Microbe
an unofficial group of all microscopic organisms (and viruses)
Microbes in relation to large organisms
microbes do everything large organisms do but don’t need skeletal, respiratory, digestive, or nervous systems since they don’t need it, and also exists almost everywhere including within other organisms
Bacteria genetic structure
usually single circular chromosome and multiple plasmids (circular dna for specific cellular functions)
Bacteria reproduction
binary fission (copy and divide) or lateral process (conjugation, transduction, transformation)
Conjugation
a bacterium transfers a copy of genes to another bacterium
Transduction
a bacteriophage (type of virus) infects and inserts viral dna into bacterium
Transformation
bacterium absorbs stray DNA, usually from dead bacteria
Chemoorganotrophs
consume organic molecules like carbohydrates, most bacteria that live in organisms are chemical organic feeders
Chemolithotrophs
consume inorganic molecules like ammonia, hydrogen sulfide, hydrogen, iron
Photoautotrophs
perform photosynthesis to convert carbon dioxide to glucose, these provided the world with oxygen 2.6 billion years ago
Probiotic therapy
treat infections by containing more benign/harmless bacteria than harmful
Pathogenic bacteria
disease causing, and some bacteria can become pathogenic under certain circumstances
Cause of STDs
caused by bacteria, viruses, protists, fungi, and arthropods
Antibiotic resistance
naturally some bacteria develop a resistance to antibiotics, so the goal is to take it as prescribed to kill as much of the pathogenic bacteria as possible without letting it replicate, and only take as needed
Potential of archaea
due to their extremophilic nature (though not all), archaea have potential to be used for extreme industrial purposes
Protists
single-celled, developed nucleus to become first eukaryotes, and integrated a bacterium to become the mitochondria (endosymbiosis)
Types of protists
animal-like (hunts and eats using phagocytosis), fungus-like (need carbon but no photosynthesis, spores to reproduce), plant-like (algae/seaweed, can be multicellular, photosynthesis)
Dangers of protists
protists can cause diseases in humans that cannot be treated with antibiotics or vaccines, e.g. parasitic protist Plasmodium causes malaria and is hard to fight off by the immune system since Plasmodium changes during its developmental stages and so immune system has a hard time identifying it
Virus
not a cell, non-living, no metabolism, just genetic material (DNA or RNA) in a protein container (capsid)
Viral replication
binds to host cell and injects DNA, DNA is replicated using host’s metabolism, mRNA is transcribed from DNA, mRNA makes new proteins host’s protein production, new copies of virus assembled from DNA and proteins
Differences between diseases caused by dna viruses vs rna viruses
dna viruses are easier to defend since replication processes correct mutations, but rna processes do not so viruses mutate more often
Virus species jumping
normally glycoproteins only allow viruses to infect 1 or a few related species, but sometimes for RNA viruses, if a virus from species A and a virus from species B are compatible with species C, species C may contract both viruses and mutate it to infect both A and B
Difficulties of HIV
a retrovirus or RNA containing virus that also has viral enzyme called reverse transcriptase, but since it is so error prone during replication, virtually every copy has a different mutation, and on top of that HIV also specifically targets white blood cells, so the body can’t fight it nor fight any other diseases anymore
