Question 1

Which of the following best describes how phospholipids arrange themselves in a cell membrane?

Accepted Answer

Phospholipids form a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Question 2

What is the primary reason phospholipids form a bilayer in aqueous environments?

Accepted Answer

Hydrophilic heads interact with water, while hydrophobic tails avoid water.

Question 3

Which property of the phospholipid bilayer allows it to act as a selective barrier for the cell?

Accepted Answer

The hydrophobic core restricts passage of polar molecules, while allowing nonpolar molecules to diffuse.

Question 4

A scientist adds a drop of oil to a beaker of water containing phospholipids. What will most likely happen to the phospholipids?

Accepted Answer

They will form a bilayer with hydrophobic tails facing the oil.

Question 5

Which of the following best explains the role of hydrophilic heads in the phospholipid bilayer?

Accepted Answer

They interact with the aqueous environment inside and outside the cell.

Question 6

Why do hydrophobic tails of phospholipids face each other in the bilayer?

Accepted Answer

They avoid contact with water, minimizing their exposure to the aqueous environment.

Question 7

Which of the following scenarios best illustrates the amphipathic nature of phospholipids?

Accepted Answer

Phospholipids form micelles with hydrophobic tails inside and hydrophilic heads outside.

Question 8

A mutation causes the hydrophilic head of a phospholipid to become nonpolar. What is the most likely effect on membrane formation?

Accepted Answer

The phospholipids will not form a stable bilayer in water.

Question 9

Which of the following best describes the arrangement of phospholipids in the cell membrane?

Accepted Answer

Hydrophilic heads face both the extracellular fluid and the cytoplasm, while hydrophobic tails face each other.

Question 10

Which of the following is a direct consequence of the phospholipid bilayer structure for cell function?

Accepted Answer

It creates a semi-permeable barrier, regulating the movement of substances.

Question 11

A patient is exposed to a toxin that disrupts the hydrophobic interactions in the cell membrane. What is the most likely outcome?

Accepted Answer

The bilayer will disintegrate, compromising cell integrity.

Question 12

Which of the following equations best represents the amphipathic nature of a phospholipid?

Accepted Answer

$$	ext{Phospholipid} = 	ext{Hydrophilic Head} + 	ext{Hydrophobic Tails}$$

Phospholipids and the Structure of Cell Membranes

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