past paper questions

Question 1

putting bee honey on a cut kills bacteria. honey contains a high concentration of sugar.

use your knowledge of water potential to suggest how putting honey on a cut kills bacteria.

Answer 1

1- water potential is lower in honey than bacterial cell
2- water leaves bacteria / cell by osmosis
3- therefore stops metabolic reactions

Question 2

the % of population vaccinated doesn’t need to be 100% to be effective in preventing the spread of pathogens. explain why.

Answer 2

1- more people are immune / fewer people carry the pathogen
2- unvaccinated people less likely to contact infected people

Question 3

explain how the monoclonal antibody would prevent the regulator protein from working.

Answer 3

1- antibody have complementary binding site / specific tertiary structure
2- binds to protein / forms antigen-antibody complex
3- so regulator protein doesn’t fit / not complementary / bind to receptor