cell membrane and transport

Question 1

what’s another term for cell membrane

Answer 1

plasma membrane

Question 2

what molecules make up the bilayer

Answer 2

phospholipids, proteins, cholesterol

Question 3

which parts of the bilayer are polar?

Answer 3

heads of the phospholipids

Question 4

which parts of the bilayer are hydrophobic

Answer 4

tails

Question 5

which parts of the bilayer are nonpolar

Answer 5

tails

Question 6

which parts of the bilayer are hydrophilic

Answer 6

heads

Question 7

how do the phospholipids aid in structure

Answer 7

the hydrophilic heads face towards the water while the hydrophobic tails cluster inward, creating a stable barrier

Question 8

cholesterol job in the bilayer

Answer 8

influence membrane fluidity

Question 9

membrane proteins job in bilayer

Answer 9

embedded in the structure- enabling various cellular processes

Question 10

types of membrane proteins

Answer 10

integral (transmembrane), peripheral (surface)

Question 11

peripheral protein function

Answer 11

signal transduction, cell recognition,attachment to cytoskeleton

Question 12

integral protein function

Answer 12

some are receptors for cell communication, some receptors have have carbohydrates attached, some are transport proteins that move material in/out of the cell

Question 13

cholesterol location in cell membrane

Answer 13

interior of the bilayer

Question 14

cholesterol function in cell membrane

Answer 14

Strengthen and Support: reduces membrane fluidity by reducing phospholipid movement, hinders solidification at low temperatures, interferes with saturated hydrocarbons, restrains movement at high temps

Question 15

How does this cholesterol chemical properties allow for its function

Answer 15

Cholesterol is hydrophobic, which allows it to interact with the hydrophobic tails of phospholipids, helping stabilize the membrane fluidity

Question 16

carbohydrates location in cell membrane

Answer 16

outer surface of cell membrane

Question 17

carbohydrates function in cell membrane

Answer 17

help cells distinguish one cell from another

Question 18

main functions of cell membrane

Answer 18

Forms a boundary between inside and outside of cell, controls transport of materials going in and out of cell, involved in communication/recognition and binding between cells, involved in cell signaling and sending messages

Question 19

How does the phospholipid bilayer help achieve the function of selective permeability?

Answer 19

The hydrophobic tails prevent most molecules from simply diffusing across, only allowing non-polar molecules to easily pass through. Larger molecules only pass through with the assistance of membrane proteins (channels, carriers, pumps)

Question 20

definition of selective permeability

Answer 20

Enables a cell to maintain homeostasis(maintaining inside conditions despite the outside environment), allows molecules to cross several ways

Question 21

What is the criteria for substances to be able to diffuse across membrane?

Answer 21

Size, solubility, charge

Question 22

Which types of molecules can pass with ease?

Answer 22

Small, hydrophobic(nonpolar), neutral molecules

Question 23

What part (and its properties) of the membrane makes it selectively permeable?

Answer 23

Two phospholipid layers, heads on the outside (philic,polar), tails on inside (phobic, nonpolar)

Question 24

what is simple diffusion

Answer 24

passage of material through the membrane with concentration gradient, without the help of a transport protein or energy

Question 25

what drives simple diffusion

Answer 25

concentration gradient

Question 26

identify substances that can diffuse freely compared to substances that use a protein

Answer 26

gases, small uncharged molecules, nonpolar, small lipids, oxygen, carbon dioxide

Question 27

describe facilitated diffusion

Answer 27

diffusion across membrane through transport proteins

Question 28

what drives/is responsible for facilitated diffusion

Answer 28

concentration gradient

Question 29

how faciliated is this different than simple diffusion

Answer 29

molecules transport through the transport proteins

Question 30

Give an example of substances that would need facilitated diffusion to move across the membrane.

Answer 30

Charged/polar/large molecules, glucose, chloride ions

Question 31

describe osmosis

Answer 31

facilitated diffusion of water molecules across a semi permeable membrane

Question 32

what drives osmosis

Answer 32

Concentration gradient (high to low) with aquaporin

Question 33

describe isotonic

Answer 33

same concentration of solutes and solvents in/outside of cell, = amount of water exiting/entering cell, no net movement , cell remains same size

Question 34

describe hypertonic

Answer 34

solution it is sitting in has more solutes, net movement of water will move out of cell, cell will decrease in size and mass

Question 35

describe hypotonic

Answer 35

if a cell is sitting in a hypotonic solution it is sitting in a solution w/ less solutes (more water), than inside cell, hypo=more water

Question 36

how is active transport different from passive transport

Answer 36

Requires energy input from the cell, passive does not

Question 37

Which way are molecules/substances moving in terms of concentration for active transport

Answer 37

Low to high concentration

Question 38

What powers active transport

Answer 38

energy (ATP)

Question 39

what is endocytosis

Answer 39

cell membrane takes in macromolecules by folding in on itself and forming new vesicles derived from cell membrane

Question 40

what is exocytosis

Answer 40

internal vesicles containing macromolecules move to the cell surface and fuse with the cell membrane. The macromolecules are released into the extracellular space.

Question 41

what powers Endo and exocytosis

Answer 41

energy (ATP)