B1 Specimen

Question 1

Give factors that could be controlled in an enzyme experiment

Answer 1

Concentration of enzyme
Concentration of substrate
pH of mixture

Question 2

Explain the difference in the rates of reaction at 60o and 37o between 20 and 40 minutes

Answer 2

At 60o the enzymes denatures and reaction stops because the active site changes
At 37o the substrates are still available but not converted to products

Question 3

Describe how oxygen in the air reaches capillaries surrounding alveoli in the lungs

Answer 3

Trachea, bronchi, bronchioles
Down pressure gradient
Down concentration gradient
Across alveolar epithelium
Across capillary endothelium

Question 4

Explain how cellulose molecules are adapted for their function in plant cells

Answer 4

Many weak hydrogen bonds which provide strength
Long straight chains

Question 5

In transport across membranes what can you say about the plateaued line

Answer 5

It is in equilibrium

Question 6

Name the 7 taxons

Answer 6

DKPCOFGS
Domain
Kingdom
Class
Order
Family
Genus
Species

Question 7

Describe the behaviour of chromosomes during interphase and meiosis

Answer 7

DNA replication
Homologous chromosomes separate
Sister chromatids separate

Question 8

Describe how proteins are digested in the human gut

Answer 8

Hydrolysis of peptide bonds
Endopeptidases break polypeptides into smaller peptide chains
Exopeptidases remove terminal amino acids
Dipeptidases hydrolyse dipeptides into single amino acids