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Flashcards in 1.5: Lipids Deck (99):
1

Lipids are a varied group of substances that share the following characteristics:

1. They contain what?

Lipids contain:

1. Carbon

2. Hydrogen

3. Oxygen

2

Lipids are a varied group of substances that share the following characteristics:

1. Lipids contain carbon, hydrogen and oxygen.

2. The proportion of oxygen to carbon and hydrogen is what?

The proportion of oxygen to:

1. Carbon

2. Hydrogen

is smaller than in carbohydrates

3

Lipids are a varied group of substances that share the following characteristics:

1. Lipids contain carbon, hydrogen and oxygen.

2. The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.

3. They are what in water?

Lipids are insoluble in water

4

Lipids are a varied group of substances that share the following characteristics:

1. Lipids contain carbon, hydrogen and oxygen.

2. The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.

3. Lipids are insoluble in water.

4. They are soluble in what?

Lipids are soluble in organic solvents

5

Lipids are a varied group of substances that share the following characteristics:

1. Lipids contain carbon, hydrogen and oxygen.

2. The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.

3. Lipids are insoluble in water.

4. They are soluble in organic solvents, such as what?

Lipids are soluble in organic solvents, such as:

1. Alcohols

2. Acetone

6

The main groups of lipids are what?

The main groups of lipids are:

1. Triglycerides

2. Phospholipids

7

The main groups of lipids are triglycerides, which are what, and phospholipids?

The main groups of lipids are triglycerides:

1. Fats

2. Oils

,and phospholipids

8

Triglyceride

A triglyceride is an individual lipid molecule made up of:

1. A glycerol molecule

2. 3 fatty acids

 

9

Fats are generally made of what fatty acids?

Fats are generally made of saturated fatty acids

10

Fats are generally made of saturated fatty acids, while oils are made of what?

1. Fats are generally made of saturated fatty acids

,while

2. Oils are made of unsaturated fatty acids

11

Fats are generally made of saturated fatty acids, while oils are made of unsaturated fatty acids.

Fats are solid at room temperature, whereas oils are what?

1. Fats are solid at room temperature

,whereas

2. Oils are liquid

12

Lipids have many roles.

One role of lipids is in cell what?

One role of lipids is in cell membranes

13

Lipids have many roles.

One role of lipids is in cell membranes, as what?

One role of lipids is in cell membranes, as:

1. Cell-surface membranes

2. Membranes around organelles

14

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the what of cell membranes?

Phospholipids contribute to the flexibility of cell membranes

15

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of what across them?

Phospholipids contribute to the:

1. Flexibility of cell membranes

2. Transfer of lipid-soluble substances across them

16

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of what?

Lipids are a source of energy

17

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, what do lipids do?

When oxidised, lipids:

1. Provide more than twice the energy as the same mass of carbohydrate

2. Release valuable water

18

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be what?

Lipids can be waterproofing

19

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have what?

 

Both plants and insects have:

1. Waxy

2. Lipid

cuticles

20

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that do what?

Both:

1. Plants

2. Insects

have waxy, lipid cuticles that conserve water

21

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing. Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce what?

Both:

1. Plants

2. Insects

have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin

22

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing. Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for i?

Lipids can be used for insulation

23

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of what?

Fats are slow conductors of heat

24

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing. Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of heat and when stored beneath the body surface help to do what?

Fats are slow conductors of heat and when stored beneath the body surface help to retain body heat

25

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of heat and when stored beneath the body surface help to retain body heat.

Lipids also act as electrical insulators where?

Lipids also act as electrical insulators in the myelin sheath around nerve cells

26

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of heat and when stored beneath the body surface help to retain body heat.

Lipids also act as electrical insulators in the myelin sheath around nerve cells.

4. Lipids can be used for p?

Lipids can be used for protection

27

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of heat and when stored beneath the body surface help to retain body heat.

Lipids also act as electrical insulators in the myelin sheath around nerve cells.

4. Lipids can be used for protection.

Fat is often stored where?

Fat is often stored around delicate organs

28

Lipids have many roles.

One role of lipids is in cell membranes, as cell-surface membranes and membranes around organelles.

Phospholipids contribute to the flexibility of cell membranes and the transfer of lipid-soluble substances across them.

Other roles of lipids include:

1. Lipids are a source of energy.

When oxidised, lipids provide more than twice the energy as the same mass of carbohydrate and release valuable water.

2. Lipids can be waterproofing.

Lipids are insoluble in water and therefore useful in waterproofing.

Both plants and insects have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin.

3. Lipids can be used for insulation.

Fats are slow conductors of heat and when stored beneath the body surface help to retain body heat.

Lipids also act as electrical insulators in the myelin sheath around nerve cells.

4. Lipids can be used for protection.

Fat is often stored around delicate organs, such as what?

Fat is often stored around delicate organs, such as the kidney

 

29

Room temperature

Room temperature is 10 - 20 degrees Celsius

30

Triglycerides are so called because they have what?

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride)

31

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride).

Each fatty acid does what?

Each fatty acid in triglycerides forms an ester bond with glycerol in a condensation reaction

32

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride).

Each fatty acid forms an ester bond with glycerol in a condensation reaction.

Hydrolysis of a triglyceride therefore produces what?

Hydrolysis of a triglyceride therefore produces:

1. 3 fatty acids

2. Glycerol

33

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride).

Each fatty acid forms an ester bond with glycerol in a condensation reaction.

The 3 fatty acids may all be the same, thereby forming a what?

The 3 fatty acids may all be the same, thereby forming a simple triglyceride

34

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride).

Each fatty acid forms an ester bond with glycerol in a condensation reaction.

The 3 fatty acids may all be the same, thereby forming a simple triglyceride or the 3 fatty acids may be different, in which case what is produced?

The 3 fatty acids may:

1. All be the same, thereby forming a simple triglyceride

Or,

2. Be different, in which case a mixed triglyceride is produced

35

Triglycerides are so called because they have 3 (tri) fatty acids combined with glycerol (glyceride).

Each fatty acid forms an ester bond with glycerol in a condensation reaction.

The 3 fatty acids may all be the same, thereby forming a simple triglyceride or the 3 fatty acids may be different, in which case a mixed triglyceride is produced.

In either case, it is what?

In either case, it is a condensation reaction

36

The glycerol molecule in all triglycerides is what?

The glycerol molecule in all triglycerides is the same

37

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from what?

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different:

1. Fats

2. Oils

come from variations in the fatty acids

38

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are how many different fatty acids?

There are over 70 different fatty acids

39

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have what?

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached

40

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.

If this chain has no carbon-carbon double bonds, the fatty acid is then described as what?

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated

 

41

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because what?

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms

 

42

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms.

In other words, all the carbon atoms are what?

In other words, all the carbon atoms are saturated with hydrogen atoms

 

43

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms.

In other words, all the carbon atoms are saturated with hydrogen atoms.

If there is a single double bond, the fatty acid is what?

If there is a single double bond, the fatty acid is mono-unsaturated

 

44

As the glycerol molecule in all triglycerides is the same, the differences in the properties of different fats and oils come from variations in the fatty acids.

There are over 70 different fatty acids and all have a carboxyl (-COOH) group with a hydrocarbon chain attached.

If this chain has no carbon-carbon double bonds, the fatty acid is then described as saturated, because all the carbon atoms are linked to the maximum possible number of hydrogen atoms.

In other words, all the carbon atoms are saturated with hydrogen atoms.

If there is a single double bond, the fatty acid is mono-unsaturated.

If more than one double bond is present, the fatty acid is what?

If more than one double bond is present, the fatty acid is polyunsaturated

 

45

Polyunsaturated, more than one double bond between carbon atoms.

The double bonds cause the molecule to do what?

The double bonds cause the molecule to bend

 

46

Polyunsaturated, more than one double bond between carbon atoms.

The double bonds cause the molecule to bend.

They cannot therefore do what?

The molecules cannot therefore pack together so closely

47

Polyunsaturated, more than one double bond between carbon atoms.

The double bonds cause the molecule to bend.

The molecules cannot therefore pack together so closely, making them what?

The molecules cannot therefore pack together so closely, making them liquid at room temperature

 

48

Polyunsaturated, more than one double bond between carbon atoms.

The double bonds cause the molecule to bend.

The molecules cannot therefore pack together so closely, making them liquid at room temperature.

Example

For example, they are oils

49

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of what?

Triglycerides have a high ratio of:

1. Energy-storing carbon-hydrogen bonds

to

2. Carbon atoms

50

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of what?

Triglycerides:

1. Have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms

2. Are therefore an excellent source of energy

51

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low what?

Triglycerides have a low:

1. Mass

to

2. Energy

ratio

52

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good what?

Triglycerides have a low mass to energy ratio, making them good storage molecules

53

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because what?

Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume

54

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it what?

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around

55

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around.

3. Being large, non-polar molecules, triglycerides are what?

Being:

1. Large

2. Non-polar

molecules, triglycerides are insoluble in water

56

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around.

3. Being large, non-polar molecules, triglycerides are insoluble in water.

As a result, their storage does not affect what?

As a result, their storage does not affect:

1. Osmosis in cells

Or,

2. The water potential of them

57

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around.

3. Being large, non-polar molecules, triglycerides are insoluble in water.

As a result, their storage does not affect osmosis in cells or the water potential of them.

4. As triglycerides have a high ratio of hydrogen to oxygen atoms, they do what when oxidised?

As triglycerides have a high ratio of:

1. Hydrogen

to

2. Oxygen

atoms, they release water when oxidised

58

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around.

3. Being large, non-polar molecules, triglycerides are insoluble in water.

As a result, their storage does not affect osmosis in cells or the water potential of them.

4. As triglycerides have a high ratio of hydrogen to oxygen atoms, they release water when oxidised and therefore provide an important source of what?

As triglycerides have a high ratio of hydrogen to oxygen atoms, they:

1. Release water when oxidised

2. Therefore provide an important source of water

59

The structure of triglycerides related to their properties:

1. Triglycerides have a high ratio of energy-storing carbon-hydrogen bonds to carbon atoms and are therefore an excellent source of energy.

2. Triglycerides have a low mass to energy ratio, making them good storage molecules, because much energy can be stored in a small volume.

This is especially beneficial to animals, because it reduces the mass they have to carry as they move around.

3. Being large, non-polar molecules, triglycerides are insoluble in water.

As a result, their storage does not affect osmosis in cells or the water potential of them.

4. As triglycerides have a high ratio of hydrogen to oxygen atoms, they release water when oxidised and therefore provide an important source of water, especially for who?

As triglycerides have a high ratio of hydrogen to oxygen atoms, they:

1. Release water when oxidised

2. Therefore provide an important source of water, especially for organisms living in dry deserts

60

Water potential

Water potential is the:

1. Pressure created by water molecules

2. Measure of the extent to which a solution gives out water

61

Water potential is the pressure created by water molecules and the measure of the extent to which a solution gives out water.

The greater the number of water molecules present, what?

The greater the number of water molecules present, the higher (less negative) the water potential

62

Water potential is the pressure created by water molecules and the measure of the extent to which a solution gives out water.

The greater the number of water molecules present, the higher (less negative) the water potential.

Pure water has a water potential of what?

Pure water has a water potential of 0

63

Phospholipids are similar to lipids except that what?

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule

 

64

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Fatty acid molecules do what to water?

Fatty acid molecules repel water

65

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Fatty acid molecules repel water and so are what?

Fatty acid molecules:

1. Repel water

2. So are hydrophobic

66

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules do what to water?

Whereas fatty acid molecules:

1. Repel water

2. So are hydrophobic

,phosphate molecules attract water

67

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are what?

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules:

1. Attract water

2. So are hydrophilic

68

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.

A phospholipid is therefore made up of what?

A phospholipid is therefore made up of 2 parts, a:

1. Hydrophilic 'head'

2. Hydrophobic 'tail'

 

69

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.

A phospholipid is therefore made up of 2 parts, a hydrophilic 'head,' which does what, and a hydrophobic 'tail?'

A phospholipid is therefore made up of 2 parts, a:

1. Hydrophilic 'head,' which interacts with water (is attracted to it), but not with fat

2. Hydrophobic 'tail'

70

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.

A phospholipid is therefore made up of 2 parts, a hydrophilic 'head,' which interacts with water (is attracted to it), but not with fat, and a hydrophobic 'tail,' which does what?

A phospholipid is therefore made up of 2 parts, a:

1. Hydrophilic 'head,' which interacts with water (is attracted to it), but not with fat

2. Hydrophobic 'tail,' which orients itself away from water, but mixes readily with fat

71

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.

A phospholipid is therefore made up of 2 parts, a hydrophilic 'head,' which interacts with water (is attracted to it), but not with fat, and a hydrophobic 'tail,' which orients itself away from water, but mixes readily with fat.

Molecules that have 2 ends (poles) that behave differently in this way are said to be what?

Molecules that have 2 ends (poles) that behave differently in this way are said to be polar

72

Phospholipids are similar to lipids except that one of the fatty acid molecules is replaced by a phosphate molecule.

Whereas fatty acid molecules repel water and so are hydrophobic, phosphate molecules attract water and so are hydrophilic.

A phospholipid is therefore made up of 2 parts, a hydrophilic 'head,' which interacts with water (is attracted to it), but not with fat, and a hydrophobic 'tail,' which orients itself away from water, but mixes readily with fat.

Molecules that have 2 ends (poles) that behave differently in this way are said to be polar. This means that when these polar phospholipid molecules are placed in water they do what?

This means that when these polar phospholipid molecules are placed in water they position themselves so that the:

1. Hydrophilic heads are as close to the water as possible

2. Hydrophobic tails are as far away from the water as possible

73

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic what head and a hydrophobic tail of what?

Phospholipids are polar molecules, having a:

1. Hydrophilic phosphate head

2. Hydrophobic tail of 2 fatty acids

74

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules do what?

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes

75

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes.

As a result, what happens?

As a result, a hydrophobic barrier is formed between the:

1. Inside

2. Outside

of a cell

76

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes.

As a result, a hydrophobic barrier is formed between the inside and outside of a cell.

2. The hydrophilic phosphate 'heads' of phospholipid molecules help to do what?

The hydrophilic phosphate 'heads' of phospholipid molecules help to hold at the surface of the cell-surface membrane

77

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes.

As a result, a hydrophobic barrier is formed between the inside and outside of a cell. 2.

The hydrophilic phosphate 'heads' of phospholipid molecules help to hold at the surface of the cell-surface membrane.

3. The phospholipid structure allows phospholipids to form what?

The phospholipid structure allows phospholipids to form glycolipids

78

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes.

As a result, a hydrophobic barrier is formed between the inside and outside of a cell. 2.

The hydrophilic phosphate 'heads' of phospholipid molecules help to hold at the surface of the cell-surface membrane.

3. The phospholipid structure allows phospholipids to form glycolipids by doing what?

The phospholipid structure allows phospholipids to form glycolipids by combining with carbohydrates within the cell-surface membrane

79

The structure of phospholipids related to their properties:

1. Phospholipids are polar molecules, having a hydrophilic phosphate head and a hydrophobic tail of 2 fatty acids.

This means that in an aqueous environment, phospholipid molecules form a bilayer within cell-surface membranes.

As a result, a hydrophobic barrier is formed between the inside and outside of a cell.

2. The hydrophilic phosphate 'heads' of phospholipid molecules help to hold at the surface of the cell-surface membrane.

3. The phospholipid structure allows phospholipids to form glycolipids by combining with carbohydrates within the cell-surface membrane.

These glycolipids are important in what?

These glycolipids are important in cell recognition

80

The test for lipids is known as what?

The test for lipids is known as the emulsion test

81

The test for lipids is known as the emulsion test and is carried out as you:

Take a what?

Take a:

1. Completely dry

2. Grease-free

test tube

 

82

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add what to what?

 

Add 5cm³ of ethanol to 2cm³ of the sample being tested

 

83

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add 5cm³ of ethanol to 2cm³ of the sample being tested.

Shake the tube how to do what?

 

Shake the tube thoroughly to dissolve any lipid in the sample

 

84

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add 5cm³ of ethanol to 2cm³ of the sample being tested.

Shake the tube thoroughly to dissolve any lipid in the sample.

Add what and do what?

 

1. Add 5cm³ of water

2. Shake gently

 

85

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add 5cm³ of ethanol to 2cm³ of the sample being tested.

Shake the tube thoroughly to dissolve any lipid in the sample.

Add 5cm³ of water and shake gently.

What indicates the presence of a lipid?

A cloudy-white colour indicates the presence of a lipid

86

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add 5cm³ of ethanol to 2cm³ of the sample being tested.

Shake the tube thoroughly to dissolve any lipid in the sample.

Add 5cm³ of water and shake gently.

A cloudy-white colour indicates the presence of a lipid.

As a control, do what?

As a control, repeat the procedures using water instead of the sample

87

The test for lipids is known as the emulsion test and is carried out as you:

Take a completely dry and grease-free test tube.

Add 5cm³ of ethanol to 2cm³ of the sample being tested.

Shake the tube thoroughly to dissolve any lipid in the sample.

Add 5cm³ of water and shake gently.

A cloudy-white colour indicates the presence of a lipid.

As a control, repeat the procedures using water instead of the sample.

The final solution should do what?

The final solution should remain clear

88

The test for lipids is known as the emulsion test.

A cloudy-white colour indicates the presence of a lipid.

The cloudy colour is due to what?

The cloudy colour is due to any lipid in the sample being finely dispersed in the water to form an emulsion

89

The test for lipids is known as the emulsion test.

A cloudy-white colour indicates the presence of a lipid.

The cloudy colour is due to any lipid in the sample being finely dispersed in the water to form an emulsion.

Light passing through this emulsion is what?

Light passing through this emulsion is refracted

90

The test for lipids is known as the emulsion test.

A cloudy-white colour indicates the presence of a lipid.

The cloudy colour is due to any lipid in the sample being finely dispersed in the water to form an emulsion.

Light passing through this emulsion is refracted as it does what?

Light passing through this emulsion is refracted as it passes from:

1. Oil droplets

to

2. Water droplets

91

The test for lipids is known as the emulsion test.

A cloudy-white colour indicates the presence of a lipid.

The cloudy colour is due to any lipid in the sample being finely dispersed in the water to form an emulsion.

Light passing through this emulsion is refracted as it passes from oil droplets to water droplets, making the emulsion appear what?

Light passing through this emulsion is refracted as it passes from oil droplets to water droplets, making the emulsion appear cloudy

92

An amphipathic molecule

An amphipathic molecule is a molecule that has both:

1. Polar

2. Non-polar

regions

93

Phospholipids are what molecules?

Phospholipids are amphipathic molecules

94

Phospholipids are amphipathic molecules.

They have a what head?

Phospholipids have a hydrophilic head

95

Phospholipids are amphipathic molecules.

They have a hydrophilic head made up of what?

Phospholipids have a hydrophilic head made up of:

1. Glycerol

2. Phosphate

96

Phospholipids are amphipathic molecules.

They have a hydrophilic head made up of glycerol and phosphate and a what tail?

Phospholipids have a:

1. Hydrophilic head made up of glycerol and phosphate

2. Hydrophobic tail

97

Phospholipids are amphipathic molecules.

They have a hydrophilic head made up of glycerol and phosphate and a hydrophobic tail made up of what?

Phospholipids have a:

1. Hydrophilic head made up of glycerol and phosphate

2. Hydrophobic tail made up of 2 fatty acids

98

What does a mixed saturated and unsaturated lipid look like?

99

What is the phospholipid symbol?