Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Building blocks of life > transport into and around the cell > Flashcards

transport into and around the cell Flashcards

1
Q

what is the function of a membrane?

A

separates cells from their external environment

also defines spaces

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

functions of membranes

A 
transport
enzyme activity
signal transduction
intercellular joining
cel recognition
attachment to ECM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the membrane structure?

A 
very thin 
2 molecules thick 
forms a closed boundary
made of lipids
proteins embedded in the layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why are proteins found in membranes

A

give the membrane function and ability to do certain tasks

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

what is a bacteria membrane like?

A

can have multiple ones and cell walls

different composition but same lipids

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

what are virus membranes like?

A

enveloped viruses with lipid layer from the cell in infected

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

how does the fluid mosiac model describe membranes?

A

a mix of lipids in layer that move around in flux
proteins are embedded within too
membrane is flexible

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

what is the evidence for the fluid mosaic model?

A

surface tension of the membrane did not match that of lipid only models but did match when proteins added

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

how did evidence for the fluid modaic model come about?

A

fused mouse and human cellls together in a hybrid

proteins mixed and moved therefore they are fluid and can move proving the fluid mosaic modeel

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

examples of lipids

A

cholesterol
phospholipids
glycolipids

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

what is special aboout lipids?

A

each organ and organelles has a differnt composition of them and the types

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

why is pH key for membranes?

A

ensures head groups are in their ionised charged form and thus suitably hydrohobic

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

what is self assembely?

A

if phospholipids are added to a tube of water a neural pH they will spontaneously form a closed bilayer in structures called liposomes

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

what is a phospholipid?

A

phosphate containing two lipids

two fatty acid chains with a glycerol backbone

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

what is the difference between a phosphoglyceride and a sphingolipid?

A

phosphoglyceride is glycerol base lipid

sphingolipid is sphingosine bases lipid

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

if the membrane is too cold and rigid what changes does it make?

A

more unsaturated lipids, adds kinks to the tail to space out molecules
proteins can move around and membranes become more fluid

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

if the membrane is too hot and fluid what changes does it make?

A

lipids become more saturates and packed more tightly making the membrane more fluid

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

what does adding cholesterol to a membrane do?

A

controls the fluidity of the membrane

but too much makes it rigid and viscous

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

how is the membrane asymmetrical

A

outer layer is different to inner

eg receptors

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

what are found on the outside of the membrane?

A

glycolipids

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

what is a glycolipid?

A

sugar group headed lipid

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

what is the function of a glyocolipid

A

provides protection for the cell sugar coating.

helps with ice crystals and stresses

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

what is found on the inside of the membrane?

A

phosphatidylserine

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

what is the function of phosphatidylserine

A

signal molecules
flips over during death signals to act as the signalling molecules for death and that the cell needs to be engulfed and disposed of
process called flip-flop

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

what causes flip-flop movement?

A

very rare

enzymes called flippases can sometimes do this but its never spontaneous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how does the membrane have an electrical charge?

A

inside the cell are proteins and ions that at a neural pH have a new negative charge
the ions move in and out of the cell to balance this charge out
causes and electrochemical gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what is the gradient in a cell

A

positive outside

negative inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

why is the electrical gradient in cells so important?

A

nerve signal transmission requies it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what does the membrane favour in terms of ions?

A

transport of cations into the cell

anions out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

how do things move across the membrane?

A

it is selectively permeable

highly controlled what goes in and out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what can and cant go across membranes

A

hydrophobic moecules cant disolve

sugars are repelled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what facilitates movement of thing across the membrane

A

transport proteins

channel proteins

33
Q

why are transport protens used?

A

a hydrophillic substance that cant go through on their own

34
Q

what transport water?

A

aquaporins

35
Q

how do carrier proteins work?

A

bind to molecules and change shape to shuttle things across the membrane
not open all the time, specific
works down a concentration gradient, passive

36
Q

what is passive transport?

A

diffusion

carrier proteins

37
Q

how does active transport work>

A

against a concentration gradient

requires energy in form of ATP

38
Q

what do cells contain that remain largely trapped within the cell?

A 
sugar
protein
amino acids
nucleotides
ions
39
Q

because there are lots of things within the cell it creates a what gradient?

A

strong osmotic gradient

meanign water will move into the cell

40
Q

how is the osmotic gradient controlled?

A

Na/K pump

41
Q

how does the Na/K pump work?

A

pumps out some ions
open on the outside and removes sodium through ATP
open on the inside too allowing K to bind
3Na out for every 2K in
net loss from cell and equalibrium made

42
Q

why is endocytosis used in cells?

A

cant have large channels for large molecules because then everything smaller would also flow through
so endocytosis is used

43
Q

describe the process of receptor-mediated endocytosis

A
  1. ligand binds to membrane receptor
  2. receptor-ligand migrates into clathrin-coated pill, membrane pulls molecule into cell
  3. endocytosis
  4. endosome/vehicle made with molecule inside losing clathrin coat
  5. enzymes degrade lipids
44
Q

how does the process of coated vesicles in endocytosis work?

A

ligand binds to receptor

membrane curves a proteins bind to inside of receptor fitting together to form a circle endosome

45
Q

in a coated vesicle endosymbiosis what is the endosome coated in?

A

clathrin molecule forms a cage/coat

46
Q

what is pinocytosis?

A

takes in little bits of the environment

47
Q

how are proteis secreted?

A

transported to the plasma membrane in vesicles which then fuse with the membrane releasing their contents

48
Q

what balance keep cells shrinking?

A

endocytosis and exocytosis

49
Q

where are proteins synthesised?

A

rough ER

50
Q

where are proteins packaged?

A

golgi body

51
Q

what are the two pathways for a substance to be secreted?

A

constitutive secretory pathway

regulated secretory pathway

52
Q

how does the constitutive secretory pathway work?

A

used immediately and constantly made
used for molecules to be secreted as soon as they are made
the molecule is packaged and sent to surface quickly to be secreted
the membrane fusion is unregulated

53
Q

how does the regulated secretory pathway work?

A

the packaged molecule stays around for a while
it is stored and only released when it recieves the correct signal such as a hormone or neurotransmitter
made in advance to save time

54
Q

how do viruses exploit membrane transport

A

use the host membrane to get in and out of the cell
ligands on virus cell iminates the cells ones
fools the cells and allows it to undergo endocytosis
enzymes on the virus protect it from being degrades
budd out taking some membrane with it

55
Q

what helps viruses fool cells?

A

ligands on surfaces and lipids

56
Q

what are cellular membranes and why are they imporant

A

golgi and ER
key to move things around the cell once inside
compartmentalisation of cells

57
Q

how do proteins end up where they need to be?

A

labels on they act as tags to signal where they need to be sent

58
Q

what signal sends a protein to the nucleus?

A

lys-lys-lys-arg-lys

59
Q

how can proteins be modified after being made

A

glycosylated
phosphylation
ubiqunation

60
Q

a glycosylated protein goes where?

A

plasma membrane

61
Q

a phosphylated protein can do what?

A

change what it can bind to

62
Q

what does unbinquination do to a molecule?

A

sends the protein for break down in the proteosome

63
Q

how can you move things between compartments

A

gated transport
transmembrane transport
vesicles

64
Q

how does gated transport work?

A

eg nuclear pore
acts like a channel proteins allowing large things through
needs sequence tagging to work

65
Q

how does transmembrane transport work

A

cant have a large pore to move proteins so this allows single amino acids through at a time
acts as a proteins translocator an the peptide chain is fed through

66
Q

example of transmembrane transport

A

mitochondria

moving cytochrome C around

67
Q

exmple of vesicular transport

A

motor proteins

68
Q

why is vesicular transport needed?

A

vesicles need to be moved around the cell to they are waked down microtubues

69
Q

three types of motor proteins used to transport vesicles?

A
  1. myosin
  2. kinesin
  3. dynein
70
Q

which motor protein used actin filaments?

A

myosin

71
Q

which motor proteins use microtbules

A

kinesin and dynein

72
Q

which motor protein moves things towards the edge of the cell

A

kinesin

73
Q

which motor protein moves things towards the middle of the cell?

A

dynein

74
Q

what do motor proteins move?

A

vesicles and whole organelles

drag chromosomes durig mitosis

75
Q

what do endosomes use to move?

A

dynein

76
Q

what do secretory vesicles use to move?

A

kinesin

77
Q

how do nerve cells use motor proteins?

A

transmitting nerve signals they need they neurotransmitter down the other end to where its mad
use mtoro proteins to move it where its needed

78
Q

what do motor proteins require to work?

A

ATP

79
Q

structure of a motor protein

A

head/feet
stalk
tail attaches to the molecules to be moved
add ATP to head/ foot to move in a step like way

Building blocks of life (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions