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Grade 12 Biology > Membrane Structure > Flashcards

Membrane Structure Flashcards

1
Q

organs definition

A

specialized structure in the body that perform specific life processes

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2
Q

organelles definition

A

specialized structures inside the cell that perform specific cellular processes

often surrounded by a membrane

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3
Q

cell fractionation

A

a method of separating cell parts to study their function

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4
Q

homogenization definition

A

the disruption of cell membrane without damaging organelle

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5
Q

centrifuge

A

instrument that spins a high speeds to spearate contents by density

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6
Q

4 ways to rupture the plasma membrane

A
  • break cells with high frequency
  • use a mild detergent
  • use high pressure by forcing cells through a small hole
  • shear cells between a close fitting rotating plunger
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7
Q

steps to cell fractionation

A
  1. homogenize
  2. centrifuge
  3. decant supernatant
  4. repeat centrifugation at higher speeds to separate into smaller components
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8
Q

pellet

A

larger, more dense components of tissue

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9
Q

supernatant

A

lighter suspended in liquid above the pellet in tissue

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10
Q

plasma membrane

A

aka cell membrane all cells and organelles are surrounded by it

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11
Q

what is the membrane composed of?

A
  • phspholipids
  • membrane proteins (integral, peripheral)
  • carbohydrates
  • cholesterol
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12
Q

what is each layer called in a phospholipid bilayer

A

leaflet

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13
Q

what environment is the phospholipid bilayer in?

A

water is on both sides -> cell is in water environment and the cell interior is also a water environment (polar)

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14
Q

how is the phospholipid arraged in the phospholipid bilayer

A
  • hydrophobic tails face inward forming a hydrophobic core
  • hydrophilic heads face outwards
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15
Q

what are the two locations classification of membrane proteins

A

integral, peripheral

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16
Q

what are the classification of integral proteins

A
  • polytopic transmembrane, sinlge-pass, multi-pass
    -monotopic
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17
Q

what are the classifications of peripheral proteins

A
  • extracellular
  • intracellular
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18
Q

what does polytopic mean?

A

faces both sides of membrane

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19
Q

transmembrane definition

A

spans entire phospholipid bilayer

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20
Q

single pass protein definition

A

crosses membrane once

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21
Q

multi-pass protein definition

A

crosses membrane several times

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22
Q

monotopic definition

A

associated with membrane on one side, does not span entire bilayer

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23
Q

how are non peripheral mombrane proteins bound?

A

non-covalently to either surface of the membrane

does NOT enter the leaflet

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24
Q

functions of membrane proteins

A
  • receptor
  • enzymatic activity
  • recognition
  • attachment
  • transport
  • cell adhesion
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25
types of transmembrane proteins
- receptor protein - channel protein - gated channel protein - transport protein - glycroprotein protein
26
receptor protein
has a binding site to fit the molecule which acts as a chemical signal/messenger,
27
result of binding in receptor protein
causes a conformational change in receptor protein, which results in a relaying message to the interior of the cell
28
enzymatic activity
protein has a binding sit for molecule, binding results in a chemical reaction that changes the substrate to a new product
29
recognition protein
glycoprotein, surface carbohydrate groups help identifycell (eg antigens)
30
what does an attachment protein attach to?
interior cytoskeleton, exterior extacellular matrix (ECM)
31
what does the attachment protein do?
provide structural support
32
where does the extracellular cell face?
exterior/outside of the cell
33
what do extracellular proteins attach to?
the extracellular matrix, ECM
34
what is the fuction of ECM(extracellular matrix)
- supports cell structure - anchors cell - separates tissues - functions in cell signalling
35
components of ECM
a matrix of glycoproteins secreted by cells, it varies with type of tissue
36
where are intracellular proteins attached?
inner membrane surface
37
what do intracellular cytoskeleton protein attach to?
cytoskeleton of cell
38
describe the intracellular cytoskeleton
a network of fibers extending throughout the cytoplasm
39
what does it mean by the intracellular cytoskeleton being dynamic
can be quickly dismantled and reassembled in a new location
40
what are the functions of the cytoskeleton
- mechanical support to cell - cell motility
41
how does cytoskeleton support cell structure?
- anchorage for organelles - maintain cell shape critical for animal cells as there is no cell wall
42
what does motility of a cell mean in regards to the cytoskeleton
movement of cell -> change in cell location movement of parts, vesicles, chromosomes, etc
43
what are the components of the cytoskeleton
- micro filament - actin - intermediate filament - microtubules - tubulin
44
types of transport proteins
channel, carrier/pump
45
types of channel transport protein
ungated, gated
46
describe the channel proteins
- act like tunnels - molecules move through protein passively
47
what types of particles to channel proteins move?
small molecules or charged ions
48
describe an ungated channel protein
always opened aka leak channels
49
describe a gated channel protein
has open and closed conformations changes stimulated by changes in external environment,
50
describe the carrier/pump proteins
- acts like turnstile - undergoes conformational change to allow molecules through
51
what does it mean by cell adhesion proteins
structures that connect cell to cell, in animal cells
52
what are the types of cell adhesion proteins
- channel-forming - ocluding junction - anchoring junction
53
describe the channel forming protein
provides channel between adjacent cells for passage of small molecules and ions
54
describe the occluding junction protein
fuses membranes of adjacent cells, forms impermeable barrier between cells
55
what is another name for anchoring proteins
desmosome
56
describe the anchoring/desmosome proteins
desmosomes bind to desmosomes on adjacent cell
57
what does a desmosome do?
helps resist shearing force when cells are under mechanical stress
58
where are desmosomes attached?
cytoskeleton
59
what is the name of occluding proteins?
tight junctions
60
what is the name of channel forming proteins?
gap junctions
61
example of gap junction attachements
muscle tissue
62
example of tight junction attachment
intestinal lining
63
example of desmosome
bladder tissue
64
functions of integral proteins
receptor, enzymatic activity, recognition, attachment, transport, cell adhesion
65
peripheral protein functions
recognition attachment
66
glycoprotein makeup
carbohydrate + protein
67
glycolipid makeup
carbohydrate + lipid (phospholipid)
68
where are carbohydrates relative to the cell
extracellular
69
what are the function of cell surface carbohydrates?
- identifies the cell, helping other cells recognize it - acts as a signal for communication
70
what is membrane fluidity affected by?
- saturation of fatty acid - hydrophobic restrictions - cholesterol and temperature
71
what are the types of movement within the membrane?
- lateral diffusion - rotation - swing - flexion
72
what is lateral diffusion movement within a membrane?
movement accross the same leaflet (phospholipids transpose with neigboring molecules)
73
what is rotation movement within a membrane?
when a individual molecule rotates quickly around its axis
74
what is swing movement within a membrane?
from side to side
75
what is flexion movement within a membrane?
contraction movement
76
transverse diffusion aka...
flip flop
77
transverse diffusion
movement from one leaflet to another
78
what enzyme facilitates transverse diffusion
flippase
79
why is transverse diffusion rare?
the hydrophilic head of phospholipid must go cross the hydrophobic core to get the leaflet
80
properties of cholesterol
large molecular size and non polar
81
what is the impact of cholesterol having a large molecular size
can interrupt intermolecular forces of attraction
82
83
what is the impact of cholesterol being non polar
stabilizes hydrophobic interactions
84
what does cholesterol do at a low temperature?
the phospholipid moves around less, squeezes phospholipids and increases fluidity -> large molecular size
85
what does cholesterol do a high temperature?
pulls together the bilayer -> non polar
86

Grade 12 Biology (30 decks)

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