Lipids and Membranes Flashcards

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1
Q

What is a plasma memebrane?

A

The bounday that seperates the living cell from its surroundings

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2
Q

What does the plasma membrane serve as?

A

A selective barrier that allows chemical reactions to ocur effectively.

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3
Q

What is the most abundant lipid in the plasma membrane?

A

Phospholipiods

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4
Q

What is the structure of a phospholipid?

A

The hydrophilic head, which is “attracted” to water and the hydrophobic head, which “hides” from water

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5
Q

What do phospholipids self asmenble to form?

A

Bubbles or micelle to form phosphlipid layers

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6
Q

What building block moves less than phospholipids within the bilayer?

A

Proteins

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7
Q

What kind of movement do unsaturated hydrocarbon tails have?

A

Fluid/rougher

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8
Q

What kind of movement does saturated hydrocarbon tails have?

A

Viscous movement

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9
Q

What is used in place of cholesterol for plants?

A

Sterols

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10
Q

What is cholesterol used for?

A

It provides stability and acts as a temperature buffer quality for the membranee. Sterols for plants

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11
Q

What model does the plasma membrane have?

A

The fluid-mosaic model

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12
Q

What is the fluid phospholipid layer?

A

It is a layer where transmembrane proteins are partially or completely embedded, creating semi-permeable channels.

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13
Q

What are the classes of membrane proteins?

A

Peripheral proteins and integral proteins

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14
Q

What are peripheral proteins?

A

Proteins loosely bound to the surface of the membrane

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15
Q

What are integral proteins?

A

Proteins that penetrate the lipid bilayer across the whole membrane

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16
Q

What is another name for integral proteins?

A

Transmembrane proteins

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17
Q

What type of protein is antigen?

A

A peripheral protein

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18
Q

What type of protein are transport proteins?

A

Intergral Proteins

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19
Q

What is the function of channel proteins?

A

Wide open passages

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20
Q

What is the function of ion channels?

A

Gated passges

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21
Q

What is the function of aquaporins?

A

Only lets water

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22
Q

What is the function of carrier proteins?

A

Changes shape

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23
Q

What is the function of transport proteins?

A

Requires ATP

24
Q

What are glycoproteins?

A

Recognition proteins

25
Q

What are hormones?

A

Receptor proteins

26
Q

What is the function of adhesion proteins?

A

Anchors

27
Q

Who discovered aquaporins?

A

Peter Agre (1991) and Roderick McKinnon (2003)

28
Q

Why are proteins the perfect molecule to build structures?

A

They alter structure and function

29
Q

What does a plasma membrane have to do to be a selectively permeable barrier?

A

A plasma membrane needs to import ions and molecules necessary for life while excluding ions and moleales that might damage it.

30
Q

What can be found inside the plasma membrane that anchors proteins?

A

Hydrophobic non polar amino acids

31
Q

What is found on the outer surfaces of membrane in fluid?

A

Hydrophobic polar amino acids

32
Q

What are the molecules that can get through the plasma membrane?

A

Hydrophobic molecules eg oxygen, carbon dioxide, nitrogen, steroids and small uncharged polar molecules eg water, glycerol, urea

33
Q

What are molecules that can’t get through the plasma membrane directly?

A

Large uncharged polar molecules eg glucose, sucrose and ions (positive or negative)

34
Q

What are the ways of getting through the cell membrane?

A

Passive transport, facilitated transport and active transport

35
Q

What are the two ways of going from high to low concentration?

A

Passive and facilitated transport

36
Q

What is passive transport?

A

The diffusion of hydrophobic molecules (lipids)

37
Q

What is facilitated transport?

A

The diffusion of hydrophilic molecules through a protein channel

38
Q

What is the difference between passive transport and facilitated transport?

A

Passive transport is done on its own and facilitated transport is done with help.

39
Q

What is active transport?

A

The diffusion against the concentration gradient from low concentration to high concentration. Uses a protein pump and requires ATP

40
Q

What law is diffusion applied to?

A

The 2nd law of thermodynamics

41
Q

What helps facilitated diffusion?

A

Channels for ions/water and carriers for sugars/amino acids

42
Q

How do proteins open in the gated channels?

A

They only open in the presence of stimulus.

43
Q

’ How are large molecules usually moved in and out of cells?

A

Through vesicles and vacuoles and endocytosis or exocytosis

44
Q

What is phagocytosis?

A

Cellular eating

45
Q

What is pinocytosis?

A

Cellular drinking

46
Q

What is osmosis?

A

The diffusion of water from high concentration to low concentration that occurs only when solutions are separated by a membrane that permits wate to cross but holds back some or all solutes

47
Q

What is the solute concentration for hypertonic solutions?

A

More solute, less water

48
Q

What is the solute concentration for hypotonic solutions?

A

Less solute more water

49
Q

What is the solute concentration for isotonic solutions?

A

Equal amount of solute and water.

50
Q

What does cell survival depend on?

A

Balancing water uptake and loss

51
Q

How are plant cells and animal cells in hypotonic solutions?

A

Animal cells- Lysed and burst while plants were turgid and normal

52
Q

How are plants and animals in isotonic solutions?

A

Animal cells are normal and plant cells are flaccid

53
Q

How are plants and animals in hypertonic solutions?

A

Animal cells are shriveled while plant cells are plasmolyzed

54
Q

What are salt water organisms compared to their environment?

A

Hypotonic

55
Q

Where are transmembrane proteins embedded?

A

In the fluid phospholipid layer

56
Q

What creates semi-permeable channels?

A

The embedding of transmembrane proteins in the phospholipid layer