Lecture 23 - Bacteria: Prokaryotic Pathogens Flashcards
Do bacteria maintain structural integrity during replication? What about viruses?
Bacteria do, viruses do not.
Why are bacteria generally not obligate parasites?
Because they make ATP and protein themselves.
Which bacteria ARE obligate parasites?
Chlamydia and infectious blindness (trachoma).
What is the cell size of a bacterium?
0.5-3µm by 0.5µm
How many genes does the average bacterium have? Give an example of a bacterium and its number of genes.
Normally a bacterium will have 4000 genes.
For example Salmonella has 4500 genes.
Do bacteria have organelles?
No
Do bacteria have cell membranes?
Yes
What is the cytoskeleton of a bacterium like?
Rudimentary
Do bacteria have cell walls and what are they like?
Yes, they are complex.
How do bacteria move?
Vi a flagella polymer that rotates (helical propellers)
How do bacteria divide?
Binary fission.
How do bacteria sexually reproduce?
There is no meiosis, but there is DNA transfer.
What is the genome of a bacterium like?
Haploid, usually single and circular.
Other components are plasmids and bacteriophages.
What is the mRNA of bacteria like?
Polycistronic (co-linear genes), unstable (length of survival measured in minutes).
What is the regulation of proteins like in bacteria?
Mostly transcription initiation.
What is the difference between the terms ‘pathogenic’ and ‘virulent’?
Being pathogenic is the intrinsic nature of a bacteria, whereas bacteria can be more or less virulent - it is a term that can be compared.
What is MreB? What does MreB do in a bacteria? What does the deletion of MreB lead to?
MreB is a homologue of actin, which controls the cell shape of bacteria. Deletion of MreB leads to the coccus shape that bacteria can have.
Which shapes do pathogenic bacteria usually have?
Coccus, curved rods or spiral.
Which pathogenic bacteria adopt the coccus shape?
Staphylococcus, Streptococcus, Enterococcus.
Which pathogenic bacterium adopts the ‘curved rod’ shape?
Vibrio cholerae.
Which pathogenic bacteria are spirally shaped?
Treponema (syphillis) and Helicobacter (gastric ulcers).
Which bacteria produce dormant endospores to survive in the environment?
Clostridium tetani (tetanus), C. perfringens (gas gangrene, food poisoning), C. botulinum (‘botulism’ food poisoning) and Bacillus anthrax (anthrax).
Which bacteria was discovered first and why?
Anthrax because it is the largest.
What is the difference between Gram-negative and gram-positive bacteria?
Gram positive bacteria have a thicker peptidoglycan wall whereas gram negative bacteria have an extra (outer) membrane.
