Lipids

Question 1

What do lipids contain?

Answer 1

Carbon, hydrogen and oxygen.

Question 2

What is smaller in carbohydrates then in lipids?

Answer 2

The proportion of oxygen to carbon and hydrogen.

Question 3

What are lipids in water?

Answer 3

Insoluble.

Question 4

What are lipids soluble in?

Answer 4

Organic solvents such as alcohols and acetone.

Question 5

What are the main groups of lipids?

Answer 5

Triglycerides and phospholipids.

Question 6

What are triglycerides?

Answer 6

Fats and oils.

Question 7

What are the roles of lipids?

Answer 7

Source of energy, waterproofing, insulation, protection and in cell membranes.

Question 8

Why are lipids used for waterproofing?

Answer 8

They are insoluble in water.

Question 9

What is an example of lipids being used for waterproofing?

Answer 9

Plants and insects have waxy, lipid cuticles that conserve water.

Question 10

Why are lipids used as insulation?

Answer 10

Fats are slow conductors of heat.

Question 11

What are fats at room temperature?

Answer 11

Solid.

Question 12

What are oils at room temperature?

Answer 12

Liquids.

Question 13

Why are triglycerides called triglycerides?

Answer 13

They have three fatty acids combined with a glycerol.

Question 14

What bond does each fatty acid form with glycerol?

Answer 14

Ester bond.

Question 15

In what reaction does an ester bond form?

Answer 15

Condensation reaction.

Question 16

What does hydrolysis of a triglyceride produce?

Answer 16

Glycerol and three fatty acids.

Question 17

What is the worded formula for a triglyceride?

Answer 17

Glycerol+3 fatty acids—>triglyceride+3 waters.

Question 18

What happens if the glycerol molecule in all triglycerides are the same?

Answer 18

The differences in the properties of different fats and oils come from variations in the fatty acids.

Question 19

How many different fatty acids are there?

Answer 19

Over 70.

Question 20

What do all fatty acids have?

Answer 20

A carboxyl group with a hydrocarbon chain attached.

Question 21

When is a fatty acid described as saturated?

Answer 21

When the fatty acids hydrocarbon chain has no carbon-carbon double bonds.

Question 22

Why do we call fatty acids with no carbon-carbon double bonds saturated?

Answer 22

All carbon atoms are linked to the maximum possible number of hydrogen atoms.

Question 23

What do we call a fatty acid with a single bond between carbons in the hydrocarbon chain?

Answer 23

Mono-unsaturated.

Question 24

What do we call a fatty acid with more then one double bond between carbons in the hydrocarbon chain?

Answer 24

Polyunsaturated.

Question 25

Why are triglycerides an excellent source of energy?

Answer 25

They have a high ratio of energy storing carbon-hydrogen bonds to carbon atoms.

Question 26

What is a benefit of triglycerides having a low mass to energy ratio?

Answer 26

They make good storage molecules as much energy can be stored in a small volume.

Question 27

What kind of molecules are triglycerides?

Answer 27

Large, non-polar molecules.

Question 28

What is a result of triglycerides being large, non-polar molecules that are insoluble?

Answer 28

Their storage doesn’t affect osmosis in cells or the water potential of them.

Question 29

What is a benefit of triglycerides having a high ratio of hydrogen to oxygen atoms?

Answer 29

They release water when oxidised and therefore provide an important source of water.

Question 30

How are phospholipids different from lipids?

Answer 30

One of the fatty acids is replaced by a phosphate molecule.

Question 31

What are fatty acids in water?

Answer 31

Hydrophobic.

Question 32

What are phosphate molecules in water?

Answer 32

Hydrophilic.

Question 33

What is a phospholipid made from?

Answer 33

A hydrophilic head and a hydrophobic tail.

Question 34

What are molecules with two ends (poles) called?

Answer 34

Polar.

Question 35

What do phospholipids form in aqueous solutions?

Answer 35

A bilayer within cell surface membranes.

Question 36

Where are the hydrophilic phosphate heads held?

Answer 36

At the surface of the cell surface membrane.

Question 37

What can form from a phospholipid and carbohydrate?

Answer 37

A glycolipid.

Question 38

What are glycolipids important in?

Answer 38

Cell recognition.