Membrane Transport

Question 1

<p><em>Components of the</em></p>

<p><strong>Cell Membrane</strong></p>

Answer 1

<p>Phospholipid bilayer <br></br>Proteins <br></br>Cholesterol (in animal cells) <br></br>Glycoproteins and Glycolipids</p>

Question 2

<p><em>Structure of a</em></p>

<p><strong>Phosphospholipid</strong></p>

Answer 2

<p>Phosphate group <br></br>Two hydrocarbon chains</p>

Question 3

<p><em>Properties of</em></p>

<p><strong>Phospholipids</strong></p>

Answer 3

<p>Phosphate heads are hydrophilic <br></br>Lipid tails are hydrophobic and can be saturated or unsaturated</p>

Question 4

<p><em>Structure of the</em></p>

<p><strong>Phospholipid bilayer</strong></p>

Answer 4

<p>Phosphates face outward toward extracellular environment and cytoplasm; <br></br>Lipids are sandwiched between phosphates<br></br>More unsaturated fatty acids increase the fluidity of the bilayer</p>

Question 5

<p><em>Types of</em></p>

<p><strong>Membrane Proteins</strong></p>

Answer 5

<p>Integral and peripheral</p>

Question 6

<p><em>Describe</em></p>

<p><strong>Integral Protein</strong></p>

Answer 6

<p>A protein that goes completely through the phospholipid bilayer; must have hydrophobic portion</p>

Question 7

<p><em>Describe</em></p>

<p><strong>Peripheral Protein</strong></p>

Answer 7

<p>A protein affixed to either the extracellular side or cytoplasmic side of the membrane</p>

Question 8

<p><em>Function of</em></p>

<p><strong>Phospholipid bilayer</strong></p>

Answer 8

<p>Fluid-like structure in which proteins and other molecules are embedded; permeable to small and non-polar membranes</p>

Question 9

<p><em>Function of</em></p>

<p><strong>Membrane Proteins</strong></p>

Answer 9

<p>Transport of particles through membrane <br></br>Cell recognition <br></br>Anchoring/attachment <br></br>Enzymes</p>

Question 10

<p><em>Function of</em></p>

<p><strong>Cholesterol</strong></p>

Answer 10

<p>Keeps animal cells fluid over a wider range of temperatures than without them present</p>

Question 11

<p><em>Function of</em></p>

<p><strong>Glycoproteins and Glycolipids</strong></p>

Answer 11

<p>Cell recognition</p>

Question 12

<p><em>Describe</em></p>

<p><strong>Diffusion</strong></p>

Answer 12

<p>Movement of particles from an area of higher concentration to lower concentration <br></br>Does not require the input of cellular energy <br></br>Continues until dynamic equilibrium is reached</p>

Question 13

<p><em>Describe</em></p>

<p><strong>Diffusion through membranes</strong></p>

Answer 13

<p>Small, non-polar molecules move easily through phospholipid bilayer <br></br>No cellular energy is required <br></br>Particles move from area of high to low concentration</p>

Question 14

<p><em>Describe</em></p>

<p><strong>Facilitated diffusion</strong></p>

Answer 14

<p>Large and/or polar molecules move through specific membrane proteins <br></br>No cellular energy is required <br></br>Particles move from area of high to low concentration </p>

Question 15

<p><em>Explain</em></p>

<p><strong>Specificity of transport proteins</strong></p>

Answer 15

<p>Each transport protein is specific to only one type of particle <br></br>The presence/absence of certain transport proteins determines what the membrane is(n’t) permeable to</p>

Question 16

<p><em>Two factors involved in</em></p>

<p><strong>Concentration Gradient</strong></p>

Answer 16

<p>Diffusion distance (how far particles must travel) and Concentration difference between two areas</p>

Question 17

<p><em></em></p>

<p><strong>Factors that increase the rate of diffusion</strong></p>

Answer 17

<p>Increased temperature <br></br>Increased concentration difference<br></br>Smaller diffusion distance <br></br>Smaller particles</p>

Question 18

<p><em>Two types of </em></p>

<p><strong>Transport proteins</strong></p>

Answer 18

<p>Channels and carrier proteins</p>

Question 19

<p><em>Define</em></p>

<p><strong>Osmosis</strong></p>

Answer 19

<p>The diffusion of water through aquaporins from areas of higher water potential to lower water potential</p>

Question 20

<p><em></em></p>

<p><strong>Aquaporin</strong></p>

Answer 20

<p>A protein channel specific to water</p>

Question 21

<p><em>Define</em></p>

<p><strong>Osmolarity</strong></p>

Answer 21

<p>Solute concentration of a solution</p>

Question 22

<p><em>Define</em></p>

<p><strong>Hypotonic</strong></p>

Answer 22

<p>A solution with a relatively lower solute concentration than solution on the opposite side of a membrane</p>

Question 23

<p><em>Define</em></p>

<p><strong>Hypertonic</strong></p>

Answer 23

<p>A solution with a relatively higher solute concentration than solution on the opposite side of a membrane</p>

Question 24

<p><em>Define</em></p>

<p><strong>Isotonic</strong></p>

Answer 24

<p>Two solutions on either side of a membrane that have reached dynamic equilibrium</p>

Question 25

Plants in a hypotonic solution are

Answer 25

Turgid

Question 26

Plants in an isotonic solution are

Answer 26

A little wilty

Question 27

Plants in a hypertonic solution are

Answer 27

Very wilty; may plasmolyze

Question 28

Animal cells in a hypotonic solution

Answer 28

Swell; may lyse

Question 29

Animal cells in an isotonic solution

Answer 29

Happy

Question 30

Animal cells in a hypertonic solution

Answer 30

Shrivel

Question 31

Define

Water potential

Answer 31

Water’s ability to move/displace other substances

Question 32

Which way does water move?

Answer 32

From higher water potential to lower water potential

Question 33

What affects if osmosis will occur?

Answer 33

Osmosis is ONLY considered if the membranes are not permeable to other solutes

Question 34

Define

Solute Potential

Answer 34

The decrease of water’s potential due to the presence of solutes in the solution

Question 35

Define

Pressure Potential

Answer 35

The increase of water’s potential due to the pressure exerted on the solution

Question 36

Ψ_S=-iCRT
Explain each part of this formula

Answer 36

Ψ_S is solute potential
I is the ionization constant
C is the molar concentration
R is a constant
T is temperature (in Kelvin)