Biology · May / June 2023 · Paper 42 · Question 3

correct readings from graph ;

–44 (%) ;;

any three from:

daily doses / use (of erythromycin), peak, 1989 / at 2.8 doses per 1000 people ;

(bacterial) infections (resistant to erythromycin) peak, in 1993 / at 180 bacterial infections per 1000 people ;

no record of resistant infections, until 1991 / from 1983 to 1989 / first 6 years ;

delay (of 4 years) between peak of doses and peak of (resistant) infections ;

any two from:

fewer doses of erythromycin used ;

development of new, antibiotics / treatments / vaccines ;

any example that would cause a reduced usage of antibiotics ;; more, awareness / education about, overuse of antibiotics / antibiotic resistance ;

improved, detection / screening (of pathogens to avoid spread) ; ref to improved, cleanliness / hygiene or more people

vaccinated / population has reached herd immunity ;

isolating infected individuals ;

any five from:

ref to (random) mutations occur (in some of the bacteria) ; (genetic) variation (in ability of bacteria to survive antibiotic treatment) ;

bacteria with (antibiotic) resistance, survive / reproduce ; ora pass on resistant, gene / allele (to offspring / other bacteria) ; increase in frequency of resistant, allele / gene (in the population) ; ref to natural selection / become (better) adapted (for the new environment) ;

AVP ;

any two from:

cell wall ;

circular DNA ;

DNA is, free in cytoplasm / not in a nucleus ;

cell membrane ;

cytoplasm ;

ribosomes ;

unicellular / single-celled (organisms) ;

asexual reproduction ;

movement / swimming / AW ;