Cell transport

What is homeostasis in relation to cell environment?

Homeostasis is the process by which body systems work together to keep the cellular environment constant, including maintaining a stable temperature and fluid concentration.

What is the primary structure of the cell membrane?

The cell membrane is primarily composed of a phospholipid bilayer, with hydrophilic heads facing outward and hydrophobic tails facing inward.

Explain the fluid mosaic model.

The fluid mosaic model describes the cell membrane structure as a mosaic of various molecules that move fluidly within the membrane.

What are the main functions of the cell membrane?

The main functions are to act as a physical barrier, regulate material passage, respond to stimuli, and provide support.

What does it mean when a cell membrane is said to be selectively permeable?

It means that the cell membrane allows certain ions and molecules to pass while restricting others.

Define simple diffusion.

Simple diffusion is a passive process where particles spread from areas of higher concentration to areas of lower concentration.

What is the difference between facilitated diffusion and active transport?

Facilitated diffusion is a passive process that moves substances along their concentration gradient, while active transport requires energy to move substances against their concentration gradient.

What is osmosis?

Osmosis is the diffusion of water through a selectively permeable membrane, moving from an area of low solute concentration to an area of high solute concentration.

What are the two types of vesicular transport?

Endocytosis, which includes pinocytosis (liquid uptake) and phagocytosis (solid uptake), and exocytosis, which is the release of substances from the cell.

Why do cells tend to be small?

Cells are small to maintain a high surface area-to-volume ratio, ensuring efficient exchange of materials across the cell membrane.

What role do proteins play in the cell membrane?

Proteins function as channels, carriers, receptors, and markers that facilitate communication and transport across the membrane.

What happens during endocytosis?

During endocytosis, the cell membrane engulfs external substances, forming a vesicle that brings materials into the cell.

Describe the movement of molecules within a cell.

Molecules and ions move within the cell mainly by diffusion, facilitated by structures like the endoplasmic reticulum and microtubules.