8.24.2022. part 2 Flashcards
What is thought to be the origin of life on our planet?
Microbial origin, under the sea in hypothermal vents
What is the difference between a microbe and a microorganism?
Microbe: general term to encompass 3 domains of life + acellular infectious agents
Microorganism: only refers to living things (3 domains)
What is the difference between infection and disease?
Infection: colonization of host
Disease: disorder of structure or function that is not simply a direct result of physical injury
Pathogenic microbes can be….
Cellular (3 domains) or acellular (A.I.A.)
What did Agostino Bassi do?
first to prove that a disease was caused by a microorganism
what was Agostino Bassi’s experiment?
finding that a fungus caused a disease in silkworms
What did Robert Koch do?
developed scientific method that established the microbial cause of disease
What were Koch’s postulates?
- microorganism must be found in sick animals, and not healthy ones
- must be able to isolate and grow microorganism
- microorganism must be able to make a healthy animal sick
- microorganism must be isolated from the newly sick animal and be identical to the one found in the originally sick animal
What are the revised Koch’s postulates for the 21st century?
- nucleic acid sequence is present in most cases
- present when you’re sick, absent when you’re not
- sequence-disease association is more likely to be causal (lung tissue more affected with covid)
- should be able to show presence of microbial sequence
- sequence based forms of evidence for microbial causation should be reproducible
What is the main challenge facing microbiology?
Hard to identify and grow microorganisms (we’ve only ID’d and grown 1%)
- either v harmful or v beneficial
- are mysterious diseases of microbial origin?
What size are prokaryotes?
0.1-5 microns
What size are eukaryotes
10-100 microns
What size are viruses?
0.02-0.4 microns
Do bacteria have DNA?
Yes, it’s just not enclosed in a membrane. It’s free floating. Or in a nucleoid
Do bacteria have a membrane-bound nucleus?
No
Are bacteria single celled, multi celled, or both?
Single celled
What molecule is unique to bacteria?
Where is it found?
Peptidoglycan
Rigid cell wall
What type of cell wall does bacteria have?
Rigid cell wall
How do bacteria multiply?
Binary fission
How do bacteria move?
Flagella
What is a PAMP?
What’s its significance?
pathogen-associated molecular pattern.
body says “that’s not mine” and starts an immune response.
How are archaea similar to bacteria?
Prokaryotes Similar shapes, sizes, and appearances Binary fission May move via flagella Rigid cell walls
How are archaea different than bacteria?
No peptidoglycan
Ribosomal RNA sequences are different
No known pathogens
Relate archaea to extremophiles
Many are extremophiles
Not all archaea are extremophiles, but most extremophiles are archaea
Are archaea more closely related to bacteria or eukarya?
Eukarya
