Directed Reading: Exchange with the Environment

In what order would the figures demonstrate endocytosis?

B, A, C

In what order would the figures demonstrate exocytosis?

C, A, B

How does the movement of materials across the cell membrane relate to an organism's survival?

The movement of materials helps keep cells healthy so they can divide. Cell division then allows organisms to grow and repair injuries.

particles moving across a cell membrane without using energy

c. passive transport

two examples of passive transport

d. diffusion and osmosis

The movement of particles from areas of high concentration to areas of low concentration is called

diffusion

what a cell needs to transport particles by active transport

e. energy

A large particle can enter a cell by an active-transport process called

endocytosis

A large particle can leave the cell by an active-transport process called

exocytosis

The fluids that surround and fill a cell are made mostly of

water

passageways in a cell membrane

a. channels

the movement of particles from an area of low concentration to an area of high concentration across a cell membrane

b. active transport

Why is osmosis important to cell functions?

Osmosis helps maintain a balance of all the concentrated particles within the cell--Cells need water to survive

What happens to a cell during the process of exocytosis

The cell forms a vesicle around the large particle and carries the particle to the cell membrane. The vesicle fuses with the membrane and releases the particle outside.

What happens to a cell during the process of endocytosis?

The cell surrounds a large particle and encloses it in a vesicle to bring the particle into the cell.

Describe what would happen if you put red blood cells into a salty solution

The water will move out of the red blood cells to where water molecules are less concentrated in the salty solution. The cells will shrivel up.

Describe what happens to a wilted plant when it is watered.

Through the process of osmosis, water moves into the plant cells, which makes the plant firm again

Describe what happens in osmosis.

Water particles move fom high concentration to where they are less concentrated

Water is made up of particles called

molecules

The diffusion of water through a semipermeable membrane is called

osmosis

The channels in a cell membrane are made up of

proteins