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Biology Unit 1 AS > Topic 3- Transport And Cell Membranes > Flashcards

Topic 3- Transport And Cell Membranes Flashcards

1
Q

How does the plasma membrane appear under a light microscope

A

As a double line

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2
Q

What are the two types of protein found in the plasma membrane

A

Intrinsic and extrinsic proteins

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3
Q

What are intrinsic proteins involved in

A

Transporting substances across the cell membrane

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4
Q

What are extrinsic proteins involved so

A

Act as receptors as they have a specific binding site, and are involved in cell to cell signalling and cell to cell recognition

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5
Q

What is the main function of the plasma membrane

A

Cell to cell recognition and cell to cell signalling

As well as controlling what substances enter and exit the cell

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6
Q

What is diffusion.

A

The movement of molecules from and area of high concentration to an area of low concentration down a concentration gradient

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7
Q

What molecules use simple diffusion

A

Lipid soluble molecules which are non polar and uncharged

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8
Q

Name substances that carry out simple lipid diffusion

A

Lipid soluble steroids
Oxygen
Carbon dioxide

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9
Q

What is facilitated diffusion

A

Passive transport of substances across a plasma membrane with the help of an intrinsic protein either through a carrier protein or a hydrophilic pore within a protein channel

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10
Q

What substances use facilitated diffusion

A

Large water soluble polar and charged molecules or ions

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11
Q

What are the two kinds of transport proteins

A

Channel proteins and Cartier proteins

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12
Q

What is active transport

A

An active process which moves against a concentration gradient from low to high concentration requiring an input of ATP energy

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13
Q

Name some examples of active transport

A

Transport of mineral ions in the root hair cells of plants

Glucose from kidney to the blood

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14
Q

How can active transport be stopped

A

By adding a metabolic poison called cyanide which stops the atp energy being produced, without atp active transport can not occur

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15
Q

How does phospholipids arrange themselves in water

A

As a Micelle, with the hydrophilic head facing outwards and the hydrophobic tails facing inwards

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16
Q

Why is structure of the plasma membrane described as a fluid mosaic structure

A

Fluid because all the parts move relative to each other and mosaic because all proteins are dotted through out the membrane like tiles

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17
Q

Describe the structure of the plasma membrane

A

Demi phospholipid bilayer composed of intrinsic and extrinsic proteins, glycolipids, glycoproteins and cholesterol arranged in a fluid mosaic structure

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18
Q

Who proposed the fluid mosaic structure of the plasma membrane

A

Singer and Nicholson

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19
Q

How are phospholipids arranged in water

A

As a Michelle with the hydrophilic heads outside and the hydrophobic heads facing in side

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20
Q

What are the main functions of the plasma membrane

A

Provide the cells structure, cell to cell signalling and cell to cell recognition

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21
Q

What does lipid bilayer mean

A

Two layers of phospholipid

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22
Q

What is a phospholipid

A

A molecule made of a hydrophilic glycerol phosphate head and two fatty acids forming a hydrophobic tail

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23
Q

What is the distance across the membrane

A

7-8 nm

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24
Q

How does an intrinsic protein differ from an extrinsic protein

A

Intrinsic proteins lie across both layers of the bilayer. Extrinsic proteins are in one of the layers on the surface of the membrane

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25
Q

What are intrinsic proteins

A

Proteins that lie across both the layers of the membrane

26
Q

What are extrinsic proteins

A

Lay in one layer of the membrane or on the surface of the membrane.

27
Q

What are glycoproteins

A

Proteins with a carbohydrate chain attached

28
Q

What are glycolipids

A

Lipids with a carbohydrate chain attached

29
Q

What are glycolipids involved with

A

Cell to cell recognition

30
Q

What are glycoproteins involved with

A

Cell to cell recognition

31
Q

What is the structure of the plasma membrane

A

A semi fluid phospholipid bilayer containing intrinsic and extrinsic proteins, glycoproteins and glycolipids and cholesterol

32
Q

Why is the plasma membrane selectively permeable

A

It is able to control what substances enter and exit the cell

33
Q

What is the role of cholesterol in the plasma membrane

A

Increase its rigidity

34
Q

Name the model proposed by singer and Nicholson

A

Fluid mosaic model

35
Q

What factors increase the rate of diffusion

A

Increasing temperature
Decreasing size
Increasing solubility in lipids
Increasing concentration

36
Q

What is facilitated diffusion

A

A form of diffusion where the molecules move from an area of high concentration to an area of low concentration down a concentration gradient via a carrier protein or a hydrophilic pre within A channel protein

37
Q

Does diffusion require ATP

38
Q

What are the two kinds of transport proteins

A

Carrier protein and a channel protein

39
Q

Draw a diagram to show diffusion

40
Q

Draw a picture to show facilitated diffusion

41
Q

Why is the partially permeable membrane important in osmosis

A

It ensures that large solutes do not diffuse and counteract the effect of osmosis

42
Q

What is osmosis

A

The movement of water molecules from a high water potential to a low water potential across a partially permeable membrane

43
Q

What is the equation that allows you to work out the water potential

A

¥cell = ¥s +¥p

44
Q

What is the water potential of pure water

45
Q

Describe the relationship between the water potential the pressure potential and the solute potential

A

The water potential is equal to the solute potential plus the pressure potential

46
Q

Is the highest possible water potential and what has this

A

Water and 0kpa

47
Q

What is the solute potential generated by

A

The solutes dissolved in the water

48
Q

What is the pressure potential generated by

A

THe cytoplasm pushing on the cell wall. As the cell wall is rigid it persists the pressure

49
Q

During osmosis what is the solution with the highest water potential known as

A

Hypotonic solution

50
Q

During osmosis what is the solution with the lower water potential called

A

Hypertonic

51
Q

What is the word that describes when bin solutions have the same water potential

52
Q

What happens when the solutions are isotonic

A

Both the solutions have the same water potential so there is no not movement

53
Q

What happens when a plant cell is placed in a hypertonic solution

A

The solution will loose water and become flaccid and plasmolysed

54
Q

What does plasmolysis mean

A

Where the cytoplasm shrinks and comes away from the cell wall causing the plant to wilt

55
Q

What happens when plant cells are placed on a hypotonic solution

A

They will gain water, swell and become turgid

56
Q

Why is it important that the cells become turgid

A

It ensures the plant will remain upright

57
Q

What happens to plant cells that are placed in a hypertonic solution

A

Loose water and become shrivelled

58
Q

What happens to animal cells when they are placed in a hypotonic solution

A

They will gain water swell and then burst

59
Q

What is incipient plasmolysis

A

The point at which the cytoplasm behind to come away from the cell wall

60
Q

How can incipient plasmolysis be found experimentally

A

Observing the solute potential at which half the plant cells in a sample are plasmolysis . At this point the solute potential is equal to the water potential - this is due to the pressure potential being zero as the cytoplasm is no knee pushing against the cell wall

61
Q

Draw a plant cell in a hypotonic isotonic and hypertonic solution

A

Draw and check text book

62
Q

Draw a plant cell in a hypotonic hypertonic and isotonic solution

A

Draw and check text book

Biology Unit 1 AS (6 decks)

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