Unit 4

Front

What are phospholipids?

Back

Phospholipids are molecules that make up the cell membrane, consisting of a hydrophilic (water-attracting) 'head' and two hydrophobic (water-repelling) 'tails'. They form a bilayer that serves as a barrier to protect the cell.

Front

What is the fluid mosaic model?

Back

The fluid mosaic model describes the structure of the plasma membrane as a flexible layer made of lipid molecules with embedded proteins, allowing for movement and interaction.

Front

What is the primary function of the plasma membrane?

Back

The primary function of the plasma membrane is to regulate the movement of materials into and out of the cell, maintaining homeostasis.

Front

What is passive transport?

Back

Passive transport is the movement of substances across a cell membrane without the use of energy, relying on concentration gradients.

Front

What is facilitated diffusion?

Back

Facilitated diffusion is a type of passive transport that uses protein channels to help move substances across the plasma membrane.

Front

What is active transport?

Back

Active transport is the movement of substances against their concentration gradient, requiring energy (usually in the form of ATP) to occur.

Front

What role do proteins play in the plasma membrane?

Back

Proteins in the plasma membrane serve various functions, including acting as channels for transport, receptors for signaling, and enzymes for biochemical reactions.

Front

What is the difference between passive and active transport?

Back

Passive transport does not require energy and moves substances down their concentration gradient, while active transport requires energy to move substances against their gradient.

Front

What is osmosis?

Back

Osmosis is the diffusion of water across a selectively permeable membrane, moving from an area of lower solute concentration to an area of higher solute concentration.

Front

What is the significance of the semi-permeable nature of the plasma membrane?

Back

The semi-permeable nature of the plasma membrane allows the cell to control its internal environment by selectively allowing certain substances to enter or exit.