1.5: Lipids Flashcards
1
Q
Lipids are a varied group of substances that share the following characteristics:
- They contain what?
A
Lipids contain:
- Carbon
- Hydrogen
- Oxygen
2
Q
Lipids are a varied group of substances that share the following characteristics:
- Lipids contain carbon, hydrogen and oxygen.
- The proportion of oxygen to carbon and hydrogen is what?
A
The proportion of oxygen to:
- Carbon
- Hydrogen
is smaller than in carbohydrates
3
Q
Lipids are a varied group of substances that share the following characteristics:
- Lipids contain carbon, hydrogen and oxygen.
- The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.
- They are what in water?
A
Lipids are insoluble in water
4
Q
Lipids are a varied group of substances that share the following characteristics:
- Lipids contain carbon, hydrogen and oxygen.
- The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.
- Lipids are insoluble in water.
- They are soluble in what?
A
Lipids are soluble in organic solvents
5
Q
Lipids are a varied group of substances that share the following characteristics:
- Lipids contain carbon, hydrogen and oxygen.
- The proportion of oxygen to carbon and hydrogen is smaller than in carbohydrates.
- Lipids are insoluble in water.
- They are soluble in organic solvents, such as what?
A
Lipids are soluble in organic solvents, such as:
- Alcohols
- Acetone
6
Q
The main groups of lipids are what?
A
The main groups of lipids are:
- Triglycerides
- Phospholipids
7
Q
The main groups of lipids are triglycerides, which are what, and phospholipids?
A
The main groups of lipids are triglycerides:
- Fats
- Oils
,and phospholipids
8
Q
Triglyceride
A
A triglyceride is an individual lipid molecule made up of:
- A glycerol molecule
- 3 fatty acids
9
Q
Fats are generally made of what fatty acids?
A
Fats are generally made of saturated fatty acids
10
Q
Fats are generally made of saturated fatty acids, while oils are made of what?
A
- Fats are generally made of saturated fatty acids
,while
- Oils are made of unsaturated fatty acids
11
Q
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?
A
- Fats are solid at room temperature
,whereas
- Oils are liquid
12
Q
Lipids have many roles.
One role of lipids is in cell what?
A
One role of lipids is in cell membranes
13
Q
Lipids have many roles.
One role of lipids is in cell membranes, as what?
A
One role of lipids is in cell membranes, as:
- Cell-surface membranes
- Membranes around organelles
14
Q
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?
A
Phospholipids contribute to the flexibility of cell membranes
15
Q
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?
A
Phospholipids contribute to the:
- Flexibility of cell membranes
- Transfer of lipid-soluble substances across them
16
Q
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:
- Lipids are a source of what?
A
Lipids are a source of energy
17
Q
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:
- Lipids are a source of energy.
When oxidised, what do lipids do?
A
When oxidised, lipids:
- Provide more than twice the energy as the same mass of carbohydrate
- Release valuable water
18
Q
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:
- 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.
- Lipids can be what?
A
Lipids can be waterproofing
19
Q
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:
- 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.
- Lipids can be waterproofing.
Lipids are insoluble in water and therefore useful in waterproofing.
Both plants and insects have what?
A
Both plants and insects have:
- Waxy
- Lipid
cuticles
20
Q
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:
- 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.
- 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?
A
Both:
- Plants
- Insects
have waxy, lipid cuticles that conserve water
21
Q
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:
- 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.
- 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?
A
Both:
- Plants
- Insects
have waxy, lipid cuticles that conserve water, while mammals produce an oily secretion from the sebaceous glands in the skin
22
Q
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:
- 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.
- 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.
- Lipids can be used for i?
A
Lipids can be used for insulation
23
Q
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:
- 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.
- 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.
- Lipids can be used for insulation.
Fats are slow conductors of what?
A
Fats are slow conductors of heat
24
Q
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:
- 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.
- 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.
- Lipids can be used for insulation.
Fats are slow conductors of heat and when stored beneath the body surface help to do what?
A
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?
