Biology: Homeostasis, Passive and Active Transport Methods

What is homeostasis?

The stable level of internal conditions maintained by living organisms.

What can happen if homeostasis is not maintained?

Disease or death may occur.

What is passive transport?

The movement of molecules across the cell membrane without the use of energy.

Name the four types of passive transport.

Diffusion, osmosis, facilitated diffusion, and ion channel diffusion.

What is diffusion?

The movement of molecules from an area of high concentration to an area of low concentration through the cell membrane.

What is required for diffusion to occur?

A concentration gradient.

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What can happen if too much water moves into a cell?

The cell can burst in a process called cytolysis.

What is turgor pressure?

The pressure exerted on the cell walls in plants due to water intake.

What is facilitated diffusion?

A type of passive transport where molecules move from high to low concentration through carrier or channel proteins.

Why is facilitated diffusion necessary?

Because some molecules are too large or not lipid-soluble enough to pass through the cell membrane on their own.

What are ion channels?

Protein channels that allow specific ions to pass through the cell membrane.

What is active transport?

The movement of molecules across the cell membrane using energy, moving from low to high concentration.

What are protein pumps?

Proteins embedded in the cell membrane that help move molecules against the concentration gradient.

What is the sodium-potassium pump?

A type of protein pump that moves sodium out of the cell and potassium into the cell.

What is endocytosis?

The process of vesicles moving into the cell, enclosing materials as the cell membrane folds inward.

What is exocytosis?

The process of vesicles moving out of the cell by fusing with the cell membrane.

What is a hypertonic solution?

A solution with a higher solute concentration outside the cell, causing the cell to shrink.

What is a hypotonic solution?

A solution with a lower solute concentration outside the cell, causing the cell to expand.

What is an isotonic solution?

A solution where solute concentrations are equal inside and outside the cell, resulting in no net movement.

What is the role of ATP in active transport?

ATP provides the energy required for molecules to move against their concentration gradient.

What happens during plasmolysis?

The cell membrane shrinks away from the cell wall in plants due to loss of water.

How do carrier proteins work in facilitated diffusion?

They bind to specific molecules, change shape, and release the molecule on the other side of the membrane.

What is the significance of a concentration gradient?

It drives the movement of molecules during diffusion and osmosis.

What is cytolysis?

The bursting of a cell due to excessive water intake.

What is the function of vesicles in cellular transport?

To transport large quantities or large molecules that cannot pass through the cell membrane.