CH2/3 ozmosis, diffusion and transport through the membrane

Question 1

what is diffusion?

Answer 1

• the movement of molecules down the concentration gradient
• non polar and small molecules can freely diffuse across the plasma membrane

Question 2

why can water molecules move through the plasma membrane even though they are hydrophilic?

Answer 2

they pass through the membrane through special proteins called aquaporins

Question 3

what is tonicity?

Answer 3

the measure of the relative concentrationof solutes one either side of the plasma membrane

Question 4

why is protein mediated active transport needed?

Answer 4

for when there is a difference in concentration gradients of the substances inside and outside of the cell

Question 5

what does against the gradient need?

Answer 5

• energy (ATP)
• membrane proteins
  as it helps substances through

Question 6

what is facillitated diffusion?

Answer 6

it is a type of passive transport where molecules move through a phospholipid bilayer with the aid of a membrane protein

Question 7

what is simple diffusion?

Answer 7

the passive movement of molecules from areas of high concentration to areas of low concentration (down the concentration gradient)

Question 8

what is ozmosis?

Answer 8

the passive transport of a solvent (typically water) through a semi permeable membrane from a region of low solute to a region of high solute.

Question 9

what does hypertonic mean?

Answer 9

a solution with a higher concentration compared to another solution

Question 10

what does isotonic mean?

Answer 10

a solution with the same solute concentration when compared to another solution

Question 11

what does hypotonic mean?

Answer 11

a solution with a lower concentration when compared to another solution

Question 12

what are the elements of the plasma membrane and what do they do?

Answer 12

1. cholesterol - regulates fluidity
2. phospholipids - form the bilayer
3. glycoproteins - antenna that repel/release bacteria
   - a protein bound to a carbohydrate
4. peripheral proteins - communication
   - a protein that is temporarily attached to the plasma membrane
5. channel protein - pore - watermolecules or small ions pass through
6. carrier protein - transfer solutes across lipid bilayer by undergoing conformational changes

Question 13

what are the 3 types of proteins?

Answer 13

Integral protein – proteins that are a permanent part of the
membrane
Transmembrane protein – integral proteins that span the entire bilayer
**Peripheral protein **– are temporarily attached to the
plasma membrane

Question 14

what is a carrier protein?

Answer 14

• attatch to a substancethat is being transported
• undergoes conformational change to push substance down the concentration gradient

Question 15

what is a protein channel?

Answer 15

• pores or holes in the membrane
• help move water molecules or small ions down their concentration gradient in or out of the cell

Question 16

what are phospholipids?

Answer 16

• maintains integrity and fluidity of cell membrane
• the main component of the plasma membrane
• ## hydrophyllic head/ hydrophobic tail

Question 17

amphipathic

Answer 17

a molecule with both hydrophobic and hydrophyllic components

e.g phospholipid

Question 18

plasma membrane

Answer 18

• semi permeable membrane
• controls what enters and exits the cell
• made up of phospholipids and has many molecules embedded in it

Question 19

what is passive transport?

Answer 19

the movement of molecules through a semipermeable membrane and down the concentration gradient without the input of energy
- no ATP

Question 20

what is the function of the plasma membrane?

Answer 20

it controls what can enter and exit the cell

Question 21

what is active transport?

Answer 21

movement of molecules across a semipermeable membrane that requires energy
- uses ATP
- used AGAINST the concentration gradient

Question 22

what does ATP stand for?

Answer 22

adenosine triphosphate

Question 23

what is exocytosis?

Answer 23

moves large substances out of the cell

Question 24

what is endocytosis?

Answer 24

moves large substancesinto a cell

Question 25

extra cellular?

Answer 25

outside the cell

Question 26

intracellular?

Answer 26

inside the cell

Question 27

solute?

Answer 27

a substance dissolved in solvent

Question 28

solution?

Answer 28

a liquid in which a solute is dissolved in a solvent, forming a solution

Question 29

solvent?

Answer 29

The term ‘solvent’ can be defined as a substance that has the ability to dissolve a given solute to form a solution with it.