$\text{Phospholipid} = \text{Hydrophilic Head} + \text{Hydrophobic Tails}$

Question 1

Which part of a phospholipid is hydrophilic?

Accepted Answer

The phosphate head

Question 2

In a micelle formed by phospholipids, what type of environment is found at the center?

Accepted Answer

Hydrophobic

Question 3

Which of the following best describes the arrangement of phospholipids in a biological membrane?

Accepted Answer

Phospholipids form a bilayer with hydrophilic heads facing the aqueous environment and hydrophobic tails facing inward

Question 4

Which type of protein is embedded within the phospholipid bilayer and spans the membrane?

Accepted Answer

Integral protein

Question 5

What is the primary function of cholesterol (labeled as '6' in the membrane diagram) in the plasma membrane?

Accepted Answer

It increases membrane fluidity and stability

Question 6

If a cell is placed in a hypotonic solution, which region of the phospholipid bilayer will interact most with the external environment?

Accepted Answer

Hydrophilic heads

Question 7

Which of the following molecules can easily pass through the hydrophobic core of the phospholipid bilayer without the help of a protein?

Accepted Answer

O$_2$

Question 8

A mutation causes a protein to lose its ability to anchor to the membrane. What type of protein is most likely affected?

Accepted Answer

Peripheral protein

Question 9

Which part of the phospholipid is labeled as '1' in the diagram and what is its chemical property?

Accepted Answer

Phosphate head; hydrophilic

Question 10

In the context of membrane proteins, which statement is true about integral proteins?

Accepted Answer

They span the entire membrane and are embedded within the bilayer

Question 11

Which environment would the hydrophobic tails of phospholipids prefer?

Accepted Answer

Nonpolar interior of the membrane

Question 12

A micelle can carry which type of molecule in its center?

Accepted Answer

Hydrophobic molecules

Question 13

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

Hydrophilic heads interact with water while hydrophobic tails avoid water

Question 14

Which region of the membrane is most likely to contain carbohydrate chains involved in cell recognition?

Accepted Answer

Extracellular surface

Question 15

If a toxin disrupts the hydrophobic interactions in a membrane, what is the most likely consequence?

Accepted Answer

The membrane loses its integrity and may disassemble

Question 16

Which equation best represents the amphipathic nature of a phospholipid?

Accepted Answer

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

Question 17

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Energy storage

Question 18

A patient has a genetic defect in a membrane protein that acts as a channel. What is the most likely result?

Accepted Answer

Impaired facilitated diffusion of specific ions or molecules

Question 19

Which of the following best describes the environment outside of a micelle formed in water?

Accepted Answer

Hydrophilic

Question 20

Which labeled region in the membrane diagram is most likely to be hydrophobic?

Accepted Answer

Region 2 (fatty acid tails)

Phospholipids and Biological Membranes: Structure and Function

Study Guide - Practice Questions