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1.2 (biological molecules) Flashcards

lipids

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1
Q

lipids are macromolcules which contain what atoms

A
  • carbon
  • hydrogen
  • oxygen
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2
Q

unlike carbohydrates lipids contain a lower proportion of

A

oxygen

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3
Q

the two groups of lipids are

A
  • triglycerides (the main component of fats and oils)
  • phospholipids
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4
Q

triglycerides are non polar and what molecules

A

hydrophobic

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5
Q

the monomers of triglycerides are

A
  • glycerol
  • fatty acids
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6
Q

glycerol is an alcohol meaning that it is an

A
  • it is an organic molecule
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7
Q

glycerol is an alcohol meaning that it is an organic molecule that contains

A

a hydroxyl group bonded to a carbon atom

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8
Q

what kind of chain do fatty acids have

A

hydrocarbon

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9
Q

fatty acids contain a what group at one end of a hydrocarbon chain

A

methyl

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10
Q

what are the two groups at either end of a lipid

A
  • methyl group CH3
  • carboxyl group COOH
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11
Q

the hydrocarbon chain of a lipid is known as what group

A

R group

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12
Q

the shorthand chemical formula for a fatty acid is

A

RCOOH

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13
Q

fatty acids can vary in what two ways

A
  • length of the hydrocarbon chain (R group)
  • the fatty acid chain (R group) may be saturated (mainly in animal fat) or unsaturated (mainly vegetable oils, although there are exceptions e.g. coconut and palm oil)
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14
Q

unsaturated fatty acids can be what two types of unsaturated

A

mono or poly-unsaturated

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15
Q

if H atoms are on the same side of the double bond in a fatty acid then it is a

A
  • cis-fatty acids
  • metabolised by enzymes
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16
Q

if H atoms are on opposite sides of the double bond in a fatty acid then it is a

A
  • trans-fatty acid and cannot form enzyme-substrate complexes
  • therefore not metabolised by enzymes
  • they are linked with coronary heart disease
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17
Q

what type of unsaturated fatty acid can be metabolised by enzymes

A

cis-fatty acids

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18
Q

what type of unsaturated fatty acid cannot be metabolised by enzymes

A

trans-fatty acids

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19
Q

trans-fatty acid cannot form

A
  • enzyme-substrate complexes
  • therefore not metabolised by enzymes
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20
Q

what type of unsaturated fatty acid is linked with coronary heart disease

A
  • trans-fatty acids
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21
Q

triglycerides are formed by

A

esterification

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22
Q

an ester bond forms when a what group on glycerol bonds with the what group of the fatty acid

A
  • hydroxyl (-OH)
  • carboxyl (-COOH)
  • (an ester bond forms when a hydroxyl (-OH) group on glycerol bonds with the carboxyl (-COOH) group of the fatty acid)
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23
Q

the formation of an ester bond is a what reaction

A

condensation

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24
Q

for each ester bond formed a what molecule is released

A

water

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25
Q

three fatty acids join to one glycerol molecule to form a triglyceride, therefore for one triglyceride to form, how many water molecules are released

A

three

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26
Q

what are the four main functions of a triglyeride

A
  • energy storage
  • insulation
  • buoyancy
  • protection
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27
Q

as triglycerides are hydrophobic they do not cause

A
  • osmotic water uptake in cells
  • so more can be stored
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28
Q

plants store triglycerides in the form of what where

A
  • oils
  • in their seeds and fruits
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29
Q

if triglycerides oils are extracted from seeds and fruits these are generally liquid at room temperature due to the presence of

A
  • double bonds
  • which add kinks to the fatty acid chains altering their properties
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30
Q

mammals store triglycerides as what where

A
  • oil droplets
  • in adipose tissue to help them survive when food is scarce (e.g. hibernating bears)
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31
Q

the oxidation of the carbon-hydrogen bonds releases large numbers of what during what

A
  • water molecules (metabolic water) - during cellular respiration
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32
Q

desert animals retain what water if there is no liquid water to drink

A

metabolic water

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33
Q

bird and reptile embryos in their shells also use what water

A

metabolic water

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34
Q

triglycerides are part of the composition of the what that surrounds nerve fibres

A

myelin sheath

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35
Q

triglycerides are part of the composition of the myelin sheath that surrounds nerve fibres, this provides insulation which increases

A

the speed of transmission of nerve impulses

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36
Q

triglycerides compose part of the what tissue layer below the skin which acts as insulation against heat loss (eg. blubber of whales)

A

adipose

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37
Q

the low density of fat tissue increases the ability of animals to

A

float more easily

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38
Q

the adipose tissue in mammals contains stored triglycerides and this tissue helps protect organs from

A

the risk of damage

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39
Q

phospholipids are a type of lipid, therefore they are formed from the monomer what and what

A

glycerol and fatty acids

40
Q

in a phospholipid how many fatty acids are bonded to a glycerol molecule

A

two

41
Q

unlike triglycerides, there are only two fatty acids bonded to a glycerol molecule in a phospholipid as one has been replaced by a

A

phosphate ion (group)

42
Q

as the phosphate of a phospholipid is what it is what in water

A
  • polar
  • soluble in water (hydrophilic)
43
Q

the fatty acid ‘tails’ of a phospholipid are what it is what in water

A
  • non-polar
  • insoluble in water (hydrophobic)
44
Q

phospholipid diagram

A
45
Q

phospholipids are the major components of cell

A

surface membranes

46
Q

phospholipids have both hydrophobic and hydrophilic parts and so are

A

amphipathic

47
Q

as a result of having hydrophobic and hydrophilic parts phospholipid molecules form what in water

A

monolayers or bilayers in water

48
Q

role of phospholipids (5)

A
  • the main component (building block) of cell membranes
  • due to the presence of hydrophobic fatty acid tails, a hydrophobic core is created when a phospholipid bilayer forms: this acts as a barrier to water-soluble molecules
  • the hydrophilic phosphate heads form H-bonds with water allowing the cell membrane to be used to compartmentalise: this enables the cells to organise specific roles into organelles helping with efficiency
  • composition of phospholipids contributes to the fluidity of the cell membrane: if there are mainly saturated fatty acid tails then the membrane will be less fluid; if there are mainly unsaturated fatty acid tails then the membrane will be more fluid
  • phospholipids control membrane protein orientation: weak hydrophobic interactions between the phospholipids and membrane proteins hold the proteins within the membrane but still allow movement within the layer
49
Q

phospholipids are the main component (building block) of

A

cell membranes

50
Q

due to the presence of hydrophobic fatty acid tails, a

A
  • hydrophobic core is created
  • when a phospholipid bilayer forms
51
Q

the hydrophobic core created when a phospholipid bilayer forms acts as a what to what

A
  • barrier
  • to water-soluble molecules
52
Q

the hydrophilic phosphate heads form what bonds with water

A

hydrogen

53
Q

the hydrophilic phosphate heads form H-bonds with water allowing the cell membrane to be used to

A

compartmentalise

54
Q

the hydrophilic phosphate heads form H-bonds with water allowing the cell membrane to be used to compartmentalise, this enables the cells to organise what into organelles helping with what

A
  • specific roles into organelles
  • helping with efficiency
  • (this enables the cells to organise specific roles into organelles helping with efficiency)
55
Q

composition of phospholipids contributes to the what of the cell membrane

A

fluidity

56
Q

if there are mainly saturated fatty acid tails then the membrane will be

A

less fluid

57
Q

if there are mainly unsaturated fatty acid tails then the membrane will be

A

more fluid

58
Q

phospholipids control membrane protein

A

orientation

59
Q

phospholipids control membrane protein orientation, as weak hydrophobic interactions between the phospholipids and membrane proteins do what

A
  • hold the proteins within the membrane - but still allow movement within the layer
60
Q

what hydrophobic interactions between the phospholipids and membrane proteins hold the proteins within the membrane but still allow movement within the layer

A

weak

61
Q

number of fatty acid tails in a phospholipid

A

2

62
Q

number of fatty acid tails in a triglyceride

A

3

63
Q

what part of a phospholipid is polar

A

phosphate head

64
Q

what part of a phospholipid is non polar

A

fatty acid tails

65
Q

is a triglyceride polar or non polar

A

non polar

66
Q

number of water molecules released during the formation of a phospholipid and triglyceride

A

3

67
Q

overall function of a phospholipid is

A

to be a cell membrane component

68
Q

overall function of a tricglyceride is

A

for energy storage

69
Q

triglycerides are a form of

A

lipid

70
Q

triglycerides are made up of

A
  • one molecule of glycerol
  • with three fatty acids attached to it
71
Q

fatty acids in a triglyceride have long what tails

A

hydrocarbon

72
Q

fatty acids occur in what two forms

A
  • saturated
  • unsaturated
73
Q

the difference between these saturated and unsaturated fatty acid types is found in their

A

hydrocarbon tails

74
Q

in saturated fatty acids, the bonds between the carbon atoms in the hydrocarbon tail are all

A

single bonds

75
Q

the fatty acid is said to be what with hydrogen

A
  • saturated
  • this means that each carbon atom in the hydrocarbon tail (except for the final carbon atom) is bonded to two hydrogen atoms
76
Q

an example of a saturated fatty acid diagram

A
77
Q

in unsaturated fatty acids there is at least one

A

carbon-carbon double bond

78
Q

these double bonds cause the hydrocarbon tail of unsaturated fatty acids to

A
  • kink
  • not as straight as saturated fatty acids
79
Q

the fatty acid is said to be

A

unsaturated

80
Q

the fatty acid is said to be ‘unsaturated’ because the hydrocarbon tail does not contain the maximum number of

A
  • hydrogen atoms possible
  • this is because each carbon atom in a carbon-carbon double bond can only bond to one hydrogen atom (instead of two)
81
Q

an example of an unsaturated fatty acid diagram

A
82
Q

triglycerides are mainly used as

A

energy storage molecules

83
Q

triglycerides are mainly used as energy storage molecules, this is because the long hydrocarbon tails of the fatty acids in triglycerides contain large amounts of

A
  • chemical energy
  • which can be released when the fatty acids are broken down
84
Q

triglycerides are also suitable as energy storage molecules because they are what so

A
  • insoluble
  • dont affect the water potential inside the cell
85
Q

inside cells, triglycerides form

A
  • insoluble droplets
  • hydrophobic (water-repelling) fatty acids on the inside
  • glycerol molecules on the outside
86
Q

triglyceride insoluble droplets inside cells diagram

A

triglycerides are suitable as energy storage molecules as they form insoluble droplets inside cells

87
Q

phospholipids are another kind of

A

lipid

88
Q

in phospholipids, one of the three fatty acid molecules attached to glycerol is replaced by a

A

phosphate group

89
Q

this phosphate group is in a phospholipid is

A

hydrophilic

90
Q

this phosphate group is hydrophilic (water-loving), whereas the two fatty acids are

A

hydrophobic (like in triglycerides)

91
Q

in phosholipids the hydrophilic phosphate head and hyprophpbic fatty acid tails makes phospholipids suitable for making up the

A
  • bilayer of cell membranes
  • with the fatty acids facing inwards and the phosphate groups facing outwards
92
Q

this is also useful as it means the centre of the phospholipid bilayer is

A

hydrophobic

93
Q

this is also useful as it means the centre of the phospholipid bilayer is hydrophobic, meaning

A

water-soluble substances cannot easily pass through

94
Q

this allows the cell membrane of a phospholipid to act as a

A
  • barrier
  • controlling what substances enter and leave the cell
95
Q

phospholipids bilayer diagram

A

phospholipids are suitable for making up cell membranes as they form a bilayer

as biology (sme) (8 decks)

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