Front

What is the structure of a lipid bilayer?

Back

A lipid bilayer consists of two layers of phospholipids, with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward, creating a barrier that separates the cell from its environment.

Front

What does hydrophobic mean?

Back

Hydrophobic refers to substances that do not mix with water; in the context of cell membranes, it describes the fatty acid tails of phospholipids that face each other and exclude water.

Front

What role do proteins play in the cell membrane?

Back

Proteins in the cell membrane function as gatekeepers, controlling the entry and exit of substances, and serve as enzyme receptors that facilitate communication and signaling.

Front

Define plasma membrane.

Back

The plasma membrane is a flexible boundary of a cell that separates the cell from its surroundings, regulating what enters and exits the cell.

Tags

NGSS.MS-LS1-2

Front

What is homeostasis?

Back

Homeostasis is the state of equilibrium in a biological system, where internal conditions remain stable despite external changes.

Tags

NGSS.HS-LS1-3

Front

What are the components of the cell membrane?

Back

The cell membrane is primarily composed of phospholipids, proteins, cholesterol, and carbohydrates.

Front

What is the function of cholesterol in the cell membrane?

Back

Cholesterol helps to stabilize the fluidity of the cell membrane, making it less permeable to very small water-soluble molecules that might otherwise pass freely through.

Front

What are channel proteins?

Back

Channel proteins are integral membrane proteins that form pores in the membrane, allowing specific molecules or ions to pass through.

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 concentration gradient.

Front

What is the significance of carbohydrate chains on the cell membrane?

Back

Carbohydrate chains attached to proteins and lipids on the cell membrane serve as recognition sites for cell signaling and communication.