Flashcards in Microbes Deck (49)
Microbes are microscopic organisms and particles.
Name four categories of microbes.
Bacteria, viruses, prions, and other organisms (such as fungi, multicellular parasites, and single-celled protistans.
Microbes that cause disease in humans
Give three positive uses of microbes.
Microbes can be used to make many foods, drugs, and they are important as decomposers to recycle nutrients.
Bacteria are single-celled, prokaryotic organisms. Almost all have a cell wall, and have DNA in a single chromosome - no nucleus. Some have plasmids. They have ribosomes, and reproduce by binary fission.
Accessory rings of DNA in bacterium
What does reproduction by binary fission result in?
Reproduction by binary fission results in 2 cells that are identical to the original cell.
What can be used to combat pathogenic bacteria?
Antibiotics can interfere with reproduction and survival of bacteria.
Name the three shapes of bacteria, and the words that describe the shape.
Sphere-shaped - "coccus"
Rod-shaped - "bacillus"
Curve-shaped - "spirillum"
Viruses are small, nonliving obligate parasites. They are acellular (not composed of cells). They all have an outer protein coat called a capsid and nucleic acid (RNA or DNA) inside. Some also have an envelope.
Why are viruses considered nonliving?
Viruses are considered nonliving because they cannot reproduce by themselves, and must reproduce inside of a host cell.
The outer protein coat on a virus
Do antibiotics work against viruses?
No, because antibiotics affect the reproduction of their target, and viruses don't reproduce on their own - they hijack host cells, which we don't want to target.
What does the damage from a virus depend on?
The damage from a virus depends on the efficiency of the immune system and the ability of the infected tissue to repair itself (e.g. common cold - respiratory track - versus polio - nerve cells)
Infectious protein particles. They occur when normal proteins change shape.
What do prions cause?
Prions cause degenerative disease of the nervous system, calcified plaque.
The study of diseases in populations
Diseases caused by pathogenic microbes, including bacteria, viruses, prions, fungi, parasites, and protozoans
More cases of the disease than expected in a certain area for a certain period.
If the epidemic is confined to a local area
A global epidemic
What genes comprise the H1N1 influenza virus?
Two genes from pig flu viruses, one from avian flu viruses, and one from human flu viruses
When was the first human to human transmission of H1N1 recorded in the US?
Phases 1-3 of a pandemic
Predominantly animal infection. Relatively few human infections.
Sustained human to human transmission.
The pandemic stage, in which there is widespread human infection.
Post Peak stage of Pandemics
There is a possibility of recurring events, but the worst is over.
Post Pandemic stages
The disease is at expected seasonal outbreak levels.
Roughly how many people in the US die of the flu and flu related complications?
About 36,000 people each years - predominantly elderly and very young.