bio concentration stuff

What is a concentration gradient?

The difference in concentration of a substance across space or a membrane.

What does equilibrium mean?

When concentrations are equal and there is no net movement of molecules.

What is dynamic equilibrium?

Molecules continue to move, but there is no net change in concentration.

What is diffusion?

The movement of molecules from high concentration to low concentration.

What type of transport is diffusion?

Passive transport.

What is passive transport?

Movement of substances without using energy (ATP).

What is simple diffusion?

Movement of small or nonpolar molecules directly through the membrane.

What is facilitated diffusion?

Diffusion using transport proteins to move substances across the membrane.

What is the role of channel proteins?

They form tunnels that allow specific molecules or ions to pass through.

What is the role of carrier proteins?

They bind to molecules and change shape to move them across the membrane.

What are leak channels?

Channels that are always open and allow ions to pass freely.

What are gated channels?

Channels that open or close in response to a signal.

What is active transport?

Movement of substances against the concentration gradient using ATP.

What molecule provides energy for active transport?

ATP.

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What is a hypotonic solution?

A solution with lower solute concentration than the cell.

What happens to a cell in a hypotonic solution?

Water enters the cell and it may swell or burst.

What is a hypertonic solution?

A solution with higher solute concentration than the cell.

What happens to a cell in a hypertonic solution?

Water leaves the cell and it shrinks.

What is an isotonic solution?

A solution with equal solute concentration as the cell.

What happens to a cell in an isotonic solution?

No net movement of water; the cell stays the same size.

What is plasmolysis?

When a plant cell membrane pulls away from the cell wall due to water loss.

What is cytolysis?

When an animal cell bursts from too much water entering.

What does turgid mean?

A plant cell that is firm and swollen with water.

What does flaccid mean?

A plant cell that is limp due to water loss.

What is endocytosis?

The process of bringing materials into the cell using vesicles.

What is exocytosis?

The process of releasing materials from the cell using vesicles.

What is osmoregulation?

The control of water and solute balance in an organism.

How do freshwater fish regulate water?

They gain water by osmosis and excrete dilute urine.

What is hyponatremia?

A condition where sodium levels in the blood are too low due to excess water.