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BIO 120 > CP 4 Cell Membranes and Signalling > Flashcards

CP 4 Cell Membranes and Signalling Flashcards

1
Q

describe the fluid mosaic model

A

○ Plasma memb is fluid mosaic of lipids and proteins
○ Fluid lipid bilayer, proteins float freely

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2
Q

What are peripheral proteins

A

○ Only interact with polar head groups of bilayer
○ Don’t go all the way thru like the other proteins

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3
Q

TF lipids are not good insulators

A

F Lipids r very good insulators

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4
Q

What is the Protein-Lipid composition in: nerve insulation

A

More lipids less proteins

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5
Q

What is the Protein-Lipid composition in: The plasma membrane

A

pretty much 1;1

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6
Q

What is the Protein-Lipid composition in: Electron transport

A

More proteins less lipids

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7
Q

TF phosplolipids are amphipathic (hydrophilic end and hydrophobic end)

A

T

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8
Q

What is the phospholipid structure

A

1 phosphorus and 3 fatty acids

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9
Q

TF the bilayer structure depends on the lipid concentration

A

T

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10
Q

TF the membrane monolayers have different composition

A

T,
External: Glycolipids, carbs, receptor proteins
Internal: Cytoskeleton

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11
Q

what happens to a cell if the cell fluidity is low

A

membrane turns gel-like, could die

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12
Q

What happens to a cell if the membrane fluidity is too high

A

Allows potentially dangerous molecules to get thru

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13
Q

TF unsaturated hydrocarbon tails are Viscous

A

F, they r fluid

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14
Q

TF saturated hydrocarbon tails r fluid

A

F, they r viscous

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15
Q

TF the longer the fatty acid tail the more viscous the membrane

A

T

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16
Q

What is the name of the enzyme that takes H+ from unsaturated fatty acid to make a double C bond

A

Desaturase

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17
Q

What is desaturase used for

A

to increase membrane fluidity

18
Q

A higher temperature ______ membrane fluidity

A

increases

19
Q

What are the 3 Major factors to membrane fluidity

A

1) structure of phospholipid tails
2) Temperature
3) Cholesterol levels

20
Q

How is cholesterol arranged

A
  • Arranged the same way as phospholipids
    ○ Head outwards and tail inside
    • Hydrophilic head and hydrophobic tail
21
Q

What is a function of cholesterol

A

Act as a buffer

22
Q

In higher temps, cholesterol will ______ fluidity and ______ movement of lipids

A

Reduce
Restrain

23
Q

In lower temps, cholesterol will ______ fluidity and ______ lipids from gelling

A

Increase
Prevent

24
Q

what is the difference between integral anf peripheral membrane protiens

A

Integral membrane proteins
- Contains hydrophobic domains that cross the bilayer
- Transmembrane domain
○ Has stretches of non-polar amino acids

Peripheral proteins
- Sits on the surface and form noncovalent bonds with lipids and membrane proteins
- Has no interaction with hydrophobic core

25
Q

what r 4 diff types of proteins we see in the membrane

A

transporters
enzymes
signal transduction
attachment

26
Q

what do transporter protiens do

A

Provides channel for movement of molecules

27
Q

how does an enzyme work in the membrane

A

Substrate binds to active site on enzyme

28
Q

What are the steps to Signal Transduction

A

Reception –> Transduction –> Response

29
Q

What is the function of attachment protiens

A

Cytoskeleton and cell to cell recognition

30
Q

What are the different types of transport

A

Active
Passive

31
Q

What are the characteristics of passive transport

A
  • Requires no energy
  • Moves from high to low concentration
32
Q

what is facilitated diffusion

A
  • type of passive transport
    ○ Large, uncharged polar molecs need carrier proteins to get thru
    ○ Channel proteins are corridors in memb. To allow a specific molec to pass (some gated or volt)
33
Q

What are the characteristics of Active Transport

A
  • Dragged across concent. gradient so it req ATP
    ○ Moves Na out and K in (both against their concent gradient)
    ○ Proton pump, Keeps pH low, Generates membrane potential
34
Q

What is secondary active transport

A

○ Use ion gradients created by primary active transport
○ Coupled with primary pump

35
Q

What is Cotransport

A

2 solutes moving together

36
Q

what is antiport

A

Transported solute moves in the direction opposite from the gradient driving ion

37
Q

why is active transport needed

A
  • Uptake of essential nutrients at lower extracellular concentration
  • Removal of secretory waste at higher extracellular concent.
  • Maintain constant intercellular concentrations of Na, H, K, Ca
  • Maintain membrane potential (voltage difference across plasma memb.)
38
Q

what is osmosis

A
  • Type of passive diffusion that applies to water molecules
  • Moves from high to low concent across a selectively permeable membrane
39
Q

what is the plant versions of:
isotonic
hypotonic
hypertonic

A

Flaccid
Plasmolysis
Turgid

40
Q

what is Tonicity

A

he cells ability to gain and lose water

BIO 120 (10 decks)

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