Triglycerides And Phospholipids

Question 1

Triglycerides structure

Answer 1

1 glycerol, 3 fatty acids, 3 condensation reactions, 3 ester bonds

Question 2

Phospholipids structure

Answer 2

1 glycerol, 2 fatty acids, I phosphate group, 2 condensation reactions, 2 ester bonds

Question 3

Saturated fatty acids

Answer 3

Only single bonds between carbons

Question 4

Unsaturated fatty acid

Answer 4

At least one double bond between carbons

Question 5

Properties of triglycerides

Answer 5

• Energy storage- large ratio of carbon - hydrogen bonds which hold a lot of energy compared to number of carbon atoms
• High ratio of hydrogen to oxygen atoms - act as a metabolic water source - release water if they are oxidised
• Do not affect water potentials and osmosis because they are large and hydrophobic making them insoluble.
• Low in mass-can be stored without increasing mass and preventing movement
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Question 6

Emulsion test for lipids

Answer 6

-Dissolve sample in ethanol
- add distilled water
- if a white emulsion appears there is a lipid 

Question 7

Properties of phospholipids

Answer 7

• Hydrophilic ‘ head’ can attract with water as it is charged
• Due to phosphate being charged, it repels other fats
• Hydrophobic tail, repels water but will mix with fats as it is not charged.

Question 8

The phospholipid bilayer

Answer 8

• two charged regions so are polar
• In water, heads exposed to water and tails are not
• forms of phospholipid bilayer membrane structure, makes up plasma membrane around cells