lipids Flashcards

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1
Q

how is a triglyceride formed

A

by a condensation reaction of one molecule of glycerol (alcohol) and 3 molecules of fatty acids

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2
Q

how many condensation reactions are required to form a triglyceride

A

3 condensation reactions so 3 water molecules are removed

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3
Q

how many bonds are found in each triglyceride molecule

A

3 ester bonds

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4
Q

how is water molecule removed

A

in a condensation reaction, H is removed from glycerol and OH is removed from fatty acid

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5
Q

why is 1 triglyceride molecule not a polymer

A

its not made of the same monomers

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6
Q

where are triglycerides usually found

A

in food (storage molecules)

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7
Q

what do phospholipids do

A

form a cell membrane around the cell

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8
Q

give other functions of lipids

A

-conduct heat slowly (so are good thermal and electric insulators)
-stored around delicate organs like liver and kidney
-similar to waxes however it contains alcohol

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9
Q

compare the proportion of oxygen in lipids and carbohydrates

A

much less in lipids (C:H2:O)

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10
Q

how are fatty acids an R group and give the 2 types

A

-because numbers of hydrogens and carbons can differ
-saturated and unsaturated

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11
Q

what is a saturated fatty acid

A

-when the hydrocarbon chain has only single bonds between carbons, bonded to maximum numbers of hydrogen
-most likely to be solid at room temp because chains are packed together

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12
Q

what is an unsaturated fatty acid

A

-when the hydrocarbon chain consists of at least one double bond between carbons, not holding maximum numbers of hydrogen possible
-most likely to be liquid at room temp

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13
Q

why are unsaturated fatty acids likely to be liquid at room temp

A

sometimes the double bond causes a bend/kink that prevents the fatty acids from packing tightly, keeping them liquid.

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14
Q

give the properties and their uses of a triglyceride

A

-ENERGY STORE = due to large ratio of energy-storing carbon-hydrogen bonds to number of carbons, a lot of energy is stored in molecule
-due to high ratio of hydrogen to oxygen atoms triglycerides act as a METABOLIC WATER SOURCE, so they can release water if they are oxidised, essential for animals in dry areas like camels
-triglycerides don’t affect water potential and osmosis because they are large and HYDROPHOBIC making them insoluble in water
-lipids have a relatively LOW MASS so a lot can be stored without increasing the mass if organism and without preventing restriction of movement

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15
Q

how is a phospholipid formed

A

by 2 condensation reactions resulting in 2 ester bonds

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16
Q

what is a phospholipid made up of

A

1 glycerol 2 fatty acids chain and a phosphate group (attached to the glycerol)

17
Q

give the properties of phospholipids

A

POLAR-the hydrophilic ‘head’ (phosphate group) can attract water as it is charged , so it’ll repel other fats
NON-POLAR-the fatty acid chain is known as the hydrophobic ‘tail’ and it repels water bc it has no charge but it will mix with other fats

18
Q

because of the properties of phospholipids, how will they arrange themselves in water

A

-they will arrange themselves in 2 layers called a bilayer
-hydrophobic fatty acids tails will face each other away from water
-hydrophilic heads are exposed to water

19
Q

what does a phospholipid bilayer form

A

a membrane structure which makes up the plasma membrane around cells / cell membrane