Microbiology Exam 1 Questions with Correct Answers

Microbiology Exam 1


Identify 3 components of both gram positive and negative bacteria. - Answer--Cell wall

-Capsule

-Plasma cell membrane



Compare/contrast gram (+) and gram (-) bacteria - Answer-Gram (+)

1. thick peptidoglycan

2. small periplasmic space

3. Teichoic acid



Gram (-)

1. THIN peptidoglycan

2. LPS

3. Porins

4. Large periplasmic space



Plasmids carry genes for? - Answer-1. Antibiotic resistance

2. Resistance to heavy metals (Hg, Ag)

3. Resistance to UV light

4. Pili

5. Exotoxins

,Bacterial shapes: cocci - Answer-- diplococci (pair)

- streptococci

- tetrad (4)

- staphylococci

- Sarcina (cube of 8)



Bacterial shapes: Rods (Bacilli) - Answer--chain of bacilli

-flagellate rods

-spore former



Bacterial shapes: Spirals - Answer--Vibrios

-Spirilla

-Spirochaetes



The shape of a bacterium is determined by its _____. - Answer-rigid cell wall



Smallest and largest bacteria - Answer-Smallest:

Mycoplasma



Largest: Bacillus anthracis



Bacteria is a prokaryote with the following characteristics : ______ - Answer--no nucleus or membrane-
bound organelles

-chromosomes and plasmids freely float in cytoplasm



Function of cells wall - Answer-• Provides structural

, support

• Made of peptidoglycan

(polysaccharide)



Function of capsule - Answer-Sticky outer layer

for protection and

attachment



Function of plasma cell membrane - Answer-• Directs what enters

and exits

• Phospholipid bilayer



Differences in cell walls gram (-) and (+) - Answer-



Gram positive bacteria structure - Answer-• Inner plasma cell membrane (phospholipid bilayer)

• Thick 'peptidoglycan' cell wall

• Outer Capsule



Gram negative bacteria structure - Answer-• Inner plasma cell membrane

(phospholipid bilayer)

• Thin 'peptidoglycan' cell wall

• Another outer plasma cell

membrane (phospholipid

bilayer - 'lipopolysaccharides')

• Outer Capsule