Movement of substances

What is diffusion

It is the net movement of particles from a region of higher concentration to a region of lower concentration. (down a concentration gradient)

Factors affecting rate of diffusion

Surface area to volume ratio, Diffusion distance, Concentration gradient, Temperature, molecular size

How does higher temperature affect rate of diffusion

At a higher temperature, particles gain more kinetic energy and move faster, higher rate of diffusion

What is osmosis

It is the net movement of water molecules from a region of higher water potential to a region of lower potential, through a partially permeable membrane.

What is water potential

Measure of tendency of water molecules to move from one place to another

Hypertonic, hypotonic, isotonic?

Hypertonic = Solution w lower water potential than the other

Hypotonic = Higher water potential than the other

Isotonic = Same water potential as the other

Factors affecting rate of osmosis

Water potential gradient, Distance water molecules need to move, Surface area-to-volume ratio

What is active transport

Process in which energy is used to move particles of a substance against a membrane across its concentration gradient. (from a region of lower concentration to higher concentration)

Where does energy come from for active transport

Every cell produces its own store of Adenosine triphosphate molecules (ATP idk if need to know or not) that supply their own energy by RESPIRATION IN MITOCHONDRIA.

What happens when plant cells are placed in a dilute solution

1. cell sap has lower water potential ,water molecules enter cell by osmosis

2. vacuole expands in volume and pushes cell membrane and cytoplasm towards cell wall.

3. Cell becomes TURGID

animal cells in a dilute solution

1. cytoplasm has a lower water potential, water enter cytoplasm by osmosis

2. cell expands in volume

3. plasma membrane is delicate and unable to prevent further expansion, cell BURSTS

plant cell in a concentrated solution

1. cell sap has a higher water potential, water molecules leaves vacuole by osmosis

2. Vacuole shrinks in size and plasma membrane and cytoplasm shrinks away from cellulose cell wall

3. Cell becomes PLASMOLYSED

animal cell in a concentrated solution

1. Cytoplasm has a higher water potential, water molecules leaves cytoplasm by osmosis

2. Cell shrinks in volume

3. Cell becomes CRENATED