Lipids

Question 1

Describe a triglyceride structure

Answer 1

Has 3 fatty acids and a glycerol - forms 3 ester bonds

Question 2

What’s a saturated fatty acid?

Answer 2

It has no c=c double bonds in the hydrocarbon chain , all the carbons are fully saturated with hydrogen (more energy)

Question 3

What’s an unsaturated fatty acid?

Answer 3

It has one or more c=c double bonds in their hydrocarbon chain creating a bend/kink

Question 4

Explain the properties of triglycerides

Answer 4

Energy store- it is insoluble
Respiration- because of its hydrogen bonds it contains a lot of energy

Question 5

What’s the test for lipids

Answer 5

Add Ethanol and shake
Then add water
If it turns into a milky emulsion then there’s lipid present

Question 6

Describe the structure of a phospholipid

Answer 6

It has a phosphate head which is hydrophobic and 2 fatty acids as well as glycerol

Question 7

Describe the properties of a phospholipid

Answer 7

Forms a bilayer in the cell membrane
The phosphate heads face outwards and the fatty acid tails face inwards.
The head is hydrophilic and the tails are hydrophobic.

Question 8

Describe the structure of fatty acids

Answer 8

Fatty acids are long chains of hydrocarbons with carboxyl groups at the end

Question 9

Describe the structure of glycerol

Answer 9

3 cs in middle surrounded by h but 3 OH at the bottom
These hydroxyl groups can undergo condensation to join to fatty acids or phosphate

Question 10

Describe the formation of triglyceride

Answer 10

One glycerol and 3 fatty acids
Condensation reaction happens and 3 molecules of water are removed
3 ester bonds form
O=C-O

Question 11

Why are membranes with more unsaturated fatty acids more permeable

Answer 11

This is because of the double carbon bonds , they create a kink or bend in the fatty acid which makes it more permeable
As they are less tightly packed increasing movement in the bilayer