Option F
Microbes and Biotechnology
Abi S.
Eleah W.
• There are three domains of living organisms:
Archaea, Eubacteria, and Eukaryota. Archaea
are the most basic and live in extreme
conditions; for example, they have no histone
proteins, cell wall, or introns. Eubacteria are
more advanced, with a cell wall and many
different shapes (cones, comma-shaped,
spirals, etc.), and Eukaryota are the most
advanced, with histone proteins and introns.
• Types of bacteria:
– Methanogens- obligate anaerobes
– Thermophiles- live in warm areas with
temperature close to boiling
– Halophiles- live in saline habitats
– Gram positive- simple cell wall one layer thick
– Gram negative- several cell walls with
peptidoglycan between
– Viruses- have naked or enveloped capsids
• Six specific bacteria classes
– Saccharomyces- heterotrophs, use extracellular
digestion, no method of locomotion
– Amoeba- heterotrophs, use pseudopodia to move
– Plasmodium- heterotrophs that use intracellular
digestion, slide on substrate
– Paramecium- heterotrophs, intracellular digestion,
swim using cilia
– Euglena- autotrophs and heterotrophs, swim using
flagella
– Chlorella- autotrophs, no locomotion
• Nitrification/Denitrification- bacteria in soil and
on root nodules fix nitrogen, convert ammonia
into nitrites and nitrites into nitrate, and remove
nitrogen from the soil to release into the
atmosphere
• Methane creation- Eubacteria turn inorganic
material into organic material, which becomes
acetate, carbon dioxide, and hydrogen.
Methanogenic bacteria create water and
methane and break down acetate to create
methane and carbon dioxide.
Sewage Treatment
– Raw sewage in rivers and lakes increases saprotrophs
numbers to break it down, which causes biochemical
oxygen demand and increased organism death. Algal
blooms and eutrophication results.
– Trickling filter beds- bed of stones with saprotrophs
that break down waste
– Reed bed system- waste put into reed beds, which
contain saprotrophs to break down waste (which also
fertilizes the reeds)
• Forms of gene therapy
– Reverse transcriptase- makes DNA from RNA
– Somatic- replaces body cells in an individual
– Germ line- treating gametes and genes
– Viral vectors- replace defective genes in a host
organism
– Can be dangerous
• Alcohol and bread production
– Beer- Saccharomyces ferments barley and malt to
produce beer containing ethanol and carbon dioxide
– Wine- yeast ferments grapes until ethanol kills the
bacteria
– Bread- bacteria ferments sugars to produce the
carbon dioxide that causes bread to rise until the heat
of baking kills them (before alcohol is produced)
• Soy sauce- Aspergillus oryzae is mixed with soy
beans and wheat, salt and water are added after
an incubation period, and then it is left for
months while fermentation occurs
• Preservation- acid kills bacteria before they
can break down material and sugar/salt draw
water out of microbes through osmosis to kill
them
• Food poisoning- one example is salmonella,
which is obtained from raw eggs, meat, and
fecal matter; it lives in the intestine of the host
and causes digestive problems
• Photoautotroph:
• An organism that uses light energy to generate
ATP and produce organic compounds from
inorganic substances.
• Ex: Cyanobacteria (e.g. Anabaena)
• Photoheterotroph:
• An organism that uses light energy to generate
ATP and obtains organic compounds from other
organism.
• Ex: Rhodospirillum; Rhodobacter
• Chemoautotroph:
• An organism that uses energy from chemical
reactions to generate ATP and produce organic
compounds from inorganic substances.
• Ex: Nitrobacter
• Chemoheterotroph:
• An organism that uses energy from chemical
reactions to generate ATP and obtain organic
compounds from other organisms.
• Ex: Mycobacterium tuberculosis; Lactobacillus
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Photoautotrophs vs. Photoheterotrophs
Both create ATP from light
Photoautotrophs use CO2 as carbon source
Photoheterotrophs use organic molecules as
carbon source
• Chemoautotrphs vs. Chemoheterotrophs
• Chemoautotrophs get energy from chemicals
and carbon from inorganic compounds
• Chemoheterotrophs get energy and carbon
from organic compounds
Cyanobacteria diagram
• Bioremediation
• Use of microbes, fungi, plants or enzymes to
remove environmental contaminants from
water and soil by breaking down the
chemicals or converting them so that they can
be filtered out
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Oil Spills:
Microbes oxidate hydrocarbons
Pesticide Pollution:
Microbes gradually break down pesticides
Selenium pollution:
Microbes absorb selenium ions and oxidate them
into the less toxic metallic selenium
• Solvent pollution:
• Microbes dechlorinate solvents in anaerobic
conditions
Methods of pathogen transmission
• Ingestion of food can transmit food poisoning
• Polluted or unclean water can cause disease
• Air/ water droplets in the area can carry
organisms
• Animal vectors
• Puncture wounds/ cuts break the skin barrier and
allow entry of bacteria or viruses.
• Sexual contact with an infected person
• Intracellular bacterium such as Chlamydia rely on host's metabolism
for certain of metabolic processes. Chlamydia specifically lives
within the epithelial cells of that line the genital tract. It does not
produce toxins nor directly damage cells, but can cause long-term
problems which remain unremedied by the immune system
because they are not detectable inside the cells
• Extracellular bacterium such as Streptococcus live inside the host,
but in the intercellular spaces and use the nutrients available there
while producing toxins and damaging cells. Streptococcus produces
toxins that kill host cells and molecules called invasins which split
open and dissolve host cells. Unlike Chlamydia, it is targeted by the
immune system as an infection.
Endotoxins: lipopolysaccharides in the walls of
Gram-negative bacteria that cause fever and
aches.
• Exotoxins: specific proteins secreted by
bacteria that cause symptoms such as muscle
spasms (tetanus) and diarrhea.
Irradiation
• Some microbes are resistant to ionizing radiation
• Free radicals may alter the flavour
• Some consumers are afraid to use products of 'radiation'
Pasteurization
• Application of alternating extreme high and low temperatures is very effective at
killing pathogens if done for long enough in the correct conditions.
• Usually not done because it alters the flavor of the product being pasturized
Antiseptics
• Kill/prevent microbial growth and prevent infection without damaging skin and
mucous membranes, though they are too toxic to be consumed internally
Disinfectants
• Extremely effective sterilisation that cannot be used on living tissue.
• Useful for sterilisation of medical tools, floors, furniture, etc
• Does not kill endospores
• Antibiotics are antimicrobial agents produced by
microbes which inhibit or kill other microbes via
cell wall synthesis inhibition, which inhibits the
production of peptidoglycan for the cell walls of
bacteria, protein synthesis inhibition, which
occurs when the antibiotics block some stage of
protein synthesis by attacking the bacterial
ribosomes, or nucleic acid inhibition, which
affects the synthesis of DNA/RNA or attach to
DNA/RNA so that they cannot be read and
thus interferes with the growth of bacterial cells
Life Cycle of the Influenza Virus
• Virus attaches to cell surface by means of specific receptors
• Virus is taken up via endocytosis
• Uncoating occurs in endosome and viral RNA is released
into the cytoplasm
• RNA of viral genome transported into the nucleus, where it
is copied and replicated by the viral enzyme into RNA,
acting as template for more RNA and a messenger
• Viral envelope proteins begin to assemble in cell membrane
• Lysis, or the bursting of the cell, occurs and releases new
virus particles to attack other cells.
• Epidemiology is the study of the occurrence,
distribution and control of disease.
A pandemic is a very widespread epidemic that
affects a large geographic area, such as a
continent
• Ex: Spanish Flu of 1918
• Killed 40-50 million people
• Origin believed to be in China
• Travel of soldiers for WWI aided spread of flu
• Hang washing encouraged, public gathering
banned
Malaria
Cause
• Plasmodium (falciparum, vivax, ovale, malariae)
Transmission
• Transmitted from one person to the next by a
female Anopheles mosquito which feeds on human blood
• Plasmodia reproduce in the gut of the female mosquito
• Egg sac ruptures and releases sporozoites which travel to the
salivary glands, enter bloodstream with mosquito bite and travel to
the liver, at which point they change form, and then invade red
blood cells
Symptoms/Effects
• Anemia, bouts of fever chills, shivering, joint pain, and headache.
• Prion Hypothesis
• States that the causal agent for spongiform
encephalopathies consists only of misfolded proteins
(PrPSC).
• Abnormally shaped prions that can cause normal
proteins (PrPC) to change to an abnormal shape,
resulting in cell death.
• Chronic, degenerative diseases of the nervous system
that form holes in brain tissue, causing memory loss,
personality changes, speech lapses and ultimately
death.
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