Lipids

Question 1

What elements are lipids made of?

Answer 1

Hydrogen
Carbon
Oxygen

Question 2

Lipids are hydrophobic. What does this mean ?

Answer 2

The molecule does not mix with water. The oil and water molecules repel each other

Question 3

What are the 3 types of lipids?

Answer 3

Phospholipids
Steroids
Triglycerides

Question 4

What is the E shaped molecule called?

Why is it called this?

Answer 4

Triglycerides

Triglycerides are made of three fatty acids attached to a glycerine backbone

Question 5

How many types of fatty acids are there?

Answer 5

70+

Question 6

What makes the different fatty acids actually different?

Answer 6

Different “R” groups/ variant “R” groups

Question 7

What is meant by a saturated Fatty acid?

Answer 7

Where all the carbons on the carbon chain are connected together by single bonds and have the highest number of hydrogens connected to each of these carbons.

Question 8

What is meant by an unsaturated hydrocarbon?

Answer 8

Where the hydrocarbon has a double bond between carbons in the hydrocarbon tails

Question 9

How does the double bond affect the shape of the chain and the state of the fat at room temp?

Answer 9

The hydrocarbon tail has a kink in it. At room temperature the fat is a liquid.

Question 10

What does monounsaturated mean?

Answer 10

There is only one double bond in the hydrocarbon tail

Question 11

What does polyunsaturated mean?

Answer 11

There are multiple double bonds in the hydrocarbon chain

Question 12

How do triglycerides form?

Answer 12

Through a condensation/ esterification reaction
This happens 3 times, 1 for each hydrocarbon tail.
A water molecule is removed every time one hydrocarbon is attached so in total 3 water molecules are removed

Question 13

What bonds are formed during triglyceride formation?

Answer 13

Ester bonds

Question 14

What has a higher boiling point unsaturated or saturated triglycerides?

Answer 14

Saturated triglycerides

Question 15

Where do saturated triglycerides derived from ?

Answer 15

Animals

Question 16

Where are unsaturated triglycerides derived from?

Answer 16

Plants

Question 17

Why are triglycerides a great source of energy?

Answer 17

They contain twice the amount of energy as carbohydrates in the same weight.

Question 18

Why are lipids good storage molecules?

Answer 18

A lot of energy can be stored in a small volume

Low mass:energy ratio

Question 19

Why is having lipids not being able to dissolve in water an advantage?

Answer 19

They are large and non polar. This means that they do not affect osmosis when being stored

Question 20

What is the role of lipids in waterproofing?

Answer 20

Lipids are insoluble in water so they repel water making things like leaves waterproof

Question 21

Why are lipids food for thermal insulation?

Answer 21

Fats are slow conductors of heat . Reduce heat loss

Question 22

Why are lipids good for protection?

Answer 22

Lipids separate the organs from one another to help protect them from damage

Question 23

What are phospholipids made up of?

Answer 23

2 fatty acids tails and 1 phosphate and a glycine backbone

Question 24

What makes phospholipids have a hydrophobic region and a water soluble region?

Answer 24

The phosphate makes the phospholipid water soluble

The fatty acid tails make the phospholipid hydrophobic

Question 25

Where are phospholipids usually found?

Answer 25

Cell membranes

Question 26

What is the test for lipids

Answer 26

The emulsion test 
Add 2cm3 of sample and 5cm3 ethanol. 
Shake 
Add 5cm3 of water and shake again 
If it emulsifiers it has lipids in in. If it remains clear there is no lipids