Module 1Ab - Lipids

Question 1

(2)

Give two types of lipids.

Answer 1

• Triglycerides
• Phospholipids

Question 2

(1)

Lipids are not polymers but…

Answer 2

MACROMOLECULE

Question 3

(1)

Lipids are un-polar molecules.
What is meant by the term ‘un-polar’

Answer 3

They’re unable to dissolve in water

Question 4

(3)

How does the structure of a triglyceride differ from a phospholipid?

Answer 4

Triglycerides:
- 1 glycerol
- 3 fatty acids

Phospholipids:
- 1 glycerol
- 2 fatty acids
- 1 phosphate group

Question 5

(3)

Glycerol and propanol are both alcohols.

Compare the two alcohols.

Answer 5

• Both are ORGANIC alcohols
• Propanol has 1 hydroxyl group to a carbon atom
• Glycerol has 3 hydroxyl groups, each bonded to three other carbon atoms.

Question 6

(1)

Fatty acids have a similar structure to…

Answer 6

carboxylic acids.

Question 7

(3)

What is an ester bond?

Answer 7

• A covalent bondformed by a condensation reaction
• between the -OH group of carboxylic acid
• AND the -OH group of an alcohol.

Question 8

(1)

Fatty acids with no double bond to carbon atoms are…

Answer 8

SATURATED.

1 Carbon double bond = Monounsaturated, many carbon bond=polyunsaturated

Question 9

(2)

Saturated fatty acids make a triglyceride also known as a…

Answer 9

Fat ( in solid state)

Question 10

(2)

Unsaturated fatty acids make a triglyceride also known as a…

Answer 10

Oils (in liquid state)

Question 11

(4)

Explain how the breakdown of a triglyceride is used in respiration.

Answer 11

• Triglyceride breaks down into 1 glycerol and 3 fatty acids
• During a hydrolysis reaction
• Oxygen is formed which is required for respiration in…
• Glucose + oxygen –> water + CO2 + ATP

Question 12

(3)

In a condensation reaction of bonding phosphoric acid and glycerol, how is a phosphate ester bond formed?

Answer 12

• Phosphoric acid dissociates its H+ ions in water
• Forming PO4 (phosphate group) which has a charge of 3-.
• This negative charge causes the phospholipid head to be HYDROPHILIC.

Question 13

(2)

Fatty acids of a phospholipid are non-polar and left uncharged meaning that…

Answer 13

• fatty acids are able to repell water
• making them HYDROPHOBIC molecules.

Question 14

(2)

A phospholipid monolayer has a layer of water in a phospholipid.

Explain how a phospholipid bilayer functions.

Answer 14

• Two layers of the phsopholipid
• A mirroring pair of hydrophobic and hydrophilic layers.

Question 15

(3)

Explain how the membrane of a phospholipid is kept stable.

Answer 15

• Phospholipids able to move past each other
• Making the membrane fluid
• NEVER EXPOSES HYDROPHOBIC TAILS to water.
• ensuring its stability.

Question 16

(3)

Why can oxygen and carbon dioxide move through the phospholipid bilayer?

Answer 16

• Small molecules
• that are NON-POLAR
• required for IMPORTANT SYSTEMS (e.g: respiration and diffusion)