introduction to microbes Flashcards
4 main types of microbes smallest to largest
virus bacteria fungi parasites
what size are viruses and bacteria?
10-8 to 10 -7 meters = viruses 10-6 to 10-5 = bacteria
what is the structure of bacteria?
nucleic with plasmids and loops of DNA lots of ribosomes pilli capsule, cell wall (peptidoglycan layer which helps it be resistant to peptidases bread down in the SI- it helps the bacteria survive in hostile places and is a big target for antibiotics) and cell membrane flagella
what is the difference between gram positive and gram negative? fucking essay but the lecture was shit so just got the workbook
positive = bacteria have thick, multilayered peptidoglycan cell wall that are exterior to cytoplasm membrane negative= more complex cell wall - it has 2 membranes (outer and inner- the inner is the cytoplasmic membrane) in between the 2 membranes is the periplasmic space thin peptidoglycan layer and cells therefore more susceptible to damage, the outermsmbrane has lipopolysaccharides- this is antigenic and can be used to identify strains. the lipid part of lipopolysaccharide is called lipid A and is embedded in the membrane and toxic to humans therefore is an endotoxin (not secret like an exotoxin)
what are some bacterial shapes?
coccus = circle cocci can be arranged in shapes e.g. busters and chains spirillus = spiral shaped batcteria bacillus /bacilli (plural) aka rods are cuboidal /cylinder
what are aerobes?
bacteria that can survive in the presence of oxygen obligate aerobes need oxygen to survive
what are anaerobes?
bacteria that can survive in the absence of oxygen obligate anaerobes need to be in oxygen free environment to survive unless able to from spores
how to name microbes?
genus then species names can be accompanied by an adjective describing growth or antimicrobial resistance and names can often change
medically important bacteria and in categories of cocci (-/+) and bacilli (-/+)
mechanisms of bacterial pathogeneis
(how they cause disease)
virulence factors= host entry, adhrence to host cell, invasiveness, iron sequestation
toxins= exo and endo
differnce between prokaryote and eukaryote?
what is fungi
A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as mushrooms. These organisms are classified as their own kingdom
what are parasites?
A parasite is an organism that lives on or in a host and gets its food from or at the expense of its host. Parasites can cause disease in humans.
main types:
protozoa (single celled) e.g. plasmodium flaciparum, giardia lamblia
heminths (worms, mulricellular)me.g. round worm, tape worm, flukes
what colour is a negative gram stain?
positive?
pink
violet
what is a gram stain
it is a test to differentiate 2 large groups of bacteria based on their cell wall contitiuents
+ = purple due to thick peptidoglycan cell wall
- = pink as the purple crystals are washed out when ethanol added
