intro to microbiology Flashcards
Bacteria are prokaryotes. Describe the features of a bacteria
Bacteria have:
- a peptidoglycan wall
- no nucleus, just free floating DNA or plasmids (circular DNA)
- no defined organelles
What is the purpose of the bacterial peptidoglycan cell wall?
Protection from the host; it protects the bacterium from being phagocytosed.
How do bacteria replicate?
Bacteria replicate via binary fission, which involves the pinching of the bacterial cell wall into two.
What is the gram stain test used for?
Classification- To distinguish certain types of bacteria from others.
What are gram positive bacteria?
These are bacteria that have a very thick peptidoglycan wall, which absorbs a lot of gram stain. This makes it gram positive and it glows purple.
What are gram negative bacteria?
These bacteria have very thin peptidoglycan walls which don’t absorb much gram stain. Thus, they are considered to be gram negative, and glow red, not purple.
What shape is a ‘baccilus’ bacteria?
It is rod-shaped
What shape is a ‘spirillum’ bacteria?
It is wriggly, snake-like or helical in shape.
what is an opportunistic bacteria?
A bacterial strain that is normally harmless, except for when the individual’s immune system is compromised. Then the bacteria become pathogenic.
Which is smaller- a virus or a bacterium?
A virus is smaller than a bacterium
Why is a virus considered to be a true parasite?
Because they rely on host cells for their replication, and destroy the host cell in the process.
Describe the key features of a virus.
Viruses have:
- a caspid, a container that stores its genetic information
- either RNA or DNA genome.
Fungi are eukaryotes. Describe their key features
Fungi have:
- Defined organelles
- a nucleus with DNA in it.
How do fungi reproduce?
By spores, that float around and land on a suitable host.
What is a mycoses?
A fungal infection.
