Proteins

Question 1

How are proteins formed

Answer 1

condensation reaction

Question 2

What colour does acidified potassium dichromate become when its oxidised

Answer 2

orange—- blue/green

Question 3

What does tollens reagent becomes when its oxidised

Answer 3

forms a silver mirror

Question 4

What colour does benedicts reagent turn when its oxidised

Answer 4

blue—- orange/red

Question 5

Which gas reacts with edible oils to give food a rancid flavour

Answer 5

oxygen

Question 6

What test could be used to distinguish fats from oils

Answer 6

unsaturated compounds quickly decolourise bromine solution

Question 7

Glycerol can be obtained from fats by which process

Answer 7

hydrolysis

Question 8

Name the type of compound produced by the hydrolysis of a protein during digestion

Answer 8

amino acids

Question 9

What can be used to tell the difference between an aldehyde and a ketone?

Answer 9

Aldehydes will react with acidified potassium dichromate while ketones will not.

Question 10

What happens when proteins denature

Answer 10

hydrogen bonds are broken

Question 11

What name is given to the link in protein molecules that holds the amino acid molecules together

Answer 11

amide/peptide links

Question 12

What is meant by the term denatured

Answer 12

changes shape

Question 13

Explain why protein chains unwind when they are heated

Answer 13

heat breaks the hydrogen bonds

Question 14

State what is meant by an essential amino acid.

Answer 14

Amino acid that must be obtained from the diet.

Question 15

State the term used for the process of breaking down a protein by enzyme action in the body

Answer 15

digestion

Question 16

State why our bodies need amino acids

Answer 16

to build proteins

Question 17

State the name of the functional group found in all enzyme

Answer 17

peptide link

Question 18

Describe the breakdown of proteins

Answer 18

peptide links are broke down to form amino acids

Question 19

Explain what happens to an enzyme when it is cooked

Answer 19

enzyme becomes denatures and hydrogen bonds are broken

Question 20

Why are proteins needed in our diet

Answer 20

for growth and repair of body tissue

Question 21

What colour does fehlings reagent turn when it is oxidised

Answer 21

blue to brick red

Question 22

Explain fully what happens when a protein is denatured

Answer 22

hydrogen bonds are broken and the protein changes shape

Question 23

What happens when proteins in food are denatured

Answer 23

texture changes when it is cooked

Question 24

State the name of the digestion process where enzymes break down proteins into amino acids

Answer 24

Hydrolysis

Question 25

Explain fully why consuming protein in the diet can provide the body with essential amino acids

Answer 25

During digestion enzyme hydrolysis of dietary proteins can produce amino acids some of which will be essential amino acids In a hydrolysis reaction proteins react with water breaking down into the smaller amino acids

Question 26

Explain fully why consuming protein in the diet can provide the body with essential amino acids

Answer 26

During digestion enzyme hydrolysis of dietary proteins can produce amino acids some of which will be essential amino acids In a hydrolysis reaction proteins react with water breaking down into the smaller amino acids