Plasma Membrane - Chapter 5 - College Biology

Question 1

what are the 3 parts of a phospholipid?

Answer 1

glycerol molecule, two fatty acids, and a phosphate group

Question 2

how do phospholipids orient themselves?

Answer 2

polar heads facing outward towards water molecules, while their hydrophobic tails face inward, forms bilayer

Question 3

fluid mosaic model (4)

Answer 3

mosaic of components (phospholipids, cholesterol, proteins, and carbohydrates) give membrane fluid character

Question 4

proteins (4)

Answer 4

transporters, receptors, enzymes, or in binding and adhesion

Question 5

integral proteins

Answer 5

integrated completely into the bilayer

Question 6

peripheral proteins

Answer 6

occur only on the surfaces

Question 7

carbohydrates

Answer 7

exterior surface plasma membrane, bound to either proteins (forming glycoproteins) or to lipids (forming glycolipids)

Question 8

functions of carbohydrates (2)

Answer 8

cell-cell recognition & attachment

Question 9

recipetor proteins

Answer 9

detect signals and transmit them to the cell’s response machinery

Question 10

membrane fluidity

Answer 10

phospholipid type (sa lipids pack closer than unsa, sfa more rigid)
temp (cold = rigider)
cholesteral (fluidity buffer)

Question 11

transport

Answer 11

allows some molecules to pass through, but not others

Question 12

passive transport

Answer 12

requires no energy moves along gradient example diffuision

Question 13

which only molecules can diffuse without help?

Answer 13

O2, CO2, & lipid hormones, can diffuse
(small, nonpolor)

Question 14

facilitated transport

Answer 14

moves substances down concentration gradients through transmembrane, integral membrane proteins

Question 15

2 types of facilitated transport proteins

Answer 15

channel and carrier proteins

Question 16

channel protiens

Answer 16

pore in the membrane that lets water molecules or small ions through quickly (some open, some aren’t)

Question 17

carrier proteins

Answer 17

bind to that substance, change shape & “carry it” to the other side

Question 18

omosis

Answer 18

diffusion of water across a membrane

Question 19

tonicity

Answer 19

extracellular solution can change the volume of a cell by affecting osmosis

Question 20

osmolarity

Answer 20

describes total solute concentration of a solution (permeable and non-permeable solutes)

Question 21

osmoregulation

Answer 21

organisms that have cell walls prefer hypotonic extracellular solutions

Question 22

active transport

Answer 22

requires energy, moves against concetration gradient

Question 23

primary active

Answer 23

where ATP provides the energy

Question 24

secondary active

Answer 24

where an electrochemical gradient provides the energy

Question 25

electrochemical gradients

Answer 25

determines the direction that ions will flow through an open ion channel

Question 26

hypertonic soulution

Answer 26

water will leave the cell, shirnks

Question 27

isotonic solution

Answer 27

no net water movement, so there is no change in the size of the cell

Question 28

hypotonic solution

Answer 28

water will enter the cell, and the cell will swell

Question 29

selective permeability

Answer 29

membranes can choose to allow or block materials to enter or exit a cell

Question 30

sodium-potassium pump

Answer 30

protein pumps that transport sodium ions out and potassium in

Question 31

bulk trasport

Answer 31

cells need to import or export molecules/particles that are too large to pass through a transport protein, energy required

Question 32

endocytosis and exocytosis

Answer 32

importing vs. exporting by bulk

Question 33

3 types of endocytosis

Answer 33

phagocytosis, pinocytosis, receptor mediated endocytosis

Question 34

phagocytosis

Answer 34

cell membrane surrounds a particle and engulfs it

Question 35

pinocytosis

Answer 35

cell membrane invaginates, surrounds a small volume of fluid, and pinches off

Question 36

receptor-mediated endocytosis

Answer 36

specific substance is targeted by binding to receptors on the external surface of the membrane

Question 37

exocytosis

Answer 37

vesicles containing substances fuse with the plasma membrane