Introduction to Bacteria Flashcards
What are key differences between gram positive bacteria and gram negative bacteria cell wall
Gram+ larger peptidoglycan layer than Gram-ve
Gram neg contains outer membrane with lipopolysaccharides
What is the gram stain appearance of gram positive bacteria?
Purple
What is the gram stain appearance of gram negative bacteria?
Red
What is the gram stain appearance of cocci?
Spherical
What is the gram stain appearance of bacilli?
Rod shaped
What can you find on the cell surface of bacteria?
Plasma membrane
Penicillin binding sites
Peptidogylcan
Lipopolysaccharides (in gram negative bacteria)
What is the function of the murein / peptidoglycan?
Strength and shape
Counteracts the high osmotic pressure of the bacterial protoplast.
What is the response to lipopolysaccharides in animals and humans?
Strong immune response
What are frimbriae and what is the function?
A series of thread like projections used for adherence
What are spores?
Highly resistant dominant structures. A unit of asexual reproduction - Used in unfavourable conditions
How do bacteria replicate?
Binary fission - identical progeny
How is genetic variation increased in bacteria?
Spontaneous mutation
Transfer of DNA
What is a bacteriophage?
A virus which parasitizes a bacterium by infecting it and reproducing inside it.
How can bacteria be classified
Phenotypically:
Gram stain
Growth requirements
Genotypically:
Ribosomal RNA sequence analysis
Whole genome sequencing
How do you see an individually cultured bacteria?
Microscope Stain
How do you view a colony of individual bacteria?
Seen by eye, they are cultured on solid medium (agar)
What is used to identify strains within a species?
DNA typing techniques
