Explain how enzymes reduce the activation energy needed for reactions to occur.
Folic acid is a molecule needed by all cells for growth. Bacteria cannot absorb folic acid from their surroundings. Bacteria use an enzyme to make a molecule called PABA. PABA is used to make folic acid. An investigation was carried out to assess the effect on PABA production when the concentration of an enzyme inhibitor is increased. Four different concentrations ($1\,\mu\text{M}$ to $30\,\mu\text{M}$) of the inhibitor were used, together with a control with no inhibitor. The concentration of PABA produced in each reaction mixture was measured at $10$ minute intervals. The results are shown in Fig. 2.1.
Use Fig. 2.1 to describe the investigation results.
Outline an experiment that could be carried out to determine whether the inhibitor of the enzyme catalysing the reaction that produces PABA is competitive or non-competitive.
Dietary folic acid can enter human cells, but it cannot cross bacterial cell walls. Human cells do not have an enzyme that makes PABA. Suggest why the inhibitor of this enzyme could be used as a drug to treat bacterial infections in humans.
Suggest why only a few drugs affect viruses.
The development of new antibiotics is important because many bacterial strains are resistant to antibiotics. Suggest two ways to reduce the spread of antibiotic resistance.