Topic 3 Flashcards
Staphylococcus Epidermidis is a type of
Prokaryote
The vast majority of bacteria are
Harmless or beneficial to us
What is the name for Anthrax
Bacillus Anthracis
Give examples of diseases that are caused by bacteria
Lyme Disease TB Strep Throat Gonorrhea Syphilis
What is a capsule?
A thick layer of protein. It is more dangerous to use as humans, it is harder to destroy, it makes the cells more slippery
Describe the nucleus region in a bacteria
They lack a nucleus but have a nucleoid region
Prokaryotes have small..
- Genomes
- One big ring in nucleoid region = chromosome
- Smaller rings = plasmids
How are ribosomes different in bacteria than in Eukaryotes?
They are smaller and have a different makeup than the one’s in Eukaryotes
- different protein and RNA content
- the genes for these rRNAs are often used for classification
What is a chromosome?
A single loop of DNA
What are plasmids?
Extra small loops of DNA
What are traits coded for by plasmid genes? (Slide 13)
ABX resistance, toxin production, ABX synthesis
What is increased virulence?
More likely to cause damage, can spread more readily
What is the defining characteristic of bacteria?
There is no nucleus
What is the surface area of bacteria?
Large so enzymes can attach to it
Can bacteria have internal membranes?
Yes
How do Prokaryotes divide?
Binary fission = splitting
It takes roughly 20 minutes
How do Eukaryotes divide?
Mitosis (there are 4 steps)
It takes roughly a day
Historically, how were Prokaryotes classified?
- Microscopic observations
- shape
- response to stains - Biochemical characteristics (and growth conditions)
Recently, how were Prokaryotes classified?
Compare DNA sequences (% similarity)
- Typically use the genes for rRNA
- For clinical analysis, we can identify bacteria “quickly” using PCR
What is PCR?
Polymerase Chain Reaction. It is a way to amplify DNA without cells
What are the shapes of prokaryotes?
- Coccus
- Bacillus
- Vibrio
- Spirillum
What are the possible arrangements of prokaryotes?
Diplococci, Streptococci
Define diplococci and give an example
When prokaryotes go through binary fussion, some spherical cells do not split
Ex: Streptococcus pneumoniae
Define Stretococci and give an example
When they divide they do not attach, they form a long chain
Ex: Stretococcus penumoniae
How do Spirillum cells move around?
Freely, they do not bunch up
What is the peptidoglycan structure used for?
It is used for support in bacterial cell walls (the peptide crosslinks provide strength to the cell wall and enable the bacterium to resist osmotic lysis)
What medication weakens peptidoglycan cell walls?
Penicillin
What colour do gram (-) stain?
Pink/Red
What colour do gram (+) stain?
Purple/Blue
Describe the structure of a gram-negative cell wall?
Lipopolysaccharides
Outer Membrane
Peptidoglycan
Plasma Membrane
Describe the periplasm
The region between the membranes. It contains enzymes which can breakdown toxins and ABX
Describe lipopolysaccharide (LPS)
A unique lipid/carbohydrate found on the outer layer of the outer membrane
- An endotoxin (may can an immune or toxic reaction)