Flashcards in Bacteria Introduction Deck (8)
What colour do Gram positive bacteria stain?
What colour do Gram negative bacteria stain?
Differentiate Gram positive from negative in terms of membranes
Positive have a plasma membrane and a peptidoglycan
Negative have an additional periplasmic space and a lipopolysaccharide
Describe how to carry out Gram staining
Heat fixation of the sample to a glass slide
Add crystal violet and Gram's iodine (purple, complex formed)
Add acetone (negative decolourise - LPS dissolves)
Add secondary stain (colourless become red/pink)
Outline the range of flagellum types a bacterial cell may have
Monotrichous - one
Lopho - many from one point
Amphi - both sides
Peri - all over
What is meant by conjugation in term of bacteria?
Plasmid transfer from one bacterium to another
What 3 ways does genetic variation occur in bacteria?
Transformation (taken from dead)
Transduction (phage DNA infection)
Describe the 2 ways a bacteriophage is formed?
Lysogenic cycle - DNA injection and integration
Lytic cycle - no integration/replication of pathogenic/lysis