colony morphology

Which of the following organisms is known for producing swarming colonies on agar plates?

• a) Escherichia coli

• b) Proteus mirabilis

• c) Pseudomonas aeruginosa

• d) Staphylococcus aureus

What is the characteristic appearance of Pseudomonas aeruginosa colonies on nutrient agar?

• a) Pink with a clear zone

• b) Greenish metallic sheen

• c) Yellow with a fruity odor

• d) White and smooth

What does the presence of mucoid colonies indicate?

• a) The organism produces a capsule or exopolysaccharide

• b) The organism is a strict anaerobe

• c) The organism is gram-negative

• d) The organism produces spores

Which of the following organisms exhibits black colonies with a brown halo on Tinsdale agar?

• a) Corynebacterium diphtheriae

• b) Streptococcus pneumoniae

• c) Bacillus anthracis

• d) Escherichia coli

What type of growth pattern would be expected from an obligate aerobe in thioglycollate broth?

• a) Growth throughout the broth

• b) Growth only at the bottom of the broth

• c) Growth only at the top of the broth

• d) Growth in a uniform cloud throughout the broth

Which of the following bacteria is an obligate anaerobe?

• a) Escherichia coli

• b) Clostridium botulinum

• c) Pseudomonas aeruginosa

• d) Staphylococcus aureus

Which bacteria species is known for exhibiting a "greenish metallic sheen" on agar plates?

• a) Streptococcus pneumoniae

• b) Pseudomonas aeruginosa

• c) Klebsiella pneumoniae

• d) Neisseria gonorrhoeae

Which type of bacteria can grow both with and without oxygen, but prefers oxygen for metabolism?

• a) Aerotolerant anaerobes

• b) Obligate anaerobes

• c) Obligate aerobes

• d) Facultative anaerobes

What is the defining feature of aerotolerant anaerobes?

• a) They can only grow in the presence of oxygen

• b) They cannot tolerate oxygen at all

• c) They do not use oxygen for growth but can tolerate its presence

• d) They require a very low concentration of oxygen

Which of the following is true about thioglycollate broth?

• a) It is used to promote aerobic growth

• b) It creates an oxygen gradient that helps determine the oxygen requirements of organisms

• c) It is selective for gram-negative organisms

• d) It does not allow any growth of anaerobic organisms