Microbiology worksheet with answers

What is an antigen?

1. AA drug that blocks bacterial growth
2. BA type of white blood cell
3. CA protein made by plasma cells to fight infection
4. DA molecule that the immune system recognises

Tapeworms and roundworms are examples of:

1. APrions
2. BHelminths
3. CProtozoa
4. DFungi

Why are viruses called obligate intracellular parasites?

1. AThey always kill the host cell immediately
2. BThey can only be seen inside a cell under a microscope
3. CThey can only replicate inside a living host cell
4. DThey only live inside the intestine

What does an ELISA test detect?

1. ABacterial growth on solid agar plates
2. BSpecific antigens or antibodies, using an enzyme that causes a colour change
3. CThe DNA sequence of the whole bacterial genome
4. DThe shape of bacteria under the microscope

Why are Gram-negative bacteria often harder to treat with antibiotics?

1. ATheir outer membrane blocks many drugs
2. BThey have no ribosomes
3. CThey have a thicker peptidoglycan layer
4. DThey divide much more slowly

In which phase of the bacterial growth curve do the cells divide at their fastest constant rate?

1. ALag (adaptation) phase
2. BStationary (plateau) phase
3. CLog (exponential) phase
4. DDeath phase

A child develops bloody diarrhoea after eating an undercooked burger, then a week later has kidney failure, anaemia and a low platelet count. Which organism is most likely?

1. AShiga toxin-producing E. coli such as O157:H7
2. BRotavirus
3. CStaphylococcus aureus
4. DClostridium perfringens

In Griffith's 1928 experiment, mice died after injection of heat-killed smooth (S) pneumococci mixed with live rough (R) pneumococci. What did this show?

1. AHeat does not kill pneumococci
2. BViruses carry genes between bacteria
3. CRough pneumococci are always more virulent than smooth ones
4. DA "transforming principle" from dead bacteria could change harmless bacteria into virulent ones