Microbiology Diversity Flashcards
Humans have over ___ trillion microbes residing in and on the body. Microbes outnumber human cells in what ratio?
100
3:1
What two types of bacteria does gram staining categorize into?
Gram Positive - Bacteria have much thicker cell walls, holding the dye in better (purple)
Gram Negative - Bacteria have much thinner cell walls, allowing the dye to leak (pink)
Using the MacConkey agar, does E.coli produce lactose? is it gram negative or positive?
It does produce lactose as it is red
It is gram negative
Branches shift depending on the genomes sequences used
tree of life
Gene sequencing is the main method used today to determines. Before it was mutations
relatedness between organisms
The most common fungi is ______
yeast
coccus means
spherical
Why are archaea hard to study
They leave in extreme places, are small, and are hard to find
We have never found an archaea that casues ______ in humans
disease
Mycology is the study of what?
Fungi
Hyphae and chitin makes fungi
distinct
A virus is an infectios agent that has RNA or DNA as it’s core
ds
How many bacteria can be in one teaspoon of fertile soil?
100 million to 1 billion
Microbes have also been found through the Earth’s _________, up to _ miles above ground
troposphere, 9
How can bacteria in the sky influence the weather?
Nucleating ice crystal formations and forming ran drops that eventually bring the bacteria back down to the ground
How do microbes in Antarctica stay alive?
They scavenge hydrogen, carbon monoxide, and carbon dioxide form the air
Researchers found almost ______ different bacteria living under 800 meters of ice in the west Antarctic
4000
Marine microbes make up to __ to __% of the ocean’s biomass
70, 90
______ _______ perform most of the world’s oxygen and also aid the in global cycling of carbon, nitrogen, phosphorous, and other nutrients
Marine microbes
Where can most microbes in humans be found?
Skin, hair, respiratory system, and digestive tract
How can microbes aid or harm humans?
Some help with digestion
Some causes lung infections or creates plaque on teeth
Where can microbes be found?
Almost every environment on Earth
Microbes can be both ______ and _________
prokaryotes, eukaryotes
Which kingdoms have microbes?
Bacteria, archaea, protists, fungi, and sometimes viruses
There are also some microscopic animals
What 3 categories do we use to categorize microbes?
Physical Characteristics
Chemical Characteristics
Genetic Phylogeny showing relationships between organisms
Microscopy enables ________ __________ of microbes
visual identification
What is Gram staining?
A technique to visualize bacteria
What are examples of physical characteristics that can be identified with microscopes?
prokaryote vs eukaryote
size, shape, color, cell wall characteristics
immobile vs mobile
Describe how the petri dish and agar came to be?
- Scientists tried to cultivate microbes on various substrates like potatoes, egg white, and meat. These lacked the right nutrients
- Robert Koch discovered that aqueous humor from rabbit eye was effective, but hard to get
- Koch tried to use gelatin, but that liquefies at 37C
- His assistant Angelina Hesse discovered that agar was effective
- His other assistant Julius Petri designed a shallow, covered dish for the agar
What is a colony?
A collection of multiple identical organisms
What are some physical characteristics of colonies?
shape, elevation, margin, surface features, opacity, pigmentation
What are some environmental conditions that affect microbe growth?
Temperature, surface material, humidity, PH, and the composition of nutrients
How can we grow specific microbes?
Carefully controlling growth conditions for the desired microbe
What are some examples of chemical characteristics that can be used to identify microbes?
Autotrophic (only need CO2) vs heterotrophic (need organic carbon)
Chemical requirements for life processes
Resistance to antibiotics, etc.
How does phylogenetic analysis work? Who proposed this, and when?
It works by comparing sequences of genes or proteins to identify genetic relationships between organisms
Proposed by Emile Zuckerkandl and Linus Pauling in 1965
When and who classified archaea separately from bacteria due to differences in their rRNA genes?
1977 - Carl Woese and George E. Fox
Carl Woese, Otto Kandler and Mark Wheelis later proposed to reclassify organisms from the 2 empire system to the _______ ______ system of life
3 domain
From Prokaryotes and Eukaryotes to Bacteria, Archaea, and Eukarya
Describe bacteria
Single celled prokaryotic microbes
Range of 0.5 to 5 um in length
Distinguished by cell wall, their shape, and genetic makeup
Can be mobile or immobile. (The presence of flagella and/or cilia help distinguish bacteria)
Rank the 3 domains of life from most diverse to least diverse
Bacteria
Eukarya
Archaea
Describe Archaea
- Single celled prokaryotes (0.1 to 15 um in diameter)
- Generally similar in size and shape to bacteria (but also includes shapes like squares)
- First discovered in extreme environments (extremophiles) - Salt lakes, pH 0 hot springs, 122C ocean thermal vents
- Can also live in more mild conditions (mesophiles)
- More related to Eukarya than bacteria (but endosymbiotic theory suggests otherwise)
- Most abundant ammonia-oxidizing organisms in soils and accounts for 20% of the microbes present in picoplankton
- Remove 10-25% of global methane emissions
- Nanoarchaea are the smallest known living cell (1/100 size of E. Coli) with the smallest genome (112 kilobases)
Describe Kingdom Fungi
- Christiaan Hendrik Persoon considered the founder of modern mycology
- Includes yeast, mold and mushrooms
- Are heterotrophs
- Have chitin in their cell walls
- Grows hyphae underground. (2-10 um diameter, several cm length)
- The mushroom is the reproductive structure containing spores in its gills (which germinate to make more hyphae
- Oregon fungal colony is 2400 years old and span 2200 acres
Describe protists
- Mostly unicellular, but some are multicellular
- 3 general categories: animal like heterotrophs (amoeba), plant like autotrophs (green algae), fungus like autotrophs (slime mold)
Describe Algae
- Variety of shapes (spherical, rod, club, spindle)
- Some motile
- Contains chlorophyll
- Can be unicellular and microscopic or multicellular and up to 120 m
- Some organized as filaments of cells attached end to end
- Occur in colonies
Describe viruses
- Small infection agent that can only reproduce itself inside the cells of a living host. (animals, plants, microbes)
- First one studied was tobacco mosaic virus
- 1887, Dmitri Ivanovsky discovered that the disease was caused by extremely small infection agents, capable of passing through filters
- 1898, Martinus Beijerinck replicated above results and called it a virus
- In the same year, Friedrich Loeffler and Paul Frosch identified the first animal virus
- Early 20th century, Frederick Twort discovered bacteriophages, viruses that infect bacteria
- Origin unclear because no fossil records. Evidence based on molecular analyses of the viral genomes and also viral genetic material that integrates into the reproductive cells of its host
- Could pre-date divergence of life into 3 domains
