Ch.5 Structure and Function of Plasma Membranes

Question 1

Fluid Mosaic Model

Answer 1

describes the plasma membrane structure as mosaic of components

Question 2

Liposomes

Answer 2

bilayer sphere

Question 3

Misceles

Answer 3

single lipid sphere

Question 4

Integral Proteins

Answer 4

integrate completely into membrane structure

Question 5

Peripheral Proteins

Answer 5

not completely integrated in membrane interior or exterior

Question 6

Selectively Permeable

Answer 6

allowing some substances to pass through but not others

Question 7

Passive Transport

Answer 7

naturally occuring, does not require extra energy from cell

Question 8

Diffusion

Answer 8

movement across a selectively permeable membrane and down the concentration gradient (goal is to equalize solution concentration)
each will have own gradient

Question 9

What affects the Concentration Gradient

Answer 9

steepness of concentration gradient
size of molecule
temperature
solvent density
solubility
surface area and thickness and plasma membrane
distance travelled

Question 10

concentration gradient

Answer 10

difference in concentration between two adjacent regions

molecules move from high concentration to low

Question 11

Facilitated transport/ facilitated diffusion

Answer 11

materials diffuse across membrane with the help of membrane proteins

Question 12

transport proteins

Answer 12

integral proteins involved function as either channels or carriers for material

Question 13

channel proteins

Answer 13

phillic channels allow polar molecules to cross

can either be constantly open or gated

Question 14

carrier proteins

Answer 14

move bound molecule to cell out to in

depending on gradient may move in opposite direction

Question 15

osmosis

Answer 15

movement of water down its concentration gradient
inversely proportional to solutes concentration
moves from lower solute concentration to region of higher solute concentration

Question 16

Tonicity

Answer 16

describes how an extracellular solution can change a cells volume by affecting osmosis

Question 17

Osmolarity

Answer 17

solutions total solute concentration

Question 18

low osmolarity

Answer 18

greater number of water molecules relative to solute particles

Question 19

high osmolarity

Answer 19

fewer number of water molecules relative to solute particles

Question 20

Hypotonic

Answer 20

extracellular fluid= low osmolarity

water will enter cell

Question 21

Hypertonic

Answer 21

cytoplasm = low osmolarity
extracellular fluid
water will leave the cell

Question 22

Isotonic

Answer 22

same osmolarity all around

Question 23

crenate

Answer 23

cell shrinks

Question 24

lyse

Answer 24

cell burst

Question 25

plasmolysis

Answer 25

cell membrane detaches from cell wall and constricts the cytoplasm cell wall prevent lysing by acting like a barrier plants cytoplasm always slightly hypertonic to cell environment so water enters the cell

Question 26

How do substances cross the membrane

Answer 26

passive transport active transport endocytosis and exocytosis

Question 27

Active Transport

Answer 27

mechanisms require the cells energy ATP | moves solute against concentration gradient usually thru a pore, channel, gate

Question 28

Electrochemical Gradient

Answer 28

combined gradient of concentration and electrical charge that affects an ion cells mostly negative inside

Question 29

Active Transport Mechanisms/ pumps

Answer 29

work against electrochemical gradient | depend on a cell's metabolism for energy so sensitive to to metabolic poisons that interfere with ATP supply

Question 30

Primary Active Transport

Answer 30

moves ions across a membrane which is dependant on ATP

Question 31

Secondary Active Transport

Answer 31

does not directly require ATP , movement of material due to the electrochemical gradient established by primary active transport

Question 32

Transporters

Answer 32

carrier proteins or pumps used to fascilitate movement

Question 33

Uniporter

Answer 33

carries one specific ion of molecule

Question 34

Symporter

Answer 34

carries two different ions or molecules both in same direction

Question 35

Antiporter

Answer 35

carries two different ions or molecules in different directions

Question 36

Electrogenic Pump

Answer 36

pump creates a charge imbalance, creating electrical imbalance across the membrane and contributing to the membrane potential

Question 37

Exocytosis

Answer 37

fusion of vesicle with the cell membrane, releasing contents into surroundings (exit cell)

Question 38

Endocytosis

Answer 38

formation of a vesicle from cell membrane, enclosing materials near the cell surface and bringing them into the cell (enter cell)

Question 39

Receptor Mediated Endocytosis

Answer 39

specific molecules bind to surface receptors, which are then enclosed in an endocytic vesicle

Question 40

Phagocytosis

Answer 40

larger target particles such as microbes or cellular debris are engulfed by pseudopods which merge as a vesicle which fuses with a lysosome in the cell (cell eating LARGE)

Question 41

Pinocytosis

Answer 41

a less selective endocytic pathway that brings small volume fluid into the cell (cell drinking SMALL)

Question 42

Clathrin

Answer 42

coats plasma membrane to prepare for phagocytosis and stabalizes this membrane section

Question 43

Potocytosis

Answer 43

variation of pinocytosis and uses coating protein caveolin similarly to clathrin

Question 44

plasma membrane component can either be found on its surface or embedded in its structure

Answer 44

protein

Question 45

what keeps bilayer fluid

Answer 45

cholesterol

Question 46

water moves via____ from an area of high water concentration to one with a lower water concentration

Answer 46

osmosis

Question 47

what happens with freshwater organisms

Answer 47

take in too much water

Question 48

when would passive transport not use a transport protein for cell entry

Answer 48

oxygen moving into a cell after oxygen deprivaton

Question 49

what happens to the membrane of a vesicle after exocytosis

Answer 49

becomes part of plasma membrane

Question 50

what brings a whole cell into a cell

Answer 50

phagocytosis

Question 51

`for a virus to use receptor mediated endocytosis

Answer 51

because it only targets a specific substance

Question 52

what organelle relies on exocytosis to complete its function

Answer 52

golgi aparatus