2.1.2: Lipids

Question 1

What is the structure that results from the tails of phospholipids moving away from water?

Answer 1

Phospholipid bilayer membrane structure

This structure forms the plasma membrane around cells and some organelles.

Question 2

What is the nature of the phosphate head in a phospholipid?

Answer 2

Hydrophilic

This hydrophilic nature enables the surface of the plasma membrane to stay in place.

Question 3

What important structures form on the membrane due to the phospholipid bilayer arrangement?

Answer 3

Carbohydrates forming important receptors (glycolipids)

Glycolipids are crucial for cell recognition and signaling.

Question 4

What is the defining structural feature of sterols?

Answer 4

4 carbon rings and a hydroxyl group at one end

Sterols have both hydrophobic and hydrophilic regions.

Question 5

What role does cholesterol play in cell membranes?

Answer 5

Impacts fluidity

Cholesterol helps reduce fluidity at high temperatures and increase it at low temperatures.

Question 6

Fill in the blank: The _______ group is a component of phospholipids that is hydrophilic.

Answer 6

Phosphate

Question 7

What is a liposome?

Answer 7

A spherical vesicle composed of a lipid bilayer

Liposomes are often used in drug delivery systems.

Question 8

What is a micelle?

Answer 8

An aggregate of surfactant molecules

Micelles are formed in aqueous solutions and play a role in emulsifying fats.

Question 9

True or False: Cholesterol is a type of phospholipid.

Answer 9

False

Cholesterol is classified as a sterol, which is structurally different from phospholipids.

Question 10

What are the two regions of cholesterol?

Answer 10

• Hydrophobic region
• Hydrophilic region

This dual nature allows cholesterol to interact with both the lipid bilayer and the aqueous environment.