cells 3

Question 1

What is the plasma membrane? what does it do?

Answer 1

-in eukaryotic cell and organelles
-regualates substance movement
-partiallu permeable(some molecules not all)

Question 2

What is meant by the term fluid mosaic?

Answer 2

-arrangment of molecules
-fluid- constanlty moving

Question 3

What is the arrnagment of phospolipids in the bilayer?
what do they do?

Answer 3

-only allow non polar molecules to pass through
-phophate head-exterior
-hydrocarbon tails-interior

Question 4

What is cholesterol? what does it do?

Answer 4

-lipid
-restricts movement/fluidity
-maintain cell shape

Question 5

what are the 2 types of protiens and what is their structure?

Answer 5

intergal-span the bilayer
peripheral-dont span bilayer

Question 6

what do peripheral protiens do?

Answer 6

-create receptors(glycolipids and glycoprotiens)
-mechanical support

Question 7

what do intergral protiens do?

Answer 7

-carrier and channel protiens
-allow polar large molecules to enter the cell

Question 8

function and structure of channel protiens

Answer 8

-contain water
-allow polar moelcules to diffuse through

Question 9

funstion and structure of channel protiens

Answer 9

-binds to the large molecules, changes shape to transport, and release on the other side

Question 10

properties of the cell membrane

Answer 10

-receptors for hormone signals
-reguakting solute movement
-identifiying solutes
-isolating cell from outside environment
-providing cell structure

Question 11

What is simple diffusion and where does it happen?

Answer 11

-passive
-for small non polar molecules
-through the fatty acid tails

Question 12

what is faciliated diffusion and where does it happen?

Answer 12

-passive
-large polar molecules
-through intergral protiens

Question 13

Definition of diffusion?

Answer 13

-the net movement of molecules between an area of higher concentration to an area of lowe concentration down a concentration gradients until equilibrium is reached

Question 14

Things that effect diffusion

Answer 14

-size of molecule
-size of concentration gradient
-amount of intergal protiens
-diffusion distance
-temperature

Question 15

What is the definition of osmosis

Answer 15

• the movement of water from an area of a higher water potential to lower water potential across a partially permeable membrane

Question 16

what is the sign for water potenital? waht the is measurement for water potential

Answer 16

-see book and kPa

Question 17

what is the water potentail for pure water?

Answer 17

-zero

Question 18

what happens when solutes become dissolved in water?

Answer 18

-it becomes negative- lower water potential

Question 19

What does isotonic mean?

Answer 19

the waterpotential in the cell and the solution is the same

Question 20

what does hypertonic mean and what happens?

Answer 20

when the water potential in the solution is more negative that in the cell ( cell will shrivel up)

Question 21

what is hypotonic and what does it mean?

Answer 21

-when the water potential in the solution is higher than inside the cell- cell will swell and burst

Question 22

why do cells bot burst in plant cells ?

Answer 22

-beacuse of their cell wall

Question 23

What is the definition of active transport?

Answer 23

-The net movement of molecule from a reigon of lower concentration to a reigon of higher concentration using ATP and carrier protiens

Question 24

what happens in active transport?

Answer 24

-molecule binds to the complementary recptors on a protiens
-ATP binds to the carrier protien
-ATP is hydrolyised in ADP+PI
-the phosphate group stays of the carrier protien- the energy causing the carrier protien to change shape
-molecule is released, phosphate leaves and protien turns back into its orignial shape

Question 25

What is co transport?

Answer 25

-involves atp and faciliated diffusion
-2 molecules

Question 26

What is the example given for co transport?

Answer 26

sodium and glucose molecules in the iluem of the small intestine

Question 27

how does the co transport work in the iluema and epitheal cells

Answer 27

• there is a high conc of sodium in lumen dn low in the epitheal cell (faciliated diffusion)
  -there is a low conc of glucose in lumen and high in epithelial cell (active transport)
  -both of these transport happen in the same carrier protien as the sodium allows the glucose to be transported
  -from the epitheal cell into the caplliaries sodium goes down by active transport and glucose can go into the blood by active transport of faciliated diffusion depending on then concentration