Fluid Mosaic Model

What is the Fluid Mosaic Model?

A model describing the cell membrane as a fluid phospholipid bilayer with embedded proteins that can move.

What is the cell membrane mainly made of?

A phospholipid bilayer with proteins.

Why is the cell membrane called “fluid”?

Because phospholipids and proteins can move sideways within the layer.

Why is it called “mosaic”?

Because it contains different types of proteins embedded in the phospholipid bilayer.

What is a phospholipid bilayer?

Two layers of phospholipid molecules arranged tail-to-tail.

What are the two parts of a phospholipid?

A hydrophilic phosphate head and hydrophobic fatty acid tails.

What does hydrophilic mean?

“Water-loving” — attracted to water and able to interact with it.

Where are phospholipid heads located?

Facing the watery environments inside and outside the cell.

Where are phospholipid tails located?

Facing inward, away from water.

What are transport proteins?

Proteins that act as channels allowing specific substances to cross the membrane.

What is the function of receptor proteins?

They detect chemical signals (like hormones) and trigger a cellular response.

What are recognition proteins (glycoproteins)?

Proteins with carbohydrate chains used for cell identification

What is the function of glycoproteins?

Help the immune system distinguish “self” from “non-self” cells.

What are adhesion proteins?

Proteins that help cells stick together and attach to structures.

What is another role of membrane proteins?

Cell communication and signalling.

What does membrane permeability mean?

How easily substances can pass through the cell membrane.

Which molecules can easily pass through the membrane due to size?

Small molecules like water and urea.

Which molecules cannot easily pass through due to size?

Large molecules like glucose and amino acids.

Why can small molecules pass through the membrane more easily?

They can fit between phospholipid molecules.

Which molecules can easily pass through due to charge?

Uncharged molecules like oxygen and carbon dioxide.

Which molecules struggle to cross due to charge?

Charged ions like sodium (Na⁺) and potassium (K⁺).

What is solubility?

How easily a substance dissolves in a solvent (like the membrane environment).

Why do hydrophobic molecules cross the membrane more easily?

They dissolve in the lipid tails of the bilayer.

Why do hydrophilic molecules struggle to cross the membrane?

They cannot pass easily through the hydrophobic lipid core.

What determines whether a molecule can cross the membrane?

Size, charge, and solubility.

What is the main function of the cell membrane?

To control what enters and leaves the cell.

What role does the membrane play in communication?

Receptor proteins allow cells to respond to signals like hormones.

What best describes the Fluid Mosaic Model?

Fluid phospholipid bilayer with proteins

What is the main structural component of the membrane?

Lipids and proteins

What is the function of transport proteins?

Allow substances to cross membrane

What do receptor proteins do?

Detect signals

What are glycoproteins used for?

Cell identification

What is the correct structure of a phospholipid?

One head and two tails

Which part of a phospholipid is hydrophilic?

Phosphate head

Which molecules pass easily due to size?

Water

Which molecules are blocked due to size?

Amino acids

Which molecules pass easily due to charge?

Oxygen

Which molecules struggle due to charge?

Sodium ions

What is the membrane most permeable to?

Small uncharged molecules

Why do hydrophobic molecules pass easily?

They dissolve in lipid tails

What mainly affects membrane permeability?

Size, charge, and solubility

What is the role of adhesion proteins?

Help cells stick together

The cell membrane is rigid and fixed in place. - T/F

FALSE

The Fluid Mosaic Model describes a dynamic membrane. - T/F

TRUE

The membrane is made of a phospholipid bilayer. - T/F

TRUE

Phospholipid heads are hydrophobic. - T/F

FALSE

Phospholipid tails are hydrophobic. - T/F

TRUE

Transport proteins help substances move across the membrane. - T/F

TRUE

Receptor proteins respond to chemical signals. - T/F

TRUE

Glycoproteins help the immune system recognise cells. - T/F

TRUE

Only small molecules can cross the membrane easily. - T/F

TRUE

Charged ions cross the membrane easily without help. - T/F

FALSE

Oxygen and carbon dioxide cross the membrane easily. - T/F

TRUE

Glucose crosses the membrane easily without assistance. - T/F

FALSE

Solubility affects how easily substances cross the membrane. - T/F

TRUE

Hydrophilic molecules cross the lipid bilayer easily. - T/F

FALSE

The membrane controls what enters and leaves the cell. - T/F

TRUE

All molecules can freely cross the membrane. - T/F

FALSE

Cell membranes are identical in all cell types. - T/F

FALSE

Membrane proteins are involved in communication. - T/F

TRUE