Cell Membrane Overview and Composition

Which type of molecule primarily forms the boundary of the cell membrane?

What is the main purpose of cholesterol in the cell membrane?

Which statement best describes the term 'selectively permeable' as it relates to the cell membrane?

What role do carbohydrates play in the cell membrane?

What is the main function of proteins in the cell membrane?

What is the primary direction of movement for molecules during passive transport?

Which of the following processes requires energy, such as ATP, to occur?

In facilitated diffusion, what is essential for molecules to cross the plasma membrane?

Which type of transport specifically refers to the movement of water molecules?

What outcome is achieved when a solution reaches equilibrium?

What describes the movement of molecules during active transport?

Which of the following is NOT an example of passive transport?

What is the difference between diffusion and facilitated diffusion?

Cell Membrane Overview

Cell membrane is also known as the plasma membrane.
It is sometimes called the phospholipid bilayer.

Cell Membrane Composition

Composed of phospholipids, proteins, and carbohydrates.
Phospholipids are arranged in a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Phospholipids

Create the boundary of the cell membrane.
Composed of two parts:
- Hydrophilic head (attracted to water)
- Hydrophobic tail (repelled by water, contains fatty acids)
This arrangement creates a barrier that controls what moves in and out of the cell.

Proteins

Help transport materials in and out of the cell.
Various types of proteins exist embedded within the membrane.
- Channel proteins are always open to permit certain materials to passively move through the membrane.
- Carrier proteins help move materials across the membrane.

Carbohydrates

Signal and identify particles outside the cell.
Act like antenna for the cell.

Cholesterol

Keeps the membrane fluid.
Prevents lipids from sticking together.

Functions of the Cell Membrane

Boundary: Acts as a flexible and fluid boundary, allowing the cell to change shape.
Homeostasis: Helps maintain homeostasis by controlling what enters and leaves the cell. Transport materials in and out of the cell to maintain balance.
Selectively Permeable: It only allows certain molecules to pass through easily (like water) while others (like sugars) can't pass through easily.

What Enters and Leaves the Cell

Enter: Food, water, oxygen
Leave: Waste, carbon dioxide

Explore the structure and function of the cell membrane, also known as the plasma membrane. This quiz covers its composition, focusing on phospholipids, proteins, and carbohydrates, and how they function to maintain cellular integrity and regulate what enters and exits the cell.