Chapter 1 Flashcards
Culture
a collection of cells that have been grown on or in a nutrient medium
Medium
a liquid or solid nutrient mixture containing all of the nutrients required for a microbe to grow
Cytoplasm
an aqueous mixture of macromolecules, small organic molecules, various inorganic molecules and ribosomes
Ribosomes
structures responsible for protein synthesis
eukarya
cells containing membrane-enclosed structures (organelles), ie. mitochondria, nucleus, chloroplasts
prokaryotic cells
lack a nucleus and typically lack organelles
All cells have:
a cytoplasmic membrane, ribosomes, and a genome
nucleoid
a mass of aggregated chromosome within a prokaryotic cell
plasmids
small circles of DNA not associated to that of the chromosome (in prokaryotic cells)
- contain non-essential genes, can be expelled, high energy cost to replicate during duplication
properties of ALL cells:
Metabolism, growth, evolution
metabolism
taking up nutrients, converting them to energy, expelling waste
catabolism
large molecules broken down into energy and smaller parts
anabolism
creation of macromolecules
properties of SOME cells:
differentiation, communication, horizontal DNA transfer, motility
differentiation
formation of modified cells specialized for growth, dispersal, or survival
horizontal gene transfer
exchange of genes between neighbouring cells, regardless of their species
rod-shaped cell
bacillus
spherical cell
coccus
spiral-shaped cell
spirillum
spirochetes
spiral shape, but flexible unlike the rigid spirillum
What enables Thiomargartia and Epulopiscium to be so large?
many copies of their genome throughout the cytoplasm
-prevents diffusional limitation between the genome and any region of the cytoplasm
(Thiomargarita also has a large vacuole in the middle of its cell)
3 domains to life
Archaea, Eukarya, Bacteria
Bacteria
prokaryotic cell structure. diverse appearance, size, and functions.
most are unicellular, but can be multicellular
80 phyla, 90% within 4
Archaea
Prokaryotic cell structure. 5 phyla. Thought to be extremophiles, but appear in nonextreme environments (ie. methanogens in animal guts)
- lack pathenogenic species
`1
Eukarya
Plants, animals, fungi
- phylogenetically young (Cambrian explosion ~600mya)
unicellular eukaryotes
- 2 Bya
Very unique and diverse in size, appearance, function, and physiology
Viruses
Not on the tree of life (not cellular)
- can replicate
- no metabolism (take over metabolism of host)
- genomes comprised of DNA or RNA, double or single-stranded
Thaurmarchaeota
archaea that inhabit soils and oceans
- important contributors to the nitrogen cycle
Five phyla of archaea
- Euryarchaeota
- Crenarchaeota
- Thaumarchaeota
- Nanoarchaeota
- Korarchaeota
90% of bacteria are found in these 4 phyla:
- Actinobacteria
- Firmicutes
- Proteobacteria
- Bacteroidetes
LUCA
Last Universal Common Ancestor
(~3.8 Bya)
Cyanobacteria
oxygen-producing phototroph bacteria
evolved ~2 Bya
how much of the earth’s lifetime was exclusively microbial?
80%
Nodules
structures in the roots of legumes where bacteria convert atmospheric nitrogen into ammonia (nitrogen fixation) - fertilizer for the plant
Ruminants
- lack enzymes for cellulose breakdown
- have a special chamber called the rumen where microbes digest and ferment cellulose
Industrial microbiology
wastewater treatment, bioremediation, biofilms, biotechnology, fermentation, biofuels
Biofuels
natural gas - methane, product of anaerobic metabolism of methanogenic Archaea
ethanol - produced by microbial fermentation of glucose from carbon-rich feedstocks (sugarcane, corn)
bioremediation
microbes are used to transform oil spills, solvents, pesticides, heavy metals, and other environmental toxins into nontoxic forms
wastewater treatment
microbes are used to treat waste water to be reused or returned to the environment
- cholera and typhoid can be removed
Van Leeuwenhoek
First person to see bacteria in 1676
Resolution
ability to distinguish two adjacent objects as distinct and separate
- low resolution value = high resolution power (see objects VERY close together)
Louis Pasteur
chemist who studied the chemistry of crystal formation during alcohol production
- led to discoveries in fermentation, spontaneous generation, pasteurization, and vaccine creation
Robert Koch
Created germ theory
- Koch’s postulates
- dyed tuberculosis cells
Koch’s postulates
- suspected pathogen must be present in the diseased organism and absent in healthy organisms
- suspected pathogen can be grown in pure culture
- pure culture can infect healthy organisms
- suspected pathogen can be reisolated and shown to be the same as the original
chemolithotrophy
metabolic process in which energy for growth is produced using inorganic chemical compounds
- defined by Winogradsky
enrichment culture technique
use culture media and selective incubation to selectively encourage growth of specific microbes
- developed by Martinus Beijerinck
rRNA are good candidates for phylogenetic analysis because they were:
- present in all cells
- functionally constant
- highly conserved in their nucleic acid sequence
- of adequate length to provide a deep view of evolutionary relationships
euchromatin
loosely packaged, lighter DNA
Eukarya
Heterochromatin
tightly packaged, darker DNA
Eukarya
Nucleolar organizing center
site of active transcription, rRNA and other machinery
Eukarya
Histones
proteins that package DNA into chromosomes
Eukarya
