Chapter 6

Question 1

what do cell membranes define?

Answer 1

the boundary of the cell

Question 2

why are cell membranes considered fluid?

Answer 2

because the structure is not fixed and lets molecules in and out

Question 3

why are cell membranes considered mosaic?

Answer 3

because they have different protein molecules embedded

Question 4

cell membranes are made up primarily of what?

Answer 4

a bilayer of phospholipids

Question 5

cell membranes are made up of mostly a bilayer of phospholipids with what?

Answer 5

embedded proteins, carbohydrates, glycolipids, glycoproteins, and cholesterol

Question 6

is there cholesterol in the cell membrane of plants?

Answer 6

no, just animals

Question 7

what are the two types of transport?

Answer 7

passive and active transport

Question 8

does passive transport require atp for molecule movement?

Answer 8

no

Question 9

does active transport require atp for molecule movement?

Answer 9

yes

Question 10

in passive transport, molecules move…

Answer 10

from higher concentration to lower concentration

Question 11

in active transport, molecules move…

Answer 11

against the gradient

Question 12

the most direct forms of naturally occuring transport?

Answer 12

passive transport

Question 13

membranes have hydropholic and hydrophobic regions, what does this do?

Answer 13

it helps the transport of some materials and hinders that of others

Question 14

what kind of material can slip easily through the hydrophobic lipid core of the cell membrane?

Answer 14

lipid-soluble material

Question 15

what are some examples of passive transport?

Answer 15

diffusion, facilitated diffusion, and osmosis

Question 16

what is diffusion?

Answer 16

a material moves from an area with a high concentration to an area with low concentration until concentration is equal across the area

Question 17

what is facilitated transport?

Answer 17

materials diffuse across the plasma membrane with the help of membrane proteins

Question 18

does facilitated transport require energy?

Answer 18

no

Question 19

does facilitated transport require concentration?

Answer 19

yes

Question 20

what are transport proteins?

Answer 20

integral proteins involved in facilitated transport

Question 21

what is osmosis?

Answer 21

a special type of diffusion of water from a higher concentration to a lower one through a semipermeable membrane

Question 22

what does tonicity mean?

Answer 22

how an extracellular solution can affect the volume of the cell by affecting osmosis

Question 23

what does hypotonic mean?

Answer 23

this means that the extracellular solution has a lower concentration of solutes

Question 24

what does hypertonic mean?

Answer 24

this means that the extracellular solution has a higher concentration of solutes

Question 25

what does isotonic mean?

Answer 25

this means that the extracellular solution has the same concentration as the cell's cytoplasm

Question 26

what form of energy does active transport typically use?

Answer 26

adenosine triphosphate, atp

Question 27

ions move in and out of the cell membrane and proteins that do not move across the cell membrane are negatively charged. What happens as a result of this?

Answer 27

an electrical gradient, a difference of charge across the plasma membrane

Question 28

what is the electrochemical gradient?

Answer 28

the combined gradient of concentration and electrical charge that affects an ion

Question 29

what are some types of endocytosis?

Answer 29

pinocytosis, phagocytosis, and receptor-mediated endocytosis

Question 30

what is endocytosis?

Answer 30

a type of active transport that moves large particles into the cell

Question 31

what is the common characteristic that all types of endocytosis share?

Answer 31

the plasma membrane forms a pocket for the target particle then envelopes it in it.

Question 32

what is phagocytosis?

Answer 32

the process by which large particles are taken in by the cell

Question 33

what is pinocytosis?

Answer 33

the process by which cells take in molecules, including water, from extracellular fluid

Question 34

what is another name for pinocytosis?

Answer 34

cell drinking

Question 35

what is receptor-mediated endocytosis?

Answer 35

a type of endocytosis that employs receptor proteins in the plasma membrane that have a specific binding affinity for certain substances

Question 36

what is exocytosis?

Answer 36

the opposite of endocytosis, expels material from the cell into the extracellular fluid