First 304 words of the document:
Vancomycin is an antibiotic that kills bacterial cells by preventing the synthesis of
peptidoglycan, a component of bacterial cell walls.
State the term used to describe antibiotics, such as vancomycin, that kill bacterial cells.
Suggest how bacterial cells are killed by vancomycin. (2 marks)
Cell wall is weaker (cannot form properly)
Cell wall bursts during division.
Explain why doctors have been advised to limit the prescription of antibiotics. (2 marks)
Antibiotics act as selection pressures
Some bacteria are resistant to the antibiotic
Resistant bacteria survive and pass on the resistance to the next generation.
Therefore the antibiotic is no longer affected.
Some infections cannot be treated by antibiotics.
Describe how you could investigate the effect of different antibiotics on bacteria. (4 marks)
Bacteria is distributed evenly e.g. by lawn spreading
Paper discs soaked in antibiotics are placed onto the plate.
There is control of antibiotic concentration.
Aseptic techniques are used
Plate is incubated at 25-35 degrees
The inhibition zone shows how effective an antibiotic is.
Replication with same bacteria improves reliability
Repetition with different bacteria also improves reliability.
State two ways in which the skin flora can help to protect a person from infection by
pathogenic bacteria. (2 marks)
Competition for nutrients
Competition for space
Stimulation of skin immune system
Secretion of chemicals affecting pH
Influenza (flu) is caused by a virus. Sometimes antibiotics are used as part of the treatment
for a person with influenza. Suggest why antibiotics may be used as part of the treatment
for influenza. (2 marks)
Influenza may allow the development of other diseases e.g. opportunistic infections
Antibiotics will kill/ inhibit the growth of bacteria.