1.3 Lipids

Question 1

Why do fats form good waterproofing layers?

Answer 1

lipid tail is hydrophobic so they are insoluble in water

Question 2

What is a structure of a triglyceride?

Answer 2

1 glycerol and 3 fatty acid tails

Question 3

What chemical group does glycerol belong to?

Answer 3

alcohol

Question 4

What are the two different types of fatty acids?

Answer 4

saturated or unsaturated

Question 5

What bond forms between a fatty acid and glycerol in a triglyceride?

Answer 5

esther bond

Question 6

What type of reaction happens when esther bonds form?

Answer 6

condensation

Question 7

What test is used to idenify lipids?

Answer 7

the emulsion test

Question 8

How is the emulsion test carried out?

Answer 8

take equal vol of water and ethanol with food sample
shake
a cloudy white emulsion will form if lipid present

Question 9

What part of the phosphlipid is non-polar?

Answer 9

fatty acid tails

Question 10

What is a respiratory substrate?

Answer 10

any molecule that can be released as energy to create ATP

Question 11

How do animals get energy from a resp substrate?

Answer 11

energy is released by breaking the C-C bonds and C-H bonds

Question 12

Why do lipids store more chemical potential energy than carbs?

Answer 12

lipids have long hydrocarbon tails that contain large amounts of chemical energy which can be released when fatty acids are broken down

Question 13

What elements are present in lipids?

Answer 13

carbon, hydrogen, oxygen

Question 14

Are lipids soluble in water? if no what are they soluble in?

Answer 14

no, soluble in organic solutes like ethanol

Question 15

What are some examples of lipids?

Answer 15

triglycerides - fats and oils
waxes
steroids
cholesterol

Question 16

What are all the functions of lipids?

Answer 16

cell membrane structure
energy store
waterproof
buoyancy

Question 17

What properties of lipids make is a good energy store?

Answer 17

compact - can store more in small space
insoluble - osmotically inert
high energy yeild - x2 the energy released than carbs due to long hydrocarbon tails

Question 18

What property of lipids make them waterproof? and where would it be found?

Answer 18

insoluble to water
eg: waxy cuticles on insects and plants
skin, fur, feathers
animals produce oily secretion on the skin

Question 19

What propery of lipids makes them buoyant?

Answer 19

have a lower density than water

Question 20

What are the two types of lipids?

Answer 20

simple lipids
compound lipids

Question 21

What are simple lipids made of? and an example?

Answer 21

glycerol and fatty acids only
eg: triglycerides

Question 22

What are compound lipids made of and an example?

Answer 22

glycerol, fatty acids and another group/molecule/compound
eg: Phospholipids

Question 23

What is the chemical formula of glycerol?

Answer 23

C3H8O3

Question 24

What is the general formula for fatty acids?

Answer 24

CH3(CH2)nCOOH

Question 25

What does a dotted line in the displayed ans skeletal formula of a fatty acid represent?

Answer 25

the variable group

Question 26

How is a monoglyceride formed?

Answer 26

condensation reaction of a glycerol and fatty acid an OH from the glycerol and the H from the Carboxyl group on fatty acid forms an esther bond

Question 27

What does saturated mean?

Answer 27

full compliment of hydrogens, no double carbon bonds

Question 28

What does unstaturated mean?

Answer 28

double bond in the hydrocarbon tail, not completely saturated with hydrogens

Question 29

What does polyunsaturated mean?

Answer 29

more than 1 c=c double bond

Question 30

What is the difference between unsaturated and saturated fatty acids melting points?

Answer 30

saturated has a higher boiling point unsaturated has a lower boiling point

Question 31

What state is a saturated fatty acids at room temp?

Answer 31

solid

Question 32

What state is a unsaturated fatty acid at room temp?

Answer 32

liquid

Question 33

Which fatty acid (saturated/unsaturated) is worse for your diet?

Answer 33

saturated is worst for your diet as high intake can increase the risk of coronary heart diseases

Question 34

What group does a phospholipid contain?

Answer 34

phosphate group

Question 35

How many tails does a triglyceride have?

Answer 35

3

Question 36

How many tails does a phospholipid have?

Answer 36

2

Question 37

What makes up the phospholipids head?

Answer 37

glycerol and phosphate

Question 38

why are unsaturated fatty acids liquid at room temp?

Answer 38

the double bonds cause the molecule to bend so they cannot pack together so closely

Question 39

Why are triglycerides a good source of energy?

Answer 39

they have long hydrocarbon chains that contain large amounts of chemical energy which can be released when fatty acids are broken down

Question 40

Why are tryglycerides good storage molecules?

Answer 40

they are insoluble and do not affect water potential they form insoluble lipid droplets inside cells (micelles)

Question 41

How are tryglycerides insoluble?

Answer 41

large and non-polar

Question 42

Are fatty acid molecules hydrophyllic or hydrophobic?

Answer 42

hydrophobic

Question 43

Are phospholipids polar or non-polar?

Answer 43

polar - hydrophyllic head and hydrophobic tail

Question 44

What happens when a phospholipid combines with carbohydrates?

Answer 44

forms a glycolipid which are important in cell recognition

Question 45

How is a triglyceride formed?

Answer 45

1 glycerol and 3 fatty acids condensation reaction to join them and the removal of 3 water molcules 3 esther bonds form