Lipids

Question 1

Are lipids polymers? and why?

Answer 1

• No because they do not have repeating units

Question 2

What are the two main groups of lipids?

Answer 2

• Triglycerides and phospholipids

Question 3

What bonds hold lipids together?

Answer 3

Ester bonds (RCOOH)

Question 4

How are triglycerides formed?

Answer 4

Via the condensation reaction between one glycerol and 3 fatty acids

Question 5

Can you draw a triglyceride?

Answer 5

Search if you got it right

Question 6

Can you draw an ester bond?
hint: it only includes oxygen and carbon

Answer 6

Search if you got it right?

Question 7

How many condensation reactions take place to form a triglyceride?

Answer 7

Three

Question 8

What does mean R?

Answer 8

Variable group

Question 9

what is the structure of phospholipids?

Answer 9

Glycerol, two fatty acids and a phosphate group

Question 10

Can you draw a phospholipid

Answer 10

Search it up if you got it right

Question 11

List the two types of fats?

Answer 11

Unsaturated and saturated

Question 12

State the difference between saturated and unsaturated fats.

Answer 12

Saturated fats do not contain a single double bond between their carbon atoms. while unsaturated fats have at least one double bond between the carbon atoms.

Question 13

What is the function of the high ratio of hydrocarbons in triglycerides?

Answer 13

to store twice as much energy as carbohydrates

Question 14

why is oxidation useful in triglycerides?

Answer 14

to release water which is useful for desert animals

Question 15

are triglycerides soluble or insoluble and how does it affect a cell

Answer 15

it is insoluble so it does not affect water potential and prevents osmosis

Question 16

All fatty acids have the same basic structure but…

Answer 16

Their tails vary

Question 17

why are triglycerides insoluble?

Answer 17

because they have hydrophobic tails

Question 18

How does the tails in fatty acids vary?

Answer 18

in hydrocarbon tail and location

Question 19

Are phospholipids soluble and why?

Answer 19

they are soluble due to their hydrophilic (water-loving heads) but their tails are hydrophobic (water-hating)

Question 20

What is the function of phospholipids?

Answer 20

To form a bilayer in the cell membrane and serve as a selectively permeable membrane

Question 21

How do phospholipids act as a membrane?

Answer 21

Hydrophobic tails prevent water-soluble substances from passing through

Question 22

how is the bilayer formed?

Answer 22

hydrophilic heads face outwards and hydrophobic heads face inwards

Question 23

What is formed when carbohydrates react with lipids

Answer 23

Glycolipids

Question 24

which lipid has more hydrogens and why?

Answer 24

Triglycerides because they do not have double bonds between their carbon atoms

Question 25

what makes phospholipids hydrophilic?

Answer 25

Phosphate group

Question 26

What test is used for lipids

Answer 26

Emulsion test

Question 27

Describe the emulsion test

Answer 27

• Add ethanol/ alcohol to the food sample and shake
• Add distilled water and gently shake
• The reaction is positive if the sample forms a white, milky, cloudy emulsion

Question 28

why are hydrophobic tails insoluble?

Answer 28

Because they are non-polar