movement in the cell

Question 1

what is the semi permeable (selectively permeable) layer which protects the cell and determines what goes in and out?

Answer 1

the lipid bilayer cell membrane.

Question 2

what are the two ways which particles get through the cell membrane?

Answer 2

active transport and passive transport (look in notes for picture)

Question 3

what does passive transport mean?

Answer 3

Does not require energy for particles to move across a cell membrane
Molecules travel with an concentration gradient from high to low. only small particles use passive transport.
Ex; Diffusion and Osmosis

Question 4

what is osmosis and diffusion?

Answer 4

diffusion is when a particle moves from an area of high concentration to low concentration between the cell membrane.
osmosis is when water moves through the cell membrane from high to low concentration.

Question 5

what does active transport mean?

Answer 5

When cells use ATP energy to move molecules across a membrane from low concentration to high concentration Molecules travel against the concentration gradient. only large particles use active transport.

Proteins are also embedded in the cell membrane
Carrier proteins
Carry specific substances (amino acids, sugars) across cell membrane (usually large molecules)
Channel proteins
Allow charged ions to pass through cell membranes (sodium, potassium, calcium, etc.)
Ex; Sodium potassium pump Carrier proteins

Question 6

what does concentration gradient mean?

Answer 6

A difference between areas of high concentration and areas of low concentration.

Question 7

what are the 3 universal solvents?

Answer 7

Solvent - substance that does the dissolving
Solute - substance dissolved in a solution
solution - mixture of solvent and solute

Question 8

what are the 3 solution types?

Answer 8

Hypotonic Solution
Solution: Pure water
Change in size: Expands

Isotonic solution
Equal Concentration
Change in size: Stays the same
Does not always mean 50/50. molecules constantly move.

Hypertonic solution
Solution: salt water
Change in size: shrinks
Water moves based on the solute concentration

Question 9

what is homeostasis?

Answer 9

A stable level of internal conditions (I.E sugar levels, oxygen levels, water, etc)

Question 10

how do things like diffusion and osmosis help us maintain homeostasis?

Answer 10

By moving nutrients into the cell and waste out of the cell.