Lipids

Question 1

What are lipids?

Answer 1

-compounds insoluble in water but soluble in organic solvents

Question 2

Characteristics of lipids

Answer 2

-waterproofing
-surround cells + mitochondria
-have higher proportion of H to O
-2 types: triglycerides + phospholipids

Question 3

What is the structure of triglycerides?

Answer 3

-fatty acids
-end part = carboxylic group
-mid part = chains of C bonded to H

Question 4

What is a saturated triglyceride?

Answer 4

-only single bonds between C atoms

Question 5

What is an unsaturated triglyceride?

Answer 5

-at least 1 double bonds between C atoms
-mono = 1
-poly = 2

Question 6

Are triglycerides polar molecules?

Answer 6

-no
-they are hydrophobic - don’t dissolve in water
-as there is lots of C + H - lots of energy can be released

Question 7

What is the formation of a triglyceride?

Answer 7

-glycerol + 3 fatty acid react to make = ester bond
-producing water
(Esterfication)

Question 8

What is a phospholipid?

Answer 8

-glycerol molecules bonded to 2 fatty acids

Question 9

What charge do phospholipids have?

Answer 9

-negative charge
-polar = hydrophilic

Question 10

Positioning of phospholipids in water

Answer 10

-hydrophilic head interacts with water
-hydrophobic tails cluster away from the water
-produces a phospholipid bilayer

Question 11

What does cholesterol do?

Answer 11

-stabilises plasma membrane
-has dual HP/H properties
-majority = hydrophobic = so can insert into membrane

Question 12

What are 3 functions of cholesterol?

Answer 12

-starting point for hormones
-used to make vit D in the skin
-used in liver to produce bile