Lecture 16

Question 1

Membrane structure is held together by:

Answer 1

Hydrogen bonds

Question 2

Lipids rarely flip flop between membrane leaflets therefore the lipid composition of the leaflets can be asymmetric. T/F?

Answer 2

True

Question 3

How does lipid tail length affect the fluidity of the membrane?

Answer 3

The longer the tail, the less fluid the membrane

Question 4

How does the number of double bonds affect the fluidity of the membrane?

Answer 4

More double bonds increases fluidity

Question 5

How does the amount of cholesterol affect membrane fluidity?

Answer 5

More cholesterol decreases fluidity

Question 6

Integral proteins are:

Answer 6

Proteins that extend into or completely across cell membrane (transmembrane)

Question 7

Peripheral proteins:

Answer 7

Attached to either the inner or outer surface of cell membrane and are easily removed from it.

Question 8

Integral proteins polarity:

Answer 8

amphipathic

Question 9

Functions of membrane proteins (x6)

Answer 9

Receptor, cell identity markers, linkers, enzymes, ion channels, transporters

Question 10

Channel proteins:

Answer 10

Allow specific substances to move through water filled pore.

Question 11

Transport proteins:

Answer 11

Transport specific substances across membrane by changing shpa.e Amino acids enter body cells via transporters.

Question 12

Selective permeability of membrane: (x4)

Answer 12

Permeable to nonpolar, uncharged molecules. Permeable to lipid soluble molecules. Permeable to small uncharged polar molecules.

Question 13

Impermeability of membrane:

Answer 13

-Impermeable to large uncharged polar molecules.

Impermeable to ions.

Question 14

The greater the difference in concentration between the 2 sides of the membrane, the ______ the rate of diffusion.

Answer 14

faster

Question 15

The higher the temperature, the _____ the rate of diffusion

Answer 15

faster

Question 16

An increase in surface area, _______ the rate of diffusion

Answer 16

increases

Question 17

Increasing diffusion distance, ___ rate of diffusion

Answer 17

slows

Question 18

What is 1 outcome of a cell increasing the membrane area available for diffusion?

Answer 18

increases diffusion

Question 19

How does membrane thickness affect diffusion

Answer 19

Slows

Question 20

Diffusion is very fast over ___ distances

Answer 20

small

Question 21

Movement of ions will be influenced by the _____ _____

Answer 21

electrical gradient

Question 22

What enables a difference in concentration gradient across the membrane to be established?

Answer 22

The selective permeability. The difference in charged ions between the inside and outside of membrane establishing an electrical gradient.

Question 23

Osmosis:

Answer 23

diffusion of water across membranes.

Question 24

Osmosis only occurs when:

Answer 24

Only occurs if membrane is permeable to water but not to certain solutes.

Question 25

Define Pw, Pd, and Pf.

Answer 25

Pw = membrane permeability to water. Pd - permeability of lipid bilayer. Pf- permeability of water channel/aquaporins.

Question 26

Pw eq

Answer 26

Pw = Pd + Pf. Pf > Pd

Question 27

Water channels are also called

Answer 27

aquaporins

Question 28

Properties of Pd

Answer 28

Small, mercury insensitive, temp dependent

Question 29

Properties of Pf

Answer 29

Large, mercury sensitive, temperature independent

Question 30

Osmotic pressure is:

Answer 30

the pressure applied by a solution to prevent the inward flow of water across a semi-permeable membrane

Question 31

If the solution has the same osmolarity it is:

Answer 31

isosmotic

Question 32

If the solution has a lower osmolarity it is

Answer 32

hyposmotic

Question 33

If the solution has a higher osmolarity it is:

Answer 33

hyperosmotic

Question 34

What kind of solution causes cell swelling and lysis?

Answer 34

Hypotonic

Question 35

What kind of solution causes cell shrinkage (crenation)?

Answer 35

Hypertonic