Microbiology Pre-Matriculation Review Answers
The answers to the questions are shown in blue text.
1. What are the two major components of the bacterial envelope?
Cell Wall and Cell Membrane
2. What is the main function of a bacterial capsule?
Virulence factor that protects against phagocytosis
3. What is Gram staining?
A procedure to classify bacteria by the ability of the cell wall to absorb a crystal violet
dye followed by a red safranin counter stain.
4. What color are Gram-negative bacteria?
Pink, because they do not retain the crystal violet dye but do take up the red safranin
counter stain.
5. What are the three components of LPS?
O-antigen, middle core polysaccharide, inner Lipid A
6. What are two types of pili and what are there functions?
Common pili (fimbriae) mediate adhesion and sex pili allow for exchange of genetic
material.
7. What advantage does spore formation offer bacteria?
To ensure survival in a harsh environment; Highly resistant to heat, chemicals and
radiation
8. During what phase is bacterial growth the fastest?
Log phase
9. What are the four phases of bacterial growth?
Lag, Log, Stationary, and Death
10. In what phase does bacterial growth equal that of bacterial death?
Stationary phase
11. By what process do bacteria multiply?
Binary fission
12. Name two types of DNA forms found in bacteria?
Chromosomal and plasmid DNA
13. Describe the DNA structure of plasmids?
Double-stranded circular DNA
