lipids

Question 1

explain lipids

Answer 1

• they contain carbon, hydrogen and oxygen
• they are non polar
• they dissolve non polar substances
• at room temperature, fats are solid and oils are liquids

Question 2

what are the functions of lipids

Answer 2

• energy storage and source
• protection of delicate organs from physical damage
• oxidation of triglycerides produces metabolic water
• membranes = phospholipids are an important part in biological membranes
• waterproofing
• insulation
• hormones

Question 3

what are saturated fatty acids

Answer 3

• all the carbon atoms are joined by a single bond in the hydrocarbon chain
• they form straight chains
• have a high melting point
• tend to be found in animals (fats)

Question 4

what are unsaturated fatty acids

Answer 4

• the hydrocarbon chain contains double bonds between the carbons
• form bent chains
• have a low melting point
• if they have more than one double bond they are called poly-unsaturated
• tend to be found in plants (oils)

Question 5

what are triglycerides

Answer 5

• they are commonly called fats or oils
• they contain three fatty acid chains and one glycerol
• joined by a condensation reaction and an ester bond is formed

Question 6

what are phospholipids

Answer 6

• they are similar to triglycerides but contain two fatty acid chains and a phosphate group
• they have hydrophilic heads and hydrophobic tails
• when mixed with water they form droplet spheres, this is called micelle
• they also form phospholipid bilayers

Question 7

what is cholesterol

Answer 7

• its found in all biological membranes
• helps to regulate the fluidity of the membrane
• 4 carbon based ring structure

Question 8

what are lipoproteins

Answer 8

• soluble proteins combine with and transport fat or other lipids in the blood plasma
• fats on their own are insoluble so cannot be transported in the blood plasma

Question 9

what is LDL

Answer 9

• low density lipoproteins
• a diet high in saturated fats increases the livers production of LDL
• an excess of these fats could lead to atheroma

Question 10

what is HDL

Answer 10

• high density lipoproteins
• a diet high in unsaturated fats increases the livers production of HDL
• this can round up any excess LDL and return it to the liver to reduce the chances of an atheroma