Lipids Flashcards
State the elements present in lipids (and the additional element needed to make phospholipids).
carbon, oxygen, hydrogen,
phosphor
Define the term “macromolecule”.
a macromolecules are complex molecules with a relatively large molecular mass. polymers are a group of macromolecules
State the 3 categories of lipids (or lipid derived molecules)
Triglycerides, phospholipids and steroids (cholesteral is a type of steroid)
Draw a labelled diagram showing the basic structure of a triglyceride.
fatty acid tails attached to one molecule of glycerol. they are synthesised by the formation of an ester bond. between each fatty acid and the glycerol
State the components of a triglyceride.
3 fatty acid tails and a glycerol head
draw a diagram of a triglyceride with elements
draw it on paper
State the difference between saturated, monounsaturated and polyunsaturated fatty acids/triglycerides.
Saturated fatty acids- don’t have any double bonds between their carbon atoms in their hydrocarbon tails. this means they can pack together as they are straight and are Solid at RT
Monounsaturated fatty acids/ polyunsaturated fatty acids- have at least one double bond between carbon atoms which causes the chain to kink. this means they can’t pack together and are normally liquid at RT. Monounsaturated fatty acids only have one double bond. Poly have two or more double bonds.
Explain why saturated triglycerides tend to be solid (fats) at room temperature whereas unsaturated triglycerides tend to be liquid (oils).
Saturated triglycerides don’t have kinks so can pack together tightly so are solid
unsaturated triglycerides have kinks so can’t pack together tightly making them Liquid at RT
Describe and explain how the melting point of a triglyceride would correlate with the length of the fatty acids it contained
Long chain fatty acids have a higher melting point as they have a longer hydrocarbon tail, so they can absorb more energy so more energy is required to break the bonds and melt it.
State the difference between the triglycerides found in non-fish animals and those in plants and fish.
Plants have unsaturated triglycerides and animals have saturated triglycerides. don’t know about fish
Draw a labelled diagram showing the basic structure of a phospholipid.
They have the same structure as a triglyceride apart from one of the fatty acid tails is replaced by a phosphate group which is on the opposite side of the glycerol.
State the property that each end of the phospholipid has.
the phosphate group is charged and is hydrophilic - attracts water molecules
Fatty acid tails are non- polar and hydrophobic
Draw a diagram to show how a triglyceride is formed and broken down.
Ester bonds are forms by a condensation reactions where a water molecule is released- esterification
Hydroxyl groups from the fatty acid tails and the glycerol interact to produce 3 water molecules and 3 ester bonds.
When ester bonds are broken in a hydrolysis reaction where a water molecule is used up, the triglyceride breaks down into fatty acids and a glycerol.
State the products of digestion of a triglyceride (include partial digestion) and state what would happen to the pH of the solution (and why).
Products of digestion- free fatty acids and monoglycerides
the PH of the solution would go down- more acidic- because you have free fatty acids which are acids in the solution
Describe the structure of sterols/cholesterol.
They are complex alcohol molecules based on a carbon ring structure attached to a hydrocarbon tail. The ring has a polar hydroxyl group attached to it which is hydrophillic and the rest is non-polar and hydrophobic.
