Terminology

Question 1

Gram positive stain

Answer 1

Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test.

Question 2

Gram negative stain

Answer 2

Do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation.[1] They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane.

Question 3

Anaerobe

Answer 3

Does not require oxygen for growth

Question 4

Facultative anaerobes

Answer 4

Do not require oxygen to grow but use oxygen if it is available

Question 5

Sterile

Answer 5

Absence of normal flora