6) PROTEINS & THE CHEMISTRY OF COOKING

Question 1

What sub units make up proteins

Answer 1

Amino acids

Question 2

What are the functional groups in a amino acid

Answer 2

Amino group

Carboxyl

Question 3

What are essential amino acids

Answer 3

Amino acids that we need to get from our diet as our bodies don’t make them itself

Question 4

What kind of reaction is the making of a protein

Answer 4

Condensation

Question 5

What link is formed when amino acids join

Answer 5

Amide link

Question 6

Where does the OH and H come in the formation of a protein

Answer 6

OH from Acid

H from amino group

Question 7

What kind of reaction do we use to break up a protein

Answer 7

Hydrolysis

Question 8

Why do more volatile foods have more flavour

Answer 8

More volatile foods have more flavour because what we call flavour is mostly smell

To smell gas molecules gases must evaporate up your nose

Therefore more volatile foods have more flavour as they are easily evaporated meaning more gas molecules can get up your nose

Question 9

Does asparagus flavour dissolve in water or oil?
What would happen if you boil it
What would happen if you fry it

Answer 9

Asparagus flavour dissolves in water

• If we fry it the flavour remain
• if we boil it the flavour is dissolved in the water and lost

Question 10

Does broccoli flavour dissolve in water or oil?
What would happen if you boil it
What would happen if you fry it

Answer 10

Broccoli flavour dissolves in oil

• if we boil it the flavour remains
• if we fry it the flavour dissolves in the oil and is lost

Question 11

What does the regular size (N-C-C) of amino acids allow

Answer 11

Hydrogen bonding

Question 12

What does the hydrogen bonding in amino acids allow

Answer 12

To bend to form proteins

Question 13

Why is it important for proteins to have a specific shape

Answer 13

The specific shape allows the protein to catalyse a specific reaction

Question 14

What are the 2 shapes of proteins you can get

Answer 14

Fibrous

Globular

Question 15

Describe fibrous proteins

Answer 15

Fibrous proteins are long and thin

•they are structural material like:

• skin
• hair
• finger nails

•they are not soluble so non polar

Question 16

Describe globular proteins

Answer 16

Globular proteins are spiral chains folded into complex chains

•they are involved in the maintenance of life processes:

• enzymes
• hormones

•they are soluble, so polar

Question 17

What happens to proteins when cooked

Answer 17

• Hydrogen bonds between amino acids are broken causing the shape of the protein to be changed, denaturing it.
• this causes changed in flavour, texture and colour