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Flashcards in Lipids Deck (16)
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What are lipids?

- a group of substances that are soluble in alcohol rather than in water


What is a macromolecule?

- very large organic molecule
- complex molecules with relatively large molecular mass


What is a triglyceride?

1 molecule of glycerol attached to 3 fatty acids via ester bonds


How are ester bonds formed?

in a condensation reaction where water is released


What is esterification?

it is another name of a process in which triglycerides are formed


Structure of triglyceride

look at notes


What are saturated fatty acids?

- no double bonds between carbon atoms so a fatty acid is saturated with hydrogen


What are unsaturated fatty acids?

- has a double bonds so fewer hydrogen atoms can be bonded to the molecule
- double bonds cause kinks in the chain


Triglyceride properties/function

- mainly used as energy storage molecules
- good for storage as long hydrocarbon tails of fatty acids have lots of chemical energy so lots of energy can be released when they are broken down
- insoluble so doesn't cause water to enter cells by osmosis which would make them swell. They bundle together forming insoluble droplets as hydrophobic tails face inwards shielding themselves from water with their glycerol heads


Why do storage molecules need to be insoluble?

- otherwise they would dissolve and release whatever they were holding whenever they come in contact with water


Phospholipid structure

look in notes


What is a phospholipid?

1 molecule of glycerol with 2 fatty acids and 1 phosphate groups


Phospholipid properties/function

- found in cell membranes
- makes a phospholipid bilayer where hydrophilic heads face out to water on both sides of membrane and the hydrophobic tails face inwards
- centre of bilayer is hydrophobic so water-soluble substances cant easily pass through hence membrane acts as a barrier to these substances


What is cholesterol?

- a hydrocarbon ring structure attached to a hydrocarbon tail.
- ring structure has a polar hydroxyl (OH) group attached to it


cholesterol structure

look in notes


cholesterol properties/function

- helps strengthen membranes in eukaryotic cells by interacting with phospholipid bilayer
- small size and flattened shape so allows it to fit between the phospholipid molecules in membrane
- bind to hydrophobic tails of phospholipids causing them to pack more closely together. it helps to make membrane less fluid and more rigid.