osmosis, diffusion ect.

Question 1

what is cell membrane

Answer 1

also known as plasma membrane. it controls the movement of food, oxygen and water products out of the cell. it only allows some particles to pass through thus it is a semi-permeable mebrane

Question 2

what is cell membrane made out of?

Answer 2

the cell membrane is mostly made of lipids (phospholipids) but is also scatted with protein, colesterol and carbohydrate chains.

Question 3

diffusion

Answer 3

the net movement of the particles from a area of high concentration to an area of low concentration. moves down/along their concentration gradiant. does not require energy

Question 4

diffusion in cells

Answer 4

the concentation of a molecule is greater outside a cell than inside the cell then, on average, more molecule will randomly enter the cell than leave the cell.

Question 5

what is equilibrium

Answer 5

particles tend naturally to diffuse untill they take up the avalible space evenly.
at this point the rate at which individual molecules wnter and leave will be equal and equilibruim is siadto have been reached

Question 6

what is facilitated diffusion

Answer 6

the same as normal diffusion execpt it involes the use of protein.

Question 7

osmosis

Answer 7

a special type of diffusion which involes the net movement of water molecules acros a semi-permeable membrane into a region of higher solute concentration.
most solutes can’t readily ceross membrane because they are to large to fit. so water molecules are drawn across to the concentration difference.

Question 8

osmosis in cells

Answer 8

cell memranes are permeable to water so the environment the cell is exposed to can have dramatic effects on the cell.
the environment of the cell could contain a higher. lower or equal concentration of solutes as the cell.

Question 9

isotonic solutins

Answer 9

‘iso’ means’the same’. When the concentration of solutes is the same outside the cell as in, the solution is said to isotonic.
water molecules move into and out of the cell at thesame rate. there is no net (overall) movement of water.

Question 10

hypotonic solutions

Answer 10

hypo means below. when the concentration of solutes is lower outside the cell than in, the solution is said to be hypotonic.
water molecules move into the cell faster than they move out. there is a net movement of water into the cell.

Question 11

hypertonic

Answer 11

hyper means above. when the concentration of solutes is higher outside the cell than in the solution is said to be hypertonic.
water molecules move out of the cell faster than they move in. ther is a net movement of water out of the cell.

Question 12

what is plasmolysis

Answer 12

plasmolysis occurs when the plant cells are placed in a hypertonic environment and water is drawn out of the cells. the large vocuole shrink
the cell membrane begins to pull away from the cell wall

Question 13

active tansport

Answer 13

active transport, by contrast, is: the net movement of particles across a cell membrane from a region of low concentration into a region of higher concentration with the assistance of protein carries and energy( as ATP)

Question 14

endocytosis

Answer 14

will invole substances coing into the cell in such a way that membranefrom the cell

Question 15

exocytosis

Answer 15

involves substances will be in a ‘bubble’ of memrane that will fuse with the cell membrane to release the contents.