fats + oils

Question 1

what is a triglyceride?

Answer 1

• molecules contain fats and oils

- large non-polar molecules

Question 2

what is a triglyceride made of?

Answer 2

a glycerol and 3 fatty acids

Question 3

how are triglycerides formed?

Answer 3

formed by a condensation reaction. The 3 fatty acid chains ‘connected’ to each glycerol molecule

Question 4

how is the ester link formed?

Answer 4

by the hydroxyl group reacting with the carboxyl group.

There are 3 ester links in 1 molecule of triglyceride

Question 5

what are some properties of triglycerides?

Answer 5

• are non-polar and unable to form H bonds with water- they are hydrophobic
• less dense than water because of the large sections of non-polar molecules

Question 6

what types of fats are there?

Answer 6

• saturated
• unsaturated
• monounsaturated
• polyunsaturated

Question 7

describe a saturated fatty acid

Answer 7

a fatty acid chain that has all single bonds.

Question 8

describe an unsaturated fatty acid

Answer 8

contain one or more double or triple bonds between the molecules. These fats are liquid at room temperature in oil form.

Question 9

describe a monounsaturated fatty acid

Answer 9

A fatty acid having one carbon-carbon double bond in its carbon chain.

Question 10

describe a polyunsaturated fatty acid

Answer 10

more than one carbo-carbon double bond. The two major classes of polyunsaturated fats are omega-3 and omega-6 fatty acids.

Question 11

what is hydrogenation?

Answer 11

the addition of two hydrogen atoms to unsaturated double bonds (C=C) in the fatty acid moieties of the triglycerides. The more saturated fat resulting from this reaction has a higher melting point than the starting material

Question 12

describe the melting points for saturated fatty acids?

Answer 12

• the different melting points can be explained in terms of length and degree of saturation of their fatty acid hydrocarbon chain.
• as the hydrocarbon increases in length the melting point increases

Question 13

what happens to intermolecular forces with fatty acids?

Answer 13

• the fatty acid tails can pack closely and so the intermolecular forces become stronger

Question 14

what happens to dispersion forces with fatty acids?

Answer 14

the strength of the dispersion forces increase between the fatty acids molecules as the molecular mass increases

Question 15

describe the melting point in unsaturated fatty acid

Answer 15

-when the C=C bonds increase the melting point of the unsaturated fatty acid DECREASES

Question 16

do unsaturated fatty acids have weak or strong dispersion forces?

Answer 16

they are much weaker than those formed between saturated fatty acids

Question 17

what are essential fatty acids?

Answer 17

unsaturated fatty acids that are essential to human health and cannot be manufactured in the body
- two types: linoleum acid and a-linoleic acid

Question 18

what are nonessential fatty acids?

Answer 18

various amino acids that are required for normal health and growth that can be synthesised by the body
- include arachidic acid, stearic acid etc

Question 19

difference between omega 3 and omega 6 fats

Answer 19

omega 3 refers to the the 3rd carbon atom with the first double bond from the methyl end whereas omega 6 is the same however on the 6th