Unit 1 - Section 2 - Exchange Across Plasma Membranes

Front 1

Diffusuion

Back 1

The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient.

Front 2

Factors affecting the rate of diffusion:

Back 2

The concentration gradient, The thickness of the exchange surface and the surface area.

Front 3

Osmosis

Back 3

The diffusion of water molecules across a partially permeable membrane, from an area of high water potential to an area of low water potential.

Front 4

If two solutions have the same water potential they're said to be ..1..

Back 4

1=isotonic

Front 5

If a cell is placed in a solution that has a higher water potential, water will move into the cell by osmosis. Solutions with a higher water potential compared with inside the cell are called ...

Back 5

Hypotonic

Front 6

An animal cell inside a hypotonic solution will

Back 6

Swell and eventually burst

Front 7

If a plant cell is placed inside a hypotonic solution

Back 7

The vacuole will swell and the vacuole and cytoplasm will push up against the cell wall. This causes the cell to become turgid.

Front 8

If a cell is placed in a solution that has a lower water potential, water will move out by osmosis. Solutions with a lower water potential compared with inside the cell are called ...

Back 8

Hypertonic

Front 9

An animal cell inside a hypertonic solution will

Back 9

Shrink

Front 10

If a plant cell is placed inside a hypertonic solution

Back 10

It will become Flaccid. The cytoplasm and plasma membrane will eventually pull away from the cell wall(This is Plasmolysis)

Front 11

Carrier proteins

Back 11

Move large molecules(polar molecules and ions) into or out of the cell, down a concentration gradient.

Front 12

Channel proteins

Back 12

Form pores in the membrane for smaller ions and polar molecules to diffuse through, down their concentration gradient.

Front 13

Active transport

Back 13

Uses energy to move molecules and ions across plasma membranes, against a concentration gradient.

Front 14

Some molecules are too large to be moved my carrier proteins, so they use ..1.. It works by ..2..

Back 14

1=Endocytosis
2=A cell surrounding a substance with a section of its plasma membrane. Then the membrane pinches off to form vesicles inside the cell containing the ingested substance.

Front 15

Some substances produced need to be released by the cell. This is done by ..1.. It works by

Back 15

1=Exocytosis
2=Vesicles containing these substances pinch off from the sacs of the golgi apparatus and move towards the plasma membrane, The vesicles fuse with the plasma membrane and release their contents outside the cell.