Membrane and passive transport

Question 1

What are phospholipids?

Answer 1

hydrophilic head and hydrophobic tail

Question 2

What is the fluid mosaic model?

Answer 2

-in phospholipid bilayer, proteins embed in it

-switch laterally all the time

-can move around which is important in neurotransmission

Question 3

How much of the membrane is cholesterol? and what does it do?

Answer 3

20% stiffens the membrane using its hydrocarbon rings and decreases water solubility

Question 4

Integeral membrane proteins

Answer 4

Type of membrane protein, Embedded permanently into the membrane, they channel or transport molecules across the membrane

Question 5

what are the functions of the cell membrane

Answer 5

physical barrier, selective permeability, electrochemical gradients, communication, cell recognition

Question 6

What are two jobs of integral proteins in the plasma membrane

Answer 6

peripheral protein to act as channels (transport) or carriers (bind to substance then move it through the membrane`

Question 7

What do peripheral proteins do?

Answer 7

acts as enzymes or motor proteins involved in mechanical functions such as changing cell shape or muscle cell contraction

Question 8

What is glycolax?

Answer 8

glycoprotein and glycolipid covering that surrounds the cell membranes that are highly specific (sugar coating)

-helps recognize other cells

Question 9

cytoskeleton anchors to _____ and can interact with ____

Answer 9

plasma membrane and receptors

Question 10

what are the function of membrane proteins

Answer 10

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and ECM

Question 11

what are tight junctions

Answer 11

fuse together like zipper on Ziploc bag to keep molecules from passing through and restrict membrane movement

e.g. in small intestine to stop microorganisms from entering the blood stream

Question 12

What are desmosomes?

Answer 12

Anchoring junctions that prevent cells from being pulled apart

-bind adjacent like velcro

Question 13

What are gap junctions?

Answer 13

Small tunnels that connect cells (connexons), facilitating the movement of small molecules and ions from cell to cell like in heart cells.

Question 14

What are the two ways substances can move across the cell membrane?

Answer 14

passive and active process (require ATP)

Question 15

what are the three types of passive transport

Answer 15

simple diffusion, osmosis, facilitated diffusion

Question 16

What is diffusion?

Answer 16

The movement of particles from an area of high concentration to an area of low concentration.

Question 17

what is another name for movement from high to low concentrations?

Answer 17

concentration gradient

Question 18

what are the two criteria for how easily a substance can cross the cell membrane

Answer 18

1) it size and 2) lipid solubility

Question 19

What is facilitated diffusion?

Answer 19

Movement of specific molecules across cell membranes through protein channels

Question 20

What is carrier mediated transport?

Answer 20

when a solute binds to a carrier in the plasma membrane, which then changes shape and releases the solute to the other side

-unicellular

Question 21

what is channel mediated diffusion?

Answer 21

Crossing through membrane protein that forms selective channel

Question 22

What is osmosis?

Answer 22

diffusion of water across a selectively permeable membrane

Question 23

what is Tonocity?

Answer 23

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

Question 24

What are isotonic solutions?

Answer 24

-If two solutions have the same water potential they’re said to be isotonic.

Question 25

What is a hypertonic solution?

Answer 25

The solution has a higher solute concentration than the cell so water moves out of the cell; shrinks

Question 26

what is a hypotonic solution?

Answer 26

the solution has a lower solute concentration than the cell so water moves into the cell causing plant cells to swell and animal cells to swell and burst

Question 27

what is the difference between osmolarity and tonicity?

Answer 27

osmolarity is based on total solute concentration. tonacity is based on how the solution affect cell volume based on solute concentration and its permability

Question 28

what are the two important characteristics of passive transport?

Answer 28

specificity and solubility