Mod 1: characteristics of Microorganisms Flashcards
Microoganisms…
small, usually unicellular, also called germs, microbes and bugs
Groups of microorganisms
protozoa, fungi, bacteria, viruses
Protoza
unicellular, move with flagella
Fungi
primitive plants, yeasts and molds
Bacteria
unicellular, no organized nucleus cell wall
Viruses
a bit of DNA or RNA surrounded by protein coat and sometimes lipid coat, grow only in other living cells
Sizes of Microbes
measured in micrometres (um) most bacteria is about 1 um
Shaes of bacteria
Cocci (round), rods/ bacilli (rectangular) , spirilla (spiral, curved)
Gram Reaction
Dark blue = gram positive
Red = gram negative
Why gram reactions are important
identify bacteraia (shape and reaction)
effectiveness of antibodies
effectiveness of disinfectants
Bacterial growth
reproduce by binary fission
generation time = 15-30 mins for rapidly growing bacteria under ideal conditions
Bacteria grow on a
media dish
Colony means
visible mass of bacteria that forms on surface of solid culture media (18-24 hrs to form 1 original cell) each colony is a clone
Bacterial Growth Curve
4 phases: LAG, LOG, Stationary, Death
LAG means
adapting to new enviornment
LOG means
max reproduction
Stationary means
no change in #
Growth Curve with infection
no symptoms (incubation phase), full blown symptoms (acute phase), no better; no worse, on the mend, convalescence
Viral Characteristics
metabolically inert- can multiply only in living host cells
contain DNA or RNA not both
have protein coat
Multiplication of viruses
1) attachment to host cell membrane
2) penetration
3) viral nuclei acid -> nucleus: takes command of host cell and directs synthesis of new viral components
4) synthesis of viral components
- nucleic acid (in nucleus)
- protein coat (cytoplasm)
5) assembly of viral components
6) release from host cell
Effects of viruses on host cell
Host cell dies, host cell may be transformed into tumor cell
Controls over viruses
antibiotics NO effect
antiviral drugs
more and more ntivirals being developed. problem is that viruses are inside host cells- have to develop drugs which will destroy viruses without destroying host cell
