Lipids

Question 1

Are triglycerides polar or non-polar?

Answer 1

Non-polar

Question 2

Are triglycerides hydrophobic or hydrophilic?

Answer 2

Hydrophobic

Question 3

What are the monomers?

Answer 3

Glycerol and fatty acids

Question 4

What does glycerol contain?

Answer 4

A hydroxyl group bonded to a carbon atom

Question 5

What do fatty acids contain?

Answer 5

Methyl group at one end of the hydrocarbon chain (R group) and a carboxyl group- ROOH

Question 6

What are the 2 ways fatty acids can vary?

Answer 6

The length of the hydrocarbon chain (the R group)
They can be either saturated or unsaturated

Question 7

What does saturated mean?

Answer 7

All single C-C bonds

Question 8

What does unsaturated mean?

Answer 8

One or more double C=C bonds

Question 9

What are triglycerides formed by?

Answer 9

Esterification

Question 10

When does an ester bond form?

Answer 10

When an OH group and a COOH group form

Question 11

How is water formed?

Answer 11

H from glycerol combines with an OH from the fatty acid to make water

Question 12

What type of reaction forms an ester bond?

Answer 12

A condensation reaction

Question 13

What is released for each ester bond formed?

Answer 13

A H20 molecule

Question 14

What joins to make a triglyceride?

Answer 14

3 fatty acid join to one glycerol molecule

Question 15

What is released for one triglyceride to form?

Answer 15

3 H20 molecules

Question 16

Waterproofing?

Answer 16

Fully hydrophobic
Water molecules are repelled

Question 17

Electrical insulator?

Answer 17

Triglycerides are uncharged— no delocalised electrons
Do not conduct electricity and no moving particles to conduct thermal electricity

Question 18

Do triglycerides conduct electricity?

Answer 18

No- and no moving particles to conduct thermal electricity

Question 19

How do triglycerides increase the speed of transmission of nerve impulses?

Answer 19

Triglycerides are part of the composition of the myelin sheath that surrounds nerve fibres- provides insulation- increases the speed of the transmission of nerve impulses

Question 20

How are triglycerides respiratory substrates?

Answer 20

Oxidising hydrocarbons
Large number of C-H bonds to oxidise- releasing electrons which are used in ATP production

Question 21

How are triglycerides good for buoyancy?

Answer 21

The low density of fat tissue increases the ability of animals to float more easily

Question 22

What do phospholipids consist of?

Answer 22

Only 2 fatty acids bonded to a glycerol molecule

Question 23

What has one of the fatty acids been replaced by?

Answer 23

A phosphate ion

Question 24

Is the phosphate polar, non-polar, hydrophobic or hydrophilic?

Answer 24

Polar (hydrophilic)

Question 25

Is the fatty acid polar, non-polar, hydrophobic or hydrophilic?

Answer 25

Non-polar (hydrophobic)

Question 26

What function of phospholipids makes it form bilayers in water?

Answer 26

It’s amphipathic

Question 27

What are phospholipids the main component of?

Answer 27

Cell membranes

Question 28

What creates a hydrophobic core with a phospholipid bilayer?

Answer 28

The hydrophobic fatty acid tails

Question 29

What does the phospholipid bilayer act as?

Answer 29

A barrier to water-soluble molecules

Question 30

Test for lipids?

Answer 30

1) grind food sample using a pestle and mortar
2) add ethanol to test tube and shake (using a bung)
3) add water to the test tube
4) observe results
5) cloudy emulsion will form if ethanol is present