Microbiology worksheet with answers

What is the main function of bacterial flagella?

1. AStorage of nutrients
2. BProtection against drying out
3. CAttachment to host cells
4. DMovement

What is a plasmid?

1. AThe protein coat of a virus
2. BA small circle of DNA separate from the bacterial chromosome
3. CA layer of sugar around the bacterial cell that protects it from phagocytosis
4. DA type of bacterial ribosome

What is an obligate anaerobe?

1. AAn organism that needs oxygen to grow
2. BAn organism that grows both with and without oxygen present
3. CAn organism that lives only in the lungs
4. DAn organism that cannot grow in the presence of oxygen

What is the incubation period?

1. AThe time an antibiotic takes to work
2. BThe time a culture needs in the laboratory
3. CThe time during which a patient remains infectious to others
4. DThe time between infection and the first symptoms

Tetanus and diphtheria vaccines are toxoids. What does that mean?

1. AThey contain live bacteria that cannot make toxin
2. BThey contain an inactivated toxin that still triggers an immune response
3. CThey contain the bacterial DNA only
4. DThey contain ready-made antibodies against the toxin, giving passive immunity

How is DNA transferred between bacteria during conjugation?

1. ABy a bacteriophage carrying bacterial DNA
2. BThrough direct contact using a sex pilus
3. CBy uptake of free DNA from the environment
4. DBy fusion of two bacterial cells into one

Corynebacterium diphtheriae causes diphtheria only if it produces diphtheria toxin. When does it make this toxin?

1. AOnly when it is grown at high temperature
2. BWhen it carries a bacteriophage with the toxin gene
3. CWhenever it is exposed to antibiotics
4. DOnly after it has conjugated with E. coli and received a plasmid

Which hepatitis viruses are mainly spread through contaminated food and water?

1. AHepatitis C and E
2. BHepatitis B and C
3. CHepatitis A and E
4. DHepatitis B and D