1.3: Lipids

Question 1

What 3 elements are lipids made of

Answer 1

carbon, hydrogen, oxygen

Question 2

Why do lipids form good waterproofing layers?

Answer 2

because they are insoluble in water

Question 3

State 3 properties of lipids

Answer 3

compact
insoluble
high energy yield

Question 4

State 7 functions of lipids

Answer 4

thermal insulation
cell membrane structure
energy store
waterproofing
source of metabolic water
buoyancy
protection

Question 5

what is the structure of a triglyceride

Answer 5

simple lipid - 3 fatty acids bonded to one glycerol

Question 6

what is the structure of compound lipids

Answer 6

glycerol, fatty acids and a group/molecule/compound

Question 7

What is the chemical formula of glycerol

Answer 7

C3H8O3

Question 8

What is the general formula of fatty acids

Answer 8

CH3(CH2)nCOOH

Question 9

what chemical group does glycerol belong to?

Answer 9

alcohols

Question 10

What are 2 different types of fatty acids?

Answer 10

saturated and unsaturated

Question 11

what is the difference between a saturated fatty acid and an unsaturated fatty acid?

Answer 11

sat = only single bonds between its carbon atoms
unsat = at least one double bond between its carbon atoms

Question 12

what type of reaction takes place when a triglyceride is formed

Answer 12

condensation reaction

Question 13

what is the name of the bond that forms between a fatty acid and glycerol to form triglyceride

Answer 13

ester bond

Question 14

how is an ester bond formed between a fatty acid and glycerol

Answer 14

a hydroxyl group from glycerol and a hydrogen atom from the fatty acid are removed to form a molecule of water and forming an ester bond between glycerol and the fatty acid, hence, a triglyceride is formed

Question 15

what is the difference in unsaturated and saturated fatty acids in terms of their complement of hydrogen atoms

Answer 15

sat = has its full complement of hydrogens as there are no C=C double bonds in its hydrocarbon tail whereas unsat does not have its full complement of hydrogens as there is at least one C=C double bond in its hydrocarbon tail

Question 16

Compare the melting point of an unsaturated and saturated fatty acid and why

Answer 16

saturated = higher
unsat = lower
as sat has its full complement of hydrogen atoms

Question 17

What is the state of saturated and unsaturated fatty acids at room temperature

Answer 17

sat = solid
unsat = liquid

Question 18

What does a high intake of saturated fats lead to in relation to cardiac health

Answer 18

high intake of saturated fats = increased risk of heart disease

Question 19

why do lipid molecules store more chemical potential energy than carbohydrates

Answer 19

there are more C-H and C-C bonds in lipids than in carbohydrates

Question 20

define what a respiratory substrate is

Answer 20

any molecule used to release energy to be used to create ATP

Question 21

How do animals get energy from a respiratory substrate?

Answer 21

oxidation

Question 22

what do phospholipids consist of

Answer 22

glycerol, fatty acid and phosphate ion
hydrophobic tails (fatty acids)
hydrophilic head (phosphate ion)

Question 23

State the 2 key differences between the structure of a triglyceride and a phospholipid

Answer 23

triglyceride has 3 fatty acid tails and has glycerol as its head
phospholipid has 2 fatty acid tails and has glycerol and phosphate as its head