Question 18M.2.HL.TZ2.4
| Date | May 2018 | Marks available | [Maximum mark: 8] | Reference code | 18M.2.HL.TZ2.4 |
| Level | HL | Paper | 2 | Time zone | TZ2 |
| Command term | Explain, State | Question number | 4 | Adapted from | N/A |
The diagram shows alpha amylase.
Explain the secondary structure of this protein molecule.
[3]
a. secondary structure includes alpha helices/beta pleated sheets
b. secondary structure «of this protein» consists «mainly» of alpha helices
c. spiral coils «of polypeptide chain» held together by hydrogen bonds
d. between oxygen «C=O» and hydrogen atoms «N−H» of amino acids«on backbone»
e. «some» beta pleated sheets present in this protein
Amylase is used in human digestion.
State two sites of production of amylase.
[1]
salivary glands AND pancreas
Both needed.
Amylase is used in human digestion.
State the function of amylase.
[1]
breaks down starch «by hydrolysis» into maltose/disaccharides
Explain how enzymes catalyse chemical reactions.
[3]
a. enzymes work by forming enzyme–substrate complexes
b. binding of substrate«s» to active site «of enzyme»
c. «enzyme» changes shape slightly
OR
puts strains on chemical bonds «of substrate»
d. decreases activation energy / increases rate of reaction
e. enzymes bind to specific substrates
Can show these points in an annotated diagram.