Week 3 Flashcards
(69 cards)
1
Q
What are microorganisms?
A
- the oldest form of life on Earth
- They have evolved to preform critical functions that sustain the biosphere
2
Q
How old is the Earth?
A
4.6 billion years old
3
Q
when did microbial cells first appear?
A
between 3.8 and 4.3 billion years ago
4
Q
During the first 2 billion years of earth…
A
its atmosphere was anoxic (O2 was absent), and only nitrogen carbon dioxide and a few other gases were present
5
Q
What was the Earth’s origin like
A
sterile and anoxic
6
Q
what was present 3.8 billion years ago?
A
bacteria and archaea
7
Q
what caused Earth to become oxygenated over time
A
- The evolution of phototrophic bacteria called cyanobacteria
8
Q
When were current levels of atmospheric O2 achieved?
A
500-800 million years ago
9
Q
phototrophic microorganisms
A
organisms that harvest energy from sunlight
10
Q
When did phototrophic microorganisms evolve?
A
within 1 billion years of the formation of Earth
11
Q
what were the first phototrophs?
A
anoxygenic
12
Q
Cyanobacteria
A
oxygen-producing phototrophs
13
Q
When did cyanobacteria evolve
A
nearly a billion years later and began the slow process of oxygenating Earth’s atmosphere
14
Q
Microbial Mats
A
Microbial Mats: The structures that these early phototrophs lived in structures and are still found on Earth today
15
Q
Multicellular Life:
A
Evolved after the oxygenation of Earth’s atmosphere, culminating in the plants and animals we know today
16
Q
How long have plants and animals existed?
A
about half a billion years
17
Q
How much of life’s history was exclusively microbial?
A
80%
18
Q
What can Earth be considered?
A
A microbial planet
19
Q
Three major lineages of microbial cells:
A
- The Bacteria
- The Archaea
- The Eukarya
20
Q
How many genes are present in cells of all 3 domains
A
approx 60 genes
21
Q
- last universal common ancestor (LUCA):
A
- examination of the common genes reveals that all three domain have descended from a common ancestor
- Microorganisms fill every habitable environment on Earth
22
Q
what constitutes a major fraction of global biomass?
A
Microbials
23
Q
How many stars are there in space?
A
7x10 to the power of 22 stars
24
Q
How many microbial cells are there on Earth?
A
2x10 to the power of 30 microbial cells
25
How much nitrogen and phosphorus are present within microbial cells
almost 4 times that in all plant and animal cells combined
26
Extremophiles
properties define the physiochemical limits to life
27
Microbes are abundant in:
* volcanic hot springs
* glaciers
* ice-covered regions
* high-salt environments
* extremely acidic or alkaline habitats
* deep in the sea
* deep in the earth at extremely high pressure
28
Metabolic activities
metabolic activities of microorganisms can see the change the habitats which they live, both chemically and physically, and these changes can affect other organisms
29
How can we predict and minimize the effects of human activity on the biosphere that sustains us?
only by understanding microorganisms and microbiology
30
why are microorganisms contributions easy to overlook?
because of their small sizes
31
How many microbial genes are present for every human gene?
more than 200 microbial genes
32
what do microbial genes do
provide benefits and services that are essential to human health
33
What are microbes important to?
myriad issues of global importance to humans including climate change, agricultural productivity, and even energy policy
34
Microbiologists study
* microorganisms function
* Advanced human health and welfare
* in food and agriculture
* produce valuable human products
* generate energy
* clean up the environment
35
Microbio has fuelled advances in:
* medicine such as vaccination and antibiotic therapy
* advances in engineering such as water and wastewater treatment
* advances in food safety such as pasteurization
* a better understanding of how microorganisms are transmitted
36
Agriculture
* the cycling of nitrogen, sulfur, and carbon
37
Legumes
* a diverse family of plants that include major crop species such as soybeans, peas, and lentils, among others
38
What do legumes live in close association with?
* legumes live in close association with bacteria that form structures called nodules on their roots
39
What does the bacteria that is in close relations with leagues do?
* these bacteria convert atmospheric nitrogen into ammonia through the process of nitrogen fixation. is the major nutrient found in fertilizer
40
what does the rumen contain
dense and diverse community of symbiotic microorganisms that digest and ferment cellulose
41
What other things are ruminants
* many domesticated and wild herbivorous mammals - including deer, bison, camels, giraffes, and goats
42
what does the GI tract rely on
* rely on microbial partners for our nutrition
43
how many microbial cells foes the colon contain
* the colon contains about 10 to the power of 11 microbial cells per gram of colonic contents
44
why do humans rely on our gut microbiome for this purpose
* human enzymes lack the ability to break down complex carbohydrates (which can represent 10-30% of food energy)
45
where are microbial cells low?
* low in the very acidic (pH 2) stomach (about per gram)
46
where do microbial cells increase
* increase to about per gram near the end of the small intestine (pH 4-5)
47
Where do maximal microbial cells live?
* Reach maximal numbers in the colon (pH 7)
48
What do microbial cells do?
* in the digestion of complex carbohydrates
* synthesize vitamins and other nutrients essential to host nutrition
* The gut microbiome develops from birth, but it can change over time with the human host
49
What food are microorganisms present in?
* food spoilage
* foodborne disease
* improve food safety and preserve foods
* for baking
* for the production of alcoholic beverages
50
what is a large focus in the food industry
* microbial food safety and prevention of food spoilage is a major focus of the food industry and a major cause of economic loss every year
51
what foods have microbial production
* microbial production of lactic acid in cheeses, yogurt, and buttermilk are all produced by microbial fermentation of dairy products
52
what does microbial lactic acid do?
improves the shelf life of fermented products and prevent the growth of foodborne pathogens
53
Lactic acid definition
* Lactic acid - producing bacteria are used to produce a variety of sour-tasting foods, including sauerkraut, kimchi, pickles, and even certain sausages even the production of chocolate and coffee rely on microbial fermentation
54
Industrial microbiology
* the use of microorganisms as tools for major industries such as pharmaceuticals and brewing
55
bioreactors called fermentors make large amounts of products:
- antibiotics
- enzymes
- alcohol
- certain other chemicals
56
Biotechnology
* employs genetically engineered microorganisms to synthesize products of high commercial value, such as insulin or other human proteins, usually on a small scale
57
Natural gas (methane)
product of the anerobic metabolism of methanogenic Archaea
58
what alcohol is a major fuel supplement
ethyl alchohol (ethanol) major fuel supplement, which microbial fermentation of glucose obtained from carbon-rich feedstocks such as sugarcane, corn, or rapidly growing grasses
59
what should biofuels do?
* biofuels should help cool our planet and are one facet of the "green revolution" many countries support today
60
Wastewater treatment
waterborne diseases such as cholera and typhoid (major killer before the blossoming of microbiology
61
Bioremediation: microbes can be used to clean up industrial pollution into nontoxic forms:
* Spilled oil
* Solvents
* Pesticides
* Heavy metals
* Other environmentally toxic pollutants
62
Where are biofilms:
* in pipes and drains can cause fouling
* blockages in factory settings and pipelines
* in sewers
* in water distribution systems
* ship's hulls can caused marked reductions in speed and efficiency
* in tanks that store oil and fuel, leading to spoilage of these products
* on implanted medical devices can cause infections that are extremely difficult to treat
63
Who is Robert Hooke
* english mathematician and natural historian
64
What did Robert Hooke write?
his famous Micrographia, the first book devoted to microscopic observations
Hooke illustrated many microscopic images including the fruiting structures of molds this was the first known description of microorganisms
65
Microscopy
* bright-field
* phase-contrast
* differential interference contrast
* dark-field
* Fluorescence
66
Numerical Aperture
* The limit of resolution for a light microscope is a function of the wavelength of light used and the light-gathering ability of the objective lens
67
What is there a correlation between
between the magnification of a lens and its numerical aperture
68
lenses with higher magnification....
typically have higher numerical apertures
69
Oil immersion lenses
Immersion oil increases the light-gathering ability of a lens; that is, it increases the amount of light that is collected and viewed by the lens.
