Trigylcerides

Question 1

Triglycerides

Answer 1

-Most common lipids:
>Fats are solids at room temp
>Oils are liquids at room temp
-Less dense than water (float)
-Non polar - no uneven distribution of charges
-Hydrophobic - don't dissolve in water
-Dissolve in organic solvent eg alcohol
-Contains the elements: Carbon, Hydrogen and Oxygen

Question 2

Structure of triglycerides

Answer 2

3 Fatty Acids joined to a glycerol

Question 3

General Fatty Acid Structure

Answer 3

Fatty acids vary in two main ways:

• The length of the carbon chain (usually 15-17 C long)
• The type of bonds between the carbon atoms - single or double bonds

Question 4

Saturated Fatty Acid

Answer 4

• Contain no C=C double bonds
• Generally are solids or semisolids at room temp
• Animal fat is a major source

Question 5

Monounsaturated/Polyunsaturated

Answer 5

• Contain one or more C=C double bonds
• Generally are liquids at room temp
• Vegetable oils are major source

Question 6

General Formulas

Answer 6

Saturated Fatty Acid - CnH2n+1COOH

Unsaturated Fatty Acid - CnH2n-1COOH

Question 7

Formation of a triglyceride

Answer 7

The fatty acids join to glycerol a condensation reaction forming a triglyceride and 3 moles of water

Question 8

Digestion of Lipids

Answer 8

• Hydrolysis Reaction
• Add Water
• Enzyme=Lipase

Question 9

Lipid Function

Answer 9

1) Heat Insulation - fat conducts heat very slowly so having a layer under the skin keeps metabolic heat in
2) Energy Storage - lipids are non-polar and so are insoluble in water. They also yield more energy than the same mass of carbohydrate . They are an energy store in seeds and animals
3) Waterproofing - waxy cuticles are useful, for example, to prevent excess evaporation from the surface of a leaf
4) Buoyancy - as lipids float on water, they can have a role in maintaining buoyancy in organisms
5) Protection - against knocks for delicate internal organs such as kidneys
6) Production of water - fatty acids produce a lot of water when they are oxidised during respiration

Question 10

Phospholipids

Answer 10

• Lipids with a phosphate group
• Glycerol joins with phosphoric acid (H3PO40 and 2 fatty acids
• It is a polar molecule

Question 11

Solubility of Phospholipids

Answer 11

Phosphate head carries an electric charge

• Head is soluble in water - Hydrophilic
• Tail is insoluble in water - Hydrophobic

Question 12

Micelle Formation

Answer 12

Forms when phospholipids are placed in water

Question 13

Phospholipids function

Answer 13

Form bilayers and are the main component of cell membranes and organelle memebranes