Lipids

Question 1

List seven functions of lipids

Answer 1

Thermal and electrical insulation, cell membranes, energy source and storage, metabolic water, protection of organs from physical damage, waterproofing and buoyancy, steroid hormones

Question 2

What elements do lipids contain?

Answer 2

Carbon, hydrogen and oxygen (plus phosphorus in phospholipids)

Question 3

What are triglycerides made of?

Answer 3

Glycerol and three fatty acids joined in condensation reactions

Question 4

What are phospholipids made of?

Answer 4

Glycerol, two fatty acids and a phosphate group joined in condensation reactions

Question 5

Will fatty acids dissolve in water?

Answer 5

No, because they are nonpolar. They can dissolve in nonpolar solvents

Question 6

What is an unsaturated fatty acid?

Answer 6

Unsaturated contain double C=C bonds and carbons are not bonded to the maximum number of hydrogens

Question 7

What is a saturated fatty acid?

Answer 7

Saturated only contain single C-C bonds, and carbons are bonded to the maximum number of hydrogens.

Question 8

What is an polyunsaturated fatty acid?

Answer 8

Polyunsaturated have two or more C=C double bonds

Question 9

What is a monounsaturated fatty acid?

Answer 9

Monounsaturated have one C=C double bond

Question 10

Why are lipids a better energy store than carboyhydrates?

Answer 10

1g of lipid releases twice as much energy as 1g of carbohydrate

Question 11

Plant oils are liquid at room temperature. Which type of fatty acid do the triglycerides mostly contain?

Answer 11

Unsaturated fatty acids. The double bonds cause kinks in the chain, meaning molecules will be pushed further apart.

Question 12

Animal fats are solid at room temperature. Which type of fatty acid do the triglycerides mostly contain?

Answer 12

Saturated fatty acids. These have straight chains, so molecules are closer together

Question 13

What bond is formed by a condensation reaction in lipids?

Answer 13

Ester

Question 14

Which parts of a phospholipid are hydrophilic and hydrophobic?

Answer 14

The phosphate and glycerol and hydrophilic, the fatty acids hydrophobic (nonpolar)

Question 15

A high intake of saturated fat raises production of … in the … which can cause plaques called…

Answer 15

A high intake of saturated fat raises production of low density lipoprotein cholesterol in the liver which can cause plaques called atheromas

Question 16

A high intake of unsaturated fat raises production of … in the … which can reduce the number of plaques called…

Answer 16

A high intake of unsaturated fat raises production of high density lipoprotein cholesterol in the liver which can reduce atheromas

Question 17

The disease which involves formation of plaques in arteries is called

Answer 17

Atherosclerosis. The plaques are called atheromas