Cell membranes (movement)

Question 1

what is partially permeable membrane

Answer 1

membrane lets some molecules through but not others

Question 2

what are channel and carrier proteins for

Answer 2

allow large molecules and ions to pass through

Question 3

what are receptor proteins for

Answer 3

allow cell to detect chemicals released from other cells

Question 4

whats the name of the model for the arrangement of molecules in the membrane

Answer 4

fluid mosaic model

Question 5

whats the structure of a phospholipid

Answer 5

hydrophilic head point outwards
hydrophobic tail point inwards
- allow lipid soluble molecules to pass but not water soluble
they form a phospholipid bilayer

Question 6

what molecules can pass through phospholipid bilayer

Answer 6

small, non-polar substance
water can diffuse through membrane

Question 7

what is intrinsic protein

Answer 7

proteins integrated throughout the membrane
e.g carrier proteins

Question 8

what is extrinsic protein

Answer 8

proteins on the surface of membrane

Question 9

what are proteins in the membrane for

Answer 9

aid movement
provide mechanical support
act in conjuction with glycolipids as receptors

Question 10

what is cholesterol for

Answer 10

(fits in between phospholipid- bind to hydrophobic tail- cause them to be closer)
gives rigidity and stability
reduce lateral movement of phospholipid
prevent leakage of water and dissolved ions-very hydrophobic

Question 11

what are glycolipids and their function

Answer 11

carbohydrate that is attached to lipid
cell surface receptor
allow cells to adhere to one another to form tissues

Question 12

what are glycoprotein and their function

Answer 12

carbohydrates attached to extrinsic protein
cell surface receptor and neurotransmitter
also allow to form tissues

Question 13

what processes are passive

Answer 13

simple and faciliated diffusion

Question 14

what is simple diffusion and state an example

Answer 14

when molecules directly diffuse through the membrane
e.g oxygen and co2

Question 15

what molecules can pass for simple diffusion

Answer 15

small and non-polar- soluble in lipids

Question 16

what is facilitated diffusion and state examples

Answer 16

diffusion through carrier or channel proteins in cell membrane
e.g glucose, aminno acid, ions

Question 17

what molecules can pass by facilitated diffusion

Answer 17

large and charged molecules

Question 18

whats the conc gradient for diffusion

Answer 18

high to low conc- down a conc gradient

Question 19

whats active transport

Answer 19

movement against the conc gradient using ATP involving carrier protiens and co transporter

Question 20

what does ATP undergo in active transport

Answer 20

hydrolysis- split into ADP and Pi

Question 21

what does co-transporter do

Answer 21

bind 2 molecules at a time
use conc gradient of one molecule to move another against its conc gradient

Question 22

whats the difference between facilitated diffusion and active transport with carrier protein

Answer 22

active transport-
low to high conc
requires ATP

Question 23

what is osmosis

Answer 23

the diffusion of water molecules across a partially permeable membrane from area of highER water potential to an area of lowER water potential

Question 24

what is water potential

Answer 24

the potential of water molecules to diffuse out of or into a solution

Question 25

what the water potential of pure water

Answer 25

0

Question 26

whats the water potential when solutes are added

Answer 26

always negative- the more negative the stronger the conc of solutes

Question 27

whats isotonic

Answer 27

if two solutions have same water potential so no osmosis

Question 28

whats hypotonic

Answer 28

when solutions have a water potential higher than inside of the cell- water moves into cell

Question 29

whats hypertonic

Answer 29

solutions with a lower water potential than inside of cell- so water moves out of cell

Question 30

what factors affect rate of osmosis

Answer 30

water potential gradient
thickness of the exchange surface
surface area of surface

Question 31

what factors affect rate of diffusion

Answer 31

surface area
diffusion distance
conc gradient
temperature

Question 32

explain why phospholipids form a bilateral in plasma membrane

Answer 32

phospholipids have polar phosphate group which are hydrophilic and will face the aq solution
the fatty acid tails are nonpolar and will move away from aq
forms two layers with hydrophobic tails facing inwards and phosphate group outwards interacting with aq environment

Question 33

explain why the model for membrane structure is known as fluid mosaic model

Answer 33

phospholipid molecules can move freely laterally and makes the membrane fluid
cholesterol interacts and binds with fatty acid tails and affects fluidity of the model
the proteins are distributed throughout the membrane unevenly and in mosaic pattern
the agreed structure is based upon experimental and chemical evidence so called a model

Question 34

which organelles are membrane bound

Answer 34

chloroplast
mitochondria
rer
ser
golgi body
lysosome
nucleus

Question 35

what does cholesterol do

Answer 35

bind to fatty acid tails of phospholipids
increase rigidity of the plasma membrane
cause phospholipids to pack tightly