The rate of hydrolysis of protein, using an enzyme, was studied at different temperatures. Which of the following graphs would be obtained?

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Essential amino acids are defined as the amino acids which

• are necessary for building proteins

• humans must acquire through their diet

• plants cannot synthesise for themselves

• are produced when any protein is hydrolysed.

Molecule X has the structure shown.

Which of the following could be produced by partial hydrolysis of X?

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Uncooked egg white is mainly composed of dissolved proteins. During cooking processes, the proteins become denatured as the protein chains unwind, and the egg white solidifies. Why do the protein chains unwind?

• the protein is hydrolysed

• the molecules do not collide with the correct geometry

• the protein becomes an emulsifier

• Heat breaks hydrogen bonds

Once cooked and eaten, the digestive system breaks protein chains into amino acids with the help of enzymes.

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

• condensation

• hydrolysis

• hydrogenation

• reduction

State how many amino acid molecules joined to form this section of protein?

• 4

• 5

• 6

• 7

What type of chemical structure does a protein have?

• ester

• polymer

• fatty acid

• hydrocarbon

Which of the following is an example of a protein?

• oils

• fats

• soap

• enzymes

Which of these does not apply to proteins?

• They form major structural materials of animal tissue

• They help with the maintenance and regulation of life processes

• The provide a rich energy source

• They can form spirals, sheets, or other complex shapes

Amino acids contain

• an amine group and a carbonyl group

• an amine group and a carboxyl group

• an amide group and a carbonyl group

• an amide group and a carboxyl group