorrect because the primary arrangement in the plasma membrane involves proteins being embedded in the lipid bilayer, not lipids with embedded proteins, an outer and inner lipid layer, or altering protein and lipid layers.

3. 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.

4. What organelle pushes water out of the cell?

• A. Lysosomes
• B. Vacuoles (contractile)
• C. Mitochondria
• D. Nucleus

Correct answer: B

Rationale: The correct answer is B: Vacuoles (contractile). Vacuoles (contractile) are responsible for expelling excess water out of the cell. Lysosomes are involved in the digestion and removal of waste materials, mitochondria are the powerhouse of the cell involved in energy production, and the nucleus contains the cell's genetic material but does not play a role in pushing water out of the cell.

5. What happens to glucose during glycolysis?

• A. Its energy is entirely lost.
• B. It splits into molecules of pyruvic acid.
• C. It is stored in NADH.
• D. It joins with molecules of citric acid.

Correct answer: B

Rationale: During glycolysis, glucose undergoes a series of enzymatic reactions in the cytoplasm of the cell, resulting in its breakdown into two molecules of pyruvic acid. This process also generates ATP and NADH as energy carriers. Choice A is incorrect because glucose is not entirely lost, but rather converted into other molecules. Choice C is incorrect because NADH is a product of glycolysis, not a storage form for glucose. Choice D is incorrect as glucose does not join with molecules of citric acid during glycolysis, but rather in subsequent stages of cellular respiration.

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