lipids

Question 1

Types of lipids

Answer 1

• triglycerides
• phospholipids

Question 2

How are triglycerides formed?

Answer 2

• They are formed via a condensation reaction between one molecule of glycerol and 3 molecules of fatty acids.
• This forms an (RCOOH) and forms an ester bond.

Question 3

Draw a triglyceride and label it.

Answer 3

answer

Question 4

What are saturated fatty acids?

Answer 4

It is when the hydrocarbon only has single bonds between carbons.

Question 5

What are unsaturated fatty acids?

Answer 5

It is when the hydrocarbon consists of at least one double bond between carbons.

Question 6

What are some properties of triglycerides?

Answer 6

• Energy storage
• Metabolic water source
• Do not affect water potential
• Low mass

Question 7

Triglycerides have the property energy storage. What does this mean?

Answer 7

• Due to the large ratio of energy storing carbon-hydrogen bonds compared to the number of carbon atoms, a lot of energy is stored in the molecule.

Question 8

Triglycerides are a metabolic water source. What does this mean?

Answer 8

• Due to the high ratio of hydrogen to oxygen atoms, they act as a metabolic water source. Triglycerides can release water if they are oxidised.
• This is essential for animals in the desert - such as camels.

Question 9

Triglycerides do not affect water potential. Why is this so?

Answer 9

As they are large and hydrophobic - making them insoluble in water.

Question 10

Triglycerides have a low mass. Why is this beneficial?

Answer 10

• A lot can be stored without increasing the mass and preventing movement.

Question 11

Describe the emulsion test.

Answer 11

1. Dissolve the sample in ethanol.
2. Add distilled water.
3. If a white emulsion appears - there is a lipid.

Question 12

What do phospholipids consist of?

Answer 12

• They are made of a glycerol molecule, two fatty acid chains and a phosphate group.
• The two fatty acids also bond to the glycerol via two condensation reactions.
• This results in ester bonds.

Question 13

Draw and label a diagram of a phospholipid.

Answer 13

answer

Question 14

What are the properties of phospholipids?

Answer 14

• hydrophillic head
• hydrophobic tail
• phospholipid bilayer

Question 15

What does having a hydrophillic head mean?

Answer 15

• Attracts with water - charged.
• Due to the phosphate being charged, it repels other fats.

Question 16

What does having a hydrophobic tail mean?

Answer 16

• It is not charged, it repels water but it will mix with fats.

Question 17

What does being apart of the phospholipid bilayer mean?

Answer 17

• Have two charged regions - polar.
• In water, they are positioned so that the heads are exposed to water and the tails are not.
• This forms a phospholipid bilayer - membrane structure.
• It makes up the plasma membrane around cells.