Ch 15 Microbe Diversification

microbes

simplest but most successful organism on earth. Lives everywhere, eats almost anything, invisible to the naked eye. More of these on humans than cells in humans.

bacteria classification

capsule, cell wall, cell membrane, chromosome, plasmid (one or two), flagellum, ribosome

cocci

spherical bacteria

bacili

rod shaped bacteria

spirilla

spiral shaped bacteria

gram stain

dyes colorless bacteria, binds to the peptidoglycan layer within the cell wall

gram positive

appears purple, thus has multiple layers of peptidoglycan

gram negative

appears pink, thus has a thin layer of peptidoglycan. The microbe will be penicillin resistant

binary fission

the way bacteria replicate and divide

conjugation

bacteria transfers a copy of its DNA to another bacteria through direct contact

transduction

a virus containing DNA from previous host infects a new bacteria, passing on genetic information it may not have had

transformation

a bacteria can take up DNA (potentially some alleles it did not carry) from its surroundings

heterotroph

cannot create its own food

autotroph

is capable of creating its own food

chemoorganotrophs

feeds on organic molecules (carbon-based)

chemolithotrophs

feeds on inorganic molecules

photoautotrophs

use energy from sunlight to produce glucose (photosynthesis)

cynobacteria

modern cells that resemble the first photosynthetic organisms from 2.6 billion years ago. These created our oxygen-rich atmosphere we live in today.

aerobic bacteria

require oxygen for growth

anaerobic bacteria

do not require oxygen for growth

probiotic therapy

large number of benign bacteria are introduced to displace harmful bacteria. Includes lactobacillus, a good bacteria.

pathogenic bacteria

cause disease

sepsis

infection of bloodstream that leads to inflammation

septic arthritis

targets joints

toxic shock syndrome

staph bacteria get into bloodstream and produce toxins

endocarditis

bacteria affects areas in your heart valves

e. coli

group of bacteria that lives in the gut. Usually harmless, but some strains can cause infections and release toxins. Can come from contaminated foods, beverages, water, surfaces, etc.

archaea

thrive in habitats too extreme for most other organisms.

non-extremophile archaea

includes members of the human gut

protists

the first eukaryotes to develop organelles, and can be harmful

diatoms

microscopic, unicellular algae, make up a major portion of phytoplankton

malaria

caused by blood parasite protist called plasmodium. People with sickle-cell disease are immune to this.

viruses

are not cells, consists of a capsid, genetic material, plasma membrane, and glycoproteins

capsid

protein shell of a microbe

glycoproteins

on the surface of a virus; determines which host species and which tissues the virus can infect

virus replication

by hijacking a living cell. They insert their own genetic material into the host cell’s DNA, forcing it to make copies.

DNA viruses

have DNA sequences that remain stable over time due to error-checking mechanisms during DNA replication. Vaccines for these last for a lifetime.

RNA viruses

have no error-checking mechanisms, thus they continuously mutate and are more difficult to target with vaccines

antigenic drift

arises from the accumulation of mutations in the virus genes that code for virus-surface proteins that host antibodies recognize. This results in a new strain of virus that is not attacked by existing antibodies

antigenic shift

sudden change in antigenicity caused by the recombination of the genome, resulting in a new subtype of virus

antigen

foreign substances that trigger an immune response

antibody

proteins produced by the body to fight antigens

retrovirus

contains reverse transcriptase, which is error-prone, leading to frequent mutation