Staphylococcus aureus is a bacterial species that causes infections in humans. Antibiotic-resistant strains, such as MRSA, have become a common cause of infection acquired when in hospital.
Explain how the use of antibiotics has led to antibiotic-resistant strains of bacteria becoming a common cause of infection acquired when in hospital.
Scientists suggested that factors other than antibiotic use led to the increase in MRSA infections. One suggested factor is people eating more maltose in their diet.
Maltose is a disaccharide. Name another disaccharide that contains a glucose monomer.
Describe how the scientists could use aseptic techniques to transfer 0.5 cm30.5\text{ cm}^30.5 cm3 of S. aureus in liquid culture from a flask onto an agar plate.
Scientists investigated the effect of maltose on the growth rate of S. aureus. They grew populations of non-resistant and MRSA strains on separate agar plates with:
They measured the growth rate of the bacteria. Figure 1 shows the scientists' results.
Use Figure 1 to evaluate whether more maltose in the diet could be a factor in the increased number of MRSA infections.
Practise AQA A Level Biology Evolution may lead to speciation (A-level only) with exam-style questions for A Level Biology. 9 questions, matched to the AQA A Level Biology (7402) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
