Lipids

Triglycerides, phospholipids, glycolipids and cholesterol are all examples of ...?
Lipids.
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Lipids contain large amounts of c_____ and h_______ and smaller amounts of o_____.
Lipids contain large amounts of CARBON and HYDROGEN and smaller amounts of OXYGEN.
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Why are lipids insoluble in water? What are they soluble in?
They are not polar so they do not attract water molecules. They do dissolve in alcohol.
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They are NOT polymers, what are they examples of?
They have different components bonded together, they are examples of macromolecules.
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What are triglycerides made up of?
Fatty acids and glycerol.
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There are many different types of fatty acids and most we can make in our bodies but some must be ingested 'complete'. What are these fatty acids called?
Essential fatty acids.
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How many carbon atoms does glycerol have?
3
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Glycerol is an alcohol, what does this mean?
It has free -OH groups (glycerol has three of these which is what makes a TRIglyceride)
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What do fatty acids have on one end?
A carboxyl group (-COOH).
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Fatty acids have a hydrocarbon tail made only of carbon and hydrogen atoms. It is what the carboxyl group is attached to. How many carbons long can this be?
Anything from 2-20 carbons long.
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The carboxyl group ionises into H+ and -COO-. This makes it an acid, why?
Because it can produce free H+ ions.
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A saturated fatty acid is one with no .........?
C=C bonds.
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If the fatty acid is unsaturated?
There is a double bond between two of the carbon atoms and less hydrogen atoms can be bonded to the molecule.
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What is the difference between a monounsaturated fatty acid and a polyunsaturated fatty acid?
Monounsaturated fatty acids have only one C=C bond and polyunsaturated have more than one.
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Having C=C bond(s) changes the shape of the hydrocarbon chain and gives it a kink where the double bond is. What does this mean for the properties of the fatty acid?
Because the molecules are pushed slightly apart it makes them more fluid and so more unsaturated fatty acids can decrease a melting point.
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A triglyceride is one glycerol molecule bonded to 3 fatty acids by a condensation reaction between what?
The -COOH group of the fatty acid and the -OH group of the glycerol.
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What is an ester bond?
The covalent bond formed with a triglyceride.
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Triglycerides can be broken down to release energy during respiration. How is this done and what does it make triglycerides a good source of?
The ester bonds are first hydrolysed then the glycerol and fatty acids broken down completely to CO2 and water. This makes triglycerides a good energy source.
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What produces more water, the respiration of lipids or sugar?
Lipids.
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Triglycerides are insoluble in water and they can be stored without affecting the water potential of a cell. What does this make them good for?
Energy storage.
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What else are triglycerides good for?
Insulation (adipose tissue is heat insulation and lipids in nerves cells act as electrical insulators); buoyancy (fat is less dense than water) and protection (fat around delicate organs)
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What is the difference between a phospholipid and a triglyceride?
They have the same structure except a phospolipid has a phosphate group instead of one of the fatty acids.
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The phosphate group of a phospholipid is slightly negative and so polar but the fatty acid tails are not polar, what does this mean?
The phosphate group, the 'head', is hydrophilic and the fatty acid tails are hydrophobic.
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What does amphipathic mean?
It has a hydrophilic and a hydrophobic part.
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How do amphipathic phospholipids behave in water?
They might form a layer on the surface with heads in and tails sticking out or the may for 'micelles' which are little balls with the heads outside and the tails tucked inside.
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Phospholipids form the bilayer that is the main part of cell membranes, how do they do this?
Two rows of phospholipids mirroring eachother with the tails in and the heads out on either side, exposed to the water.
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The membrane is selectively permeable, what does this mean?
Only small, non-polar molecules can move through it.
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What is cholesterol?
A small, hydrophobic lipid/steroid alcohol made of four carbon-based rings/ isoperene units.
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Because it is hydrophobic, cholesterol can sit in the hydrophobic part of the bilayer. What function does it serve there?
It regulates fluidity and stops it becoming to fluid or too stiff.
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Where is cholesterol mainly made in animals?
The liver.
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Testosterone, oestrogen and vitamin D are all what?
Steroid hormones made from cholesterol.
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Other cards in this set

Card 2

Front

Lipids contain large amounts of c_____ and h_______ and smaller amounts of o_____.

Back

Lipids contain large amounts of CARBON and HYDROGEN and smaller amounts of OXYGEN.

Card 3

Front

Why are lipids insoluble in water? What are they soluble in?

Back

Preview of the front of card 3

Card 4

Front

They are NOT polymers, what are they examples of?

Back

Preview of the front of card 4

Card 5

Front

What are triglycerides made up of?

Back

Preview of the front of card 5
View more cards

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