ch7

Question 1

what does the cell membrane consist of?

Answer 1

lipid bilayer

Question 2

cell membrane

Answer 2

membrane is a continuous boundary layer that selectively controls the flow of substances across it

Question 3

functions of plasma membrane

Answer 3

• selectively isolate the cell’s contents from the external environment
• regulate the exchange of essential substances
• communicate with other cell

Question 4

three major membrane proteins

Answer 4

• transport protein: channel and carrier proteins
• receptor protein
• recognition protein

Question 5

factors affecting diffusion rate

Answer 5

• steepness of concentration gradient: steeper gradient, faster diffusion
• molecular size: smaller molecules, faster difusion
• temperature: higher temperature, faster diffusion
• electrical or pressure gradients

Question 6

three types of passive transports

Answer 6

simple diffusion, facilitated diffusion, osmosis

Question 7

osmosis

Answer 7

the diffusion of water across membranes

Question 8

isotonic solution

Answer 8

having some strength

Question 9

hypertonic solution

Answer 9

having greater

Question 10

hypotonic solution

Answer 10

having lesser

Question 11

dissolved substances do what?

Answer 11

reduce the concentration of water molecules

Question 12

active transport

Answer 12

uses energy to move molecules against their concentration gradients

Question 13

two active sites

Answer 13

one binds a particular molecule or ion such as calcium ion; second site binds ATP

Question 14

endocytosis

Answer 14

engulf particles or fluids

Question 15

tonicity

Answer 15

the ability of a surrounding solution to cause a cell to gain or lose water

Question 16

three types of endocystosis

Answer 16

1. pinocytosis - moves liquid into the cell
2. receptor - mediated endocytosis moves specific molecules into the cell
3. phagocystosis - moves large particles into the cell

Question 17

exocytosis

Answer 17

moves material out of the cell vs. endocytosis

Question 18

transport across membranes

Answer 18

Question 19

diffusion

Answer 19

the net movement of like molecules or ions down a concentration gradient

Question 20

fluid

Answer 20

change shapes and move freely; liquid and gases

Question 21

gradient

Answer 21

physical differences in temp. pressure concentration, and electrical particles

Question 22

concentration

Answer 22

number of molecules in a given volume

Question 23

hydrostatic pressure

Answer 23

pressure exerted by fluid on the walls that contain it (the greater the solute concentration of the fluid, the greater the hydrostatic pressure)

Question 24

osmotic pressure

Answer 24

amount of pressure necessary to prevent further increase of a solution’s volume

Question 25

amphipathic

Answer 25

containing hydrophobic (water-fearing) and hydrophilic (water loving) regions

Question 26

fluid mosaic model

Answer 26

both proteins and lipids drifting constantly moving laterally and horizontally

Question 27

three factors that affect membrane movement

Answer 27

1. temperature factor 2. number of saturated or unsaturated fatty acids 3. temperature along with lipid molecule (cholesterol)

Question 28

six major functions of plasma membrane (membrane proteins)

Answer 28

1. transport protein or carry protein 2. enzymatic activity (all enzymes are proteins) 3. signal transduction 4. cell-cell recognition (identification tag) 5. intercellular joining 6. attachment to the cytoskeleton and extracellular matrix (ECM)

Question 29

Isotonic

Answer 29

plant cell: normal plant cell: flaccid - wilt(limp)

Question 30

hypotonic

Answer 30

animal cell: lysis (lysed) - exploded cell plant cell: turgid - swallowed (firm)

Question 31

hypertonic

Answer 31

animal cell: shriveled plant cell: plasmolyzed

Question 32

plasmolysis

Answer 32

the only way a plant can die, because it loses water

Question 33

sodium-potassium pump protein

Answer 33

the transport of k^+ into the cell and Na^+ out of the cell

Question 34

membrane potential

Answer 34

the voltage across a membrane

Question 35

electrochemical gradient

Answer 35

drive the diffusion of ions across a membrane

Question 36

electrogenic pump

Answer 36

a transport protein that generates voltage across a membrane, storing energy that can be used for cellular work