Membrane Function Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what are the basic membrane functions?

A
  • maintain internal cell environment at a steady state regardless of changes in the external environment
  • acts a selective barrier regulating the movement of substances into and out of the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 3 main types of transport?

A

passive
active
bulk membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the types of passive transport

A

simple duffusion
facilitated diffusion (channel, carrier)
osmosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the type of active transport

A

pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

types of bulk membrane transport

A
  • endosytosis
  • exocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

diffusion

A

substance spreads out since molecules are constantly in motion and bumping into each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

passive transport definition

A

does not require energy and molecules move from high to low concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

simple diffusion/transfer

A

movement accross a semi-permeable membrane, down a concetration gradient, no energy required, continues until equilibrium is achieved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what type of molecules go through simple diffusion?

A

O2 and CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

facilitated transport

A

across a semi permeable membrane passive transport, continues until equilibrium is achieve, moves through a channel or carrier proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what types of particles go through channel proteins

A

small dissolved charged molecules like ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

aquaporins

A

a specific type of channel protein that facilitate the movement of water molecules across a membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

carrier proteins

A

acts like turnstile/revolving door, underoges conformational change to allow molecules through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

types of particles through carrier proteins

A

moves a variety of substnaces from charged particles to large uncharged molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

uniport

A

movement of a single molecule in one direction - all channel proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

symport

A

movement of 2 molecules in the same direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

antiport

A

movement of 2 molecules in opposite directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

osmosis

A

diffusion of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

describe osmosis

A

water moves from an area of high water concentration to an area of low water concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

tonicity

A

the concentration of solutes in the environment surrounding the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

isotonic

A

the same - equal movement in and out of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

hypotonic

A

less concentration of solutes outside the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

hypertonic

A

concentration of solutes is more outside the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

osmotic lysis

A

animal cell bursts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

hypertonic red blood cell

A

crenation

26
Q

isotonic red blood cell

A

equilibrium

27
Q

hypotonic red blood cell

A

hemolysis

28
Q

plant cell in isotonic environment

A

flaccid - lacking firmness
(equilibrium)
water movement unable to provide cell with internal pressure necessary for structural support

29
Q

plant cell in hypotonic environment

A

rigid cell wall prevents plant cell from rupturing

high presure to provide structural stability

30
Q

turgor pressure

A

increrased internal pressure due to water entry provides structural support for plant

31
Q

tugidity

A

cell swelling

32
Q

plasmolysis

A

shrinking of plasma membrane and cytoplasm away from cell wall

33
Q

plant cell in hypertonic environment

A

water moves out of cell, cell wall maintains its shape but cell membrane and cytoplasm shrinks

34
Q

turgid plant

A

hypotonic solution

35
Q

isotonic solution

A

flaccid

36
Q

plasmolyzed

A

hypertonic solution

37
Q

active transport

A

movement against concentration gradient - low to high

38
Q

what does active transport require?

A

energy in the form of ATP and a transport protein called a pump

39
Q

what does ATP do in active transport

A

indices a conformational change in the protein pump to allow specific molecules to enter/exit cell against its concentration gradient

40
Q

what types of molecules does nulk membrane transport move?

A

transport of molecules in large quantity too large or too polar to pass through the membrane, onvolves the folding of the cell membrane to form a vesicle

41
Q

types of endocytosis

A

pinocytosis
phagocytosis
receptor mediated endocytosis

42
Q

phagocytosis

A

process by which living cells ingest other cells or large particles

43
Q

when does phagocytosis happen

A

found in simpler forms of life for feeding (like amoebas) used in higher order organisms as a defense mecahnism against invasion by foreign particles

44
Q

phagocyte

A

a white blood cell specialized for protecting the body by ingesting foreign substances

45
Q

describe the mechanism of phagocytosis

A
  • cell engulfs a particle by wrapping a psudopodia around it
  • enclosed in a large enough sac to be classified as a vacuole called a phagosome
  • hydrolytic enzymes in the lysosome digest the particle
  • residual body contains indigestible material which is eventually discharged by exocytosis
46
Q

lysosome

A

membrane bound sac of hydrolytic enzymes

47
Q

what pH does the lysosome enzyme work at best?

A

at pH 5

48
Q

how does the lysosome enzyme maindain acidic pH

A

pumps h+ into the lumen

49
Q

lysosome function is phagocytosis

A
  • fuse with food vacuole to digest food (like stomach in animals)
  • fuses iwth phagosome to breakdown microorganisms
50
Q

autophagy

A

lysosome recycles cell’s own organic material

51
Q

pinocytosis

A

ingestion of dissolved materials - “cellular drinking”

cell folds inwards to take in fluild containing the desired substance

52
Q

ingavinates

A

cell folds inwards to take in fluid

53
Q

ligand

A

a molecule that binds to a receptor

54
Q

receprot-mediated endocytosis

A

intake of molecules that bind specifically to a receptor on the surface of the cell

55
Q

where are receptor proteins usually found?

A

clustered in regions of the membrane called coated pits which contain coat proteins that help form vesicles for endocytosis

56
Q

describe the mechanism of receptor-mediated endocytosis

A
  • ligands bind to receptor
  • memrbane pinches to form vesicle
  • ligand detaches from receptor
  • vesicle pinch into 2 parts: free ligand and empty receptor
  • ligands fuse with lysosome
  • receptors returned to cell surface
57
Q

exocytosis

A

movement of materials from the cell to the cell surface within membrane bound vesicles

58
Q

how are the vesicles formed

A

off the golgi body of from endocytosis

59
Q

exocytosis function

A
  • secretion (release of waste, toxins, signaling molecules)
  • recycling of membrane proteins
  • restoring the cell memrbrane
60
Q
A