Microorganisms and the biosphere Flashcards
When was the earth anoxic?
During the first 2 billion years of Earth’s existence, its atmosphere was anoxic (O2 was absent), and only nitrogen carbon dioxide and a few other gases were present
How old is the earth?
4.6 billion years old
When were bacteria and archea found?
Cellular life, in the form of Bacteria and Archaea, was present on Earth by 3.8 billion years ago (bya).
Cyanobacteria relevance
The evolution of phototrophic bacteria called Cyanobacteria caused Earth’s atmosphere to become oxygenated over time
Phototrophic microorganisms
Organisms that harvest energy from sunlight
Cyanobacteria—oxygen-producing (oxygenic) phototrophs
Cyanobacteria evolved nearly a billion years later and began the slow process of oxygenating Earth’s atmosphere.
Microbial mats
the structures that these early phototrophs lived in structures and are still found on Earth today
Multicellular life evolution
evolved after the oxygenation of Earth’s atmosphere, culminating in the plants and animals we know today.
Existence of plants and animals on earth
only existed for about half a billion years.
Three major lineages of microbial cells
the Bacteria
the Archaea
the Eukarya
Last universal common ancestor (LUCA):
Examination of the common genes reveals that all three domains have descended from a common ancestor
Microbial Activity in the Biosphere
The total amount of carbon present in all microbial cells is a significant fraction of Earth’s biomass.
Total amount of nitrogen and phosphorus within microbial cells is almost four times that in all plant and animal cells combined.
A major fraction of the total DNA in the biosphere (about 31%), and their genetic diversity far exceeds that of plants and animals.
Microbial Abundance in the Biosphere
Constitute a major fraction of global biomass.
The key reservoirs of nutrients essential for life.
There are an estimated 2x1030 microbial cells on Earth
To put this number in context, the universe, in all its vast extent, is estimated to contain merely 7x1022 stars.
extremophiles
Such microorganisms are called extremophiles and their properties define the physiochemical limits to life
e.g.
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
dead zone
Manipulate the microbial life which determines the ecosystem which results in dead zones e.g. putting organic waste in the ocean which kills the microbial life and then there is NO life
Biosphere predeiciton
Only by understanding microorganisms and microbiology can we predict and minimize the effects of human activity on the biosphere that sustains us.
Microbes in the body
More than 200 microbial genes are present for every human gene.
Microbes determine your cravings, socialisatoins, mood, personality
MICROBES ARE KEEPING US ALIVE
Microbiologists study
Microorganisms function
Advanced human health and welfare
In food and agriculture
Produce valuable human products
Generate energy
Clean up the environment.
Vaccination
process of training your body/cells for right and adequate immune response
e.g. troops fighting enemies. Troops can regonise eachother because of uniforms “antigens”, in order to differentiate from enemies: they have different uniforms “antigens”. To make troops know what to look for in enemy, sample enemy is shown in front of them so troops can regonise them. This is what happens in a vaccine. Little bit of vaccine is shown so body can recognise it and differentiate it in the future.
- Food and water are the easiest way for microorganisms to get into the body.
Disease:
any change or alteration in the normal regulation of our metabolism or cellular structure that causes some damage
Infection
starts replication process but no damage- no symptoms- once symptoms present it is disease
Antibiotic
Rumen:
Microorgansims that are responsible for the enzymatic action of breaking down cellulose that cannot be broken down by animal cells
e.g. cows have seconf stomach that contains enzymes which cleave the plant proteins so they can be absorbed and utilized
Where are microorganisms most prevelent in gut?
Most of these organisms cannot survive in the stomach acid so the number increases in small intestine but most are in the colon as the pH is 7 and this is a more liveable environment for these microorganisms
Vitamins/nutritents sythensised: e.g. Vit B12, short chain fatty acids
Do humans have a rumen?
Humans do not have a rumen- the gut contains microorganisms that have enzymes that can break down/cleave the plants so we can utilize their nutritents
Do all food spoilage lead to illness
Food spoilage is not neccessaryily the same microorganisms that cause disease
Some microorganisms sit on the food without affecting it, but produce toxins that leads to poinsing when we ingest them
Characteristics for pathogenic microbial growth:
Optimal temp for growth is 37
Optimal pH is 7
What are the benefits of fermentation?
The products of microbial fermentation affect the flavor and taste of foods and can prevent spoilage as well as the growth of deleterious organisms.
Microbial production of lactic acid in cheeses, yogurt, and buttermilk are all produced by microbial fermentation of dairy products.
Microbial lactic acid improves the shelf life of fermented products and prevents the growth of foodborne pathogens.
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.
The fermentative activities of yeast are essential
for baking (by generating carbon dioxide to raise the dough)
for the production of alcoholic beverages (by generating alcohol)
Fermentation
Form of anerobic catabolism/metabolism
When micro-organism convert organic substances into energy
what are the sources of fermentation?
Major fermentations in various fermented foods. It is the fermentation product (ethanol, or lactic, propionic, or acetic acids) that both preserves the food and renders in it a characteristic flavor.
Industrial Microbiology
The use of microorganisms as tools for major industries such as pharmaceuticals and brewing.
Bioreactors called fermentors make large amounts of products
Antibiotics
Enzymes
Alcohol
Certain other chemicals
Biotechnology
Employs genetically engineered microorganisms to synthesize products of high commercial value, such as insulin or other human proteins, usually on a small scale.
Biofuels
Natural gas (methane, ) is a product of the anaerobic metabolism of methanogenic Archaea.
Ethyl alcohol (ethanol) is a major fuel supplement, which
microbial fermentation of glucose obtained from carbon-rich feedstocks such as sugarcane, corn, or rapidly growing grasses.
Biofuels should help cool our planet and are one facet of the “green revolution” many countries support today.
Wastewater treatment:
Waterborne diseases such as cholera and typhoid (major killers before the blossoming of microbiology
Bioremediation:
Microbes can be used to clean up industrial pollution into nontoxic forms
spilled oil
Solvents
Pesticides
heavy metals
other environmentally toxic pollutants
Biofilms
Growth of microorganisms in a community that are attached = biofilm
Why are biofilms on medical devices an issue?
on implanted medical devices can cause infections that are extremely difficult to treat.
How do microbes contribute to the nutrition of animals such as humans and cows?
Allow for the plants to be broken down into a form that is able to be used by the body
Describe several ways in which microorganisms are important in the food and agricultural industries.
Carbon + nitrogen/ fermentation/ biofuel/ medicine- producing insulin/ preservation + production of food
What is wastewater treatment and why is it important?
The treatment of contaminated water is important so we are able to recycle and reuse the water and prevent the accumulation of toxic microorganisms that cause disease
When and by who was the microscope invented?
microscopist Antoni van Leeuwenhoek
He discovered bacteria in 1676 while studying pepper–water infusions and reported his observations in a series of letters to the prestigious Royal Society of London, which published them in English translation in 1684.
Light microscope
the sample is illuminated with visible light
Magnification
describes the capacity of a microscope to enlarge an image
Resolution
is the ability to distinguish two adjacent objects as distinct and separate.
The limit of resolution for a light microscope is about 0.2 μm
Types of lenses
objective
ocular
Total magnification
The total magnification of a compound light microscope is the product of the magnification of its objective and ocular lenses
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
lenses with higher magnification typically have higher numerical apertures
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.
What is the limit of resolution for a bright-field microscope? What defines this limit?
2.2
The limitations of bright-field microscopy include low contrast for weakly absorbing samples and low resolution due to the blurry appearance of out-of-focus material. Colloidal gold nanoparticles can serve as labels in bright-field microscopy due to their large absorption and scattering cross sections.
