the fluid mosaic model

Question 1

what does the “fluid” part of the name imply?

Answer 1

membranes are not static (able to move)

Question 2

what does the “mosaic” part of the name imply?

Answer 2

membranes consist of a mosaic of different components scattered throughout

Question 3

what does the cell membrane consist of?

Answer 3

phospholipid bilayer
proteins
cholesterol
glycolipids/ glycoproteins

Question 4

what does the phospholipid bilayer consist of?

Answer 4

two layers- hydrophilic and hydrophobic regions

Question 5

what does hydrophilic mean?

Answer 5

polar- the “head” (in contact with water)

Question 6

what does hydrophobic mean?

Answer 6

nonpolar- the “tail” (does not come into contact with water)

Question 7

what does the phospholipid bilayer allow?

Answer 7

small, neutral molecules can pass through spaces in the cell membrane

Question 8

what are the two types of proteins?

Answer 8

peripheral and integral

Question 9

what are peripheral proteins?

Answer 9

an external/ internal surface (hydrophilic)

Question 10

what are integral proteins?

Answer 10

embedded deep in the membrane (mostly hydrophobic)

Question 11

functions of membrane proteins- transportation

Answer 11

move substances across

Question 12

functions of membrane proteins- enzymes

Answer 12

carry out steps in a metabolic pathway

Question 13

functions of membrane proteins- receptor sites

Answer 13

once a chemical messenger binds, initiates a chain reaction of chemical changes in the cell

Question 14

functions of membrane proteins- cell adhesion

Answer 14

holds adjacent cells together

Question 15

functions of membrane proteins- attachment to the cytoskeleton

Answer 15

important in maintaining cell shape and fixes the location of many membrane proteins

Question 16

what is cholesterol?

Answer 16

a 4-fused ring structure embedded within the membrane

a type of lipid

Question 17

what happens to cholesterol at low temperatures?

Answer 17

allows for fluidity by preventing close packing of the phospholipids

Question 18

what happens to cholesterol at high temperatures?

Answer 18

maintains rigidity of phospholipids

Question 19

what is the importance of maintaining “fluidity”?

Answer 19

most membrane components can drift in the plane of the membrane

Question 20

what are glycolipids/ glycoproteins?

Answer 20

carbohydrate chains attached to lipids and proteins

Question 21

where are glycolipids/ glycoproteins found?

Answer 21

external surface only

Question 22

how do cells distinguish from each other?

Answer 22

each cell has its own unique “fingerprint” of carbohydrate chains that distinguish it from other kinds of cells

Question 23

what does “glyco” refer to?

Answer 23

the presence of carbohydrates

Question 24

what are the function of membrane carbohydrates?

Answer 24

cell-to-cell recognition