membranes

Question 1

what permeability is the plasma membrane

Answer 1

semi permeable

Question 2

what does amphipathic mean

Answer 2

both hydrophobic and hydrophilic regions

Question 3

what two types of glycoproteins are in the membrane

Answer 3

integral and peripheral

Question 4

what is the fluid mosaic model

Answer 4

proteins bobbing in a bilayer of phospholipids

Question 5

what are lipid rafts

Answer 5

groups of specific proteins and lipids that are organized in specialized patches

Question 6

how is the membrane held together

Answer 6

by hydrophobic interactions

Question 7

how does a membrane increase fluidity in cold temperatures

Answer 7

increase the number of unsaturated fats in the membrane

Question 8

what types of organisms need to adjust the saturated/unsaturated fats at colder temperatures

Answer 8

cold blooded

Question 9

can the lipids and proteins move in the membrane

Answer 9

yes, both move laterally, proteins slower than lipids

Question 10

where are carbohydrates located in the membrane

Answer 10

on the non cytosolic side (extracellular)

Question 11

what are integral proteins

Answer 11

penetrate interior of the membrane, embedded/transmembrane

Question 12

what are peripheral proteins

Answer 12

proteins that are not embedded in bilayer

Question 13

what are the 6 protein functions

Answer 13

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and ecm

Question 14

what does sidedness of membranes mean

Answer 14

everything has directional orientation

Question 15

permeability of hydrophobic molecules

Answer 15

dissolve easily, able to cross without help (CO2, O2)

Question 16

Small Polar permeability

Answer 16

able to dissolve but pass slowly (glucose, water, sugars)

Question 17

ion permeability

Answer 17

do not diffuse, need transport helpers

Question 18

macromolecules

Answer 18

do not diffuse, need exo/endocytosis

Question 19

what are transport proteins

Answer 19

allow ions/molecules to pass through membrane

Question 20

what are the two types of transport proteins

Answer 20

channel and carriers

Question 21

what type of transport is channel proteins

Answer 21

passive, like aquaporins

Question 22

what type of transport is carriers

Answer 22

passive and active —> depending on the substance it moves

Question 23

what is diffusion, is it passive or active?

Answer 23

movement of particles down concentration gradient, passive and spontaneous

Question 24

what is osmosis

Answer 24

the diffusion of free water across a a selectively permeable membrane

Question 25

what is tonicity

Answer 25

ability of solution to modify volume of cell by changing the water content

Question 26

what are the three types of tonicity

Answer 26

isotonic, hypertonic, hypotonic

Question 27

what does isotonic mean

Answer 27

equal solute concentrations on either side, no net movement

Question 28

what does hypertonic mean

Answer 28

high solute concentration outside of cell, water movement out of cell

Question 29

what does hypotonic mean

Answer 29

high solute concentration in the cell, water movement in

Question 30

what is an animal cell like in each solution? what is normal

Answer 30

normal = isotonic shrivelled = hypertonic lysed = hypotonic

Question 31

what is a plant cell like in each solution? what is normal

Answer 31

flaccid = isotonic plasmolyzed = hypertonic (membrane pulls away from cell wall) turgid/normal = hypotonic

Question 32

what is facilitated diffusion

Answer 32

passive diffusion with help of transport proteins

Question 33

what is active transport

Answer 33

movement against concentration gradient (upwards), requires energy

Question 34

what is an electrogenic pump

Answer 34

form of active transport, generates voltage across a membrane

Question 35

what is a common electrogenic pump in animals

Answer 35

sodium-potassium pump, pumps K+ inside and Na+ outside

Question 36

what is a common electrogenic pump in plants

Answer 36

proton pump, transports H+ out of the cell

Question 37

what is cotransport

Answer 37

transporter protein couples downhill diffusion of one solute to the uphill diffusion of another against its C.G

Question 38

what is an example of cotransport

Answer 38

diffusion of h+, sucrose is able to be transported

Question 39

why is active transport beneficial

Answer 39

allows cells to maintain solute concentrations that differ from concentration of environment

Question 40

what is exocytosis

Answer 40

the secretion of large molecules ---> fusion of vesicles with the plasma membrane, like insulin neurotransmitter

Question 41

what is endocytosis

Answer 41

uptake of large molecules ---> form new vesicles from plasma membrane

Question 42

what are the three types of endocytosis

Answer 42

phagocytosis, pinocytosis, receptor-mediated

Question 43

what is pinocystosis

Answer 43

nonspecific uptake of smaller molecules, AKA cell drinking

Question 44

what is receptor mediated endocytosis

Answer 44

targeted pinocytosis ex) LDLs uptake of cholesterol