unit 2 quiz 2 (over 2.3, 2.4, and 2.5)

Question 1

four parts of phospholipids

Answer 1

1. phosphate group
2. glycerol
3. polar hydrophilic head
4. nonpolar hydrophobic tails

Question 2

saturated fatty acid chain

Answer 2

no double bonds between carbons in carbon chain

Question 3

unsaturated fatty acid chain

Answer 3

one or more double bonds

Question 4

plasma membrane

Answer 4

separates internal and external cell environments

comprised of phospholipids (amphipathic-having both hydrophilic parts and hydrophobic parts)

Question 5

selective permeability

Answer 5

the ability of membranes to regulate the substances that enter/exit

Question 6

fluid mosaic model

Answer 6

model to describe the structure of cell membranes

mosaic: comprised of many macromolecules

fluid: membrane is held together by weak hydrophobic interactions and can therefore move and shift
–> temp affects fluidity
–> unsaturated hydrocarbon tails help maintain fluidity at low temps
—-> kinked tails prevent tight packing of phospholipids

Question 7

cholesterol

Answer 7

helps maintain fluidity

high temps: reduces movement
low temps: reduces tight packaging of phospholipids

Question 8

membrane proteins

Answer 8

integral proteins
peripheral proteins

Question 9

integral proteins

Answer 9

proteins that are embedded into the lipid bilayer
–> transmembrane proteins
–> amphipathic

Question 10

peripheral proteins

Answer 10

proteins that aren’t embedded into lipid bilayer
–> loosely bonded to surface

Question 11

membrane carbs

Answer 11

glycolipids
glycoproteins

Question 12

glycolipids

Answer 12

carbs bonded to lipids

Question 13

glycoproteins

Answer 13

carbs bonded to proteins
–> most abundant

Question 14

cell wall

Answer 14

covers plants plasma membranes
–> provides shape/structure, protection, and regulation of H2O intake

composed of cellulose
–> thicker than plasma mem.
–> contain plasmodesmata
—-> hole-like structures filled with cytosol that connect adjacent cells