Practise pathogen types, transmission and prevention through cholera, malaria, tuberculosis and HIV contexts, then explain antibiotic action and resistance from evidence.
Which statement correctly describes infectious diseases?
They are diseases caused by environmental factors that are not passed from one person to another.
They are diseases caused by a fault in the DNA that can be passed from a parent to their offspring.
They are diseases caused by a lack of a nutrient in the diet, such as a vitamin or mineral.
They are diseases caused by a pathogen such as a bacterium, fungus, protoctist or virus.
Bacteria may be classified according to differences in cell wall structure. The differences are shown by using the Gram stain.
The diagram shows part of a Gram-positive bacterium and part of a Gram-negative bacterium, drawn to the same scale.
The antibiotic penicillin kills bacteria by inhibiting the synthesis of the cell walls during bacterial cell growth.
Which type of bacteria will be killed by penicillin more easily and why?
Gram-positive bacteria because the peptidoglycan layer is exposed to penicillin directly
Gram-positive bacteria because it has a thinner layer surrounding the cell membrane overall
Gram-negative bacteria because the thin peptidoglycan layer can be broken down faster
Gram-negative bacteria because there is more periplasm available, which gives a weaker structure
Which disease does Mycobacterium bovis cause?
cholera
HIV/AIDS
malaria
tuberculosis
Which statement correctly explains why viruses are unaffected by penicillin?
Penicillin only affects host cell metabolism.
Penicillin only binds with 70 S ribosomes.
Penicillin only blocks mRNA synthesis in prokaryotes.
Penicillin only blocks peptidoglycan synthesis.