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Bacteria
4D identify and describe the role of bacteria in maintaining
health such as in digestion and causing diseases such as in
streptococcus infections and diphtheria.
Bacteria Fun Facts!
• 99% of all bacteria are helpful!!
Bacteria Fun Facts!
• One healthy bacterium could reproduce into a colony of more
than 2 million in just 7 hours!!
Bacteria Fun Facts!
• There are more bacteria on your body than there are humans on
the entire planet!!
Three Domains to categorize all living organisms
Six Kingdoms
• Eubacteria
• Archaebacteria
• Protista
• Fungi
• Plantae
• Animalia
Two Kingdoms of Bacteria:
Archaebacteria
Eubacteria
Common Characteristics:
All Prokaryotes
Lack nucleus
Single cell
Cell walls
ARCHAEBACTERIA
• Live in extremely harsh environments, like
thick mud, extremely salty environments,
hot springs
• Lack cell wall made of peptidoglycan
• DNA sequences similar to eukaryotes
• May be ancestors of eukaryotes (us)
Places ARCHAEBACTERIA live
Deep Sea Vents
Hot Springs
EUBACTERIA
• Live almost everywhere,
fresh water, salt water, land,
within the human body
• Larger of the 2 kingdoms
• Surrounded by cell walls
containing peptidoglycan
Bacteria—What Are
They?
Bacteria—What Are They?
Overview
 Are Prokaryotic cells
 No organized
nucleus
 Few cell parts
 Contain a single
circular chromosome
Structure of Bacteria
• Flagella – whip-like
structure used for
movement
• Pili – short hair-like
projections used for
movement
• Ribosomes – protein
synthesis
• Peptidoglycan – lipid
layer inside cell wall.
Cell
wall
Peptidoglycan
Flagellum
Cell
membrane
DNA
Ribosome
Pili
Bacterial Morphology
Endospores
• Endospores are the most resistant living structures
known.
• formed by some bacteria to resist drying out, boiling,
heat, freezing, radiation, and chemicals.
• Can survive several hours boiling & may remain viable
for years
• Remains dormant until conditions are favorable again
then resumes growth and reproduction.
• Exposure to proper stimuli (food, warmth & moisture)
the spore germinates and a new vegetative cell emerges.
• Endospores can survive for thousands of years!
What Do They Look
Like?
Appearance
It is single celled.
With three basic shapes:
• Bacillus – Rod Shaped
• Coccus – Round/Sphere
• Spirilus – Spiral
Shape
Cocci:
Diplococcus
Streptococcus
Staphylococcus
Neisseria gonorrhoeae
Streptococcus pyogenes
Streptococcus pneumoniae
Shape
Bacilla:
(Rod Shaped)
Diplobacillus
Streptobacillus
Shape
Spirilla:
Spiral or corkscrew shaped
Role of Bacteria in
Symbiotic Relationships
Importance of Bacteria
Not all bacteria are bad!!
• Bacteria are vital to maintaining the living world
because:
– Some are producers – put oxygen into the
atmosphere
– Some are decomposers – break down dead organic
matter
– Some have human uses; E. coli. lives in the human
intestines and produces vitamins the body cannot
produceUsed to make yogurt and other dairy products
– Nitrogen fixation – bacteria live in symbiotic
relationship with legumes (bean plants) to convert
nitrogen gas to a usable form of nitrogen for plants.
Beneficial Bacteria
• Protein source
• Wine
•
•
•
•
Oil Eating bacteria
Bacterial Cement
Sewage Plants
Agriculture
– Nitrogen fixing bacti
Beneficial roles of Bacteria
• Chemosynthetic Autotroph
Use
chemicals
to make
energy
(inorganic
compounds)
Beneficial roles of Bacteria
• Bacteria can also be helpful in the
large intestine by preventing
infections and producing substances
we need, such as vitamin B and K.
Beneficial roles of Bacteria
Bacteria in the stomachs of cows and sheep are
what enable them to digest grass.
Bacteria are also essential to the production of
yogurt, cheese, and pickles.
Beneficial roles of Bacteria
Bacteria are necessary to decompose
dead plants and animals to recycle.
• Saprophytes
– Decomposing dead organisms
Genetic Engineering
Bacteria have been
genetically altered to
produce insulin
Bacteria have been
genetically altered to
break down oil and other
pollutants
METABOLISM
• Difference between autotroph
and heterotroph?
• Difference between aerobic
and anaerobic?
Some Cause Diseases
Tetanus
Whooping Cough
Typhoid Fever
Paratyphoid Fever
Cholera
Plague
Tuberculosis
Meningitis
Clostridium tetani
Bordetella pertussis
Salmonella typhi
Salmonella paratyphi
Vibrio cholorae
Yersinia pestis
Mycobacterium tuberculosis
Neisseria meningitidis
https://www.youtube.com/wat
ch?v=znnp-Ivj2ek
Common Bacterial Diseases
• Strep-throat
• Tooth Decay
• Chlamydia
• Lyme Disease
• Tuberculosis
• Cellulitis
• Methicillin-resistant
Staphylococcus aureus
(MRSA) is a bacterium that
causes infections in
different parts of the body.
• Most often, it causes mild
infections on the skin,
causing sores or boils
How to control bacteria…
• Sterilization – heat, boiling water, hand washing
• Disinfectants – Example – lysol
• Food storage and processing – canning,
keeping food cold or frozen
• Vaccines – many bacteria have vaccines to
prevent them
Preventing Invasions
• First line of defense against disease microbes is
your body surface
(Skin & linings of tubes that lead to exterior)
• In addition, epithelial tissues secrete materials
that kill microbes on the body surface
– Salts in sweat and tears draw H2Oout of microbes,
shrinking & killing the ones that live on your skin and
in your eyes
– Acids in stomach & vagina burn microbes
Preventing Invasions
– Enzyme (lysozyme) in sweat, tears, saliva,
earwax & nasal secretions ruptures bacteria
by digesting cell walls
– Mucus & cilia trap microbes & push them to
the exterior
If microbes have penetrated the
body…..
Three lines of defense
– Macrophages within vessels, searching and
devouring microbes
– Inflammatory response within the lymph nodes
– Fever – elevated body temp. helps fight microbes
by enhancing the effect of interferons,
accelerating the reproduction of T cells &
removing minerals from the body so that bacteria
cannot use them as nutrients
Along with antibodies, you have
Complement Proteins
• It is a bundle of proteins that travels within
the blood stream at all times.
• Some enzymes from complement kill the
microbe by digesting a hole in its outer
membrane.
• Others guide macrophages and assist in
other ways.
Treatments for Bacteria
• Once a harmful bacteria has infected the body,
antibiotics can be used to attack and destroy the
bacteria
400 degree-waterspewing vents
located along the
Mid-Ocean Ridge
Who lives here:
Photoautotrophs or
Chemoautotrophs?
How do they
Reproduce?
Bacterial
Reproduction
• Asexual
– Binary Fission
• Sexual
– Conjugation
– Transformation
– Transduction
Bacterial Reproduction
Asexual Reproduction
Sometime prokaryotes divide by Binary Fission (Asexual
Reproduction).
• Binary Fission results in 2 identical
bacteria through normal cell division.
– The DNA molecule replicates itself and the DNA molecules
become attached, side by side, to the inner surface of the plasma
membrane.
– The membrane elongates separating the 2 molecules.
Binary Fission
Cell
reproduction
by “splitting” in
to two new
cells.
Reproduction
Binary Fission:
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf:
:500::500::/sites/dl/free/0073375225/594358/BinaryFission.swf::Bin
aryFission
https://www.youtube.com/watch?v=7sZ5Nz8_cfc
Bacterial Reproduction
Sexual Reproduction
(DNA Variability)
Many times, bacteria can exchange genetic
material before dividing by Binary Fission.
Because two different bacteria unite to
exchange genetic information, it is said to
be Sexual Reproduction.
• Sexual Reprod. Types (DNA Variability)
– Conjugation
– Transformation
– Transduction
Bacterial Reproduction
DNA Variability
Conjugation
(Direct cell to cell contact)
Sex Pilus
– F Factor codes for the sex pilus
• Cells lacking F Factor can only receive DNA during
conjugation and is called F• Cells possessing F+ Factor have a sex pilus & can donate
DNA
– F+ cell contacts the F- cell using its sex pilus & a
conjugation bridge is formed
– A copy of its DNA is transferred from the F+ to
the F- cell.
(F- eventually being changed into F+)
Conjugation
Exchanging
genetic
material
between
bacterial cell
through a pilus
Bacterial Morphology
Pilus (Pili)
• Short slender tubes formed of protein
subunits that extend from the cell wall
– Other pili – help bacteria adhere to objects like
O2 and food
– Sex pilus – involved in conjugation
Conjugation Cont.
– The conjugation bridge (F+ to F-)can be used to transfer either a
plasmid or a portion of the bacterial chromosome.
• A plasmid is an extra chromosomal circular
DNA segment that can reproduce
independently of the bacterial
chromosome.
Conjugation:
http://www.learner.org/channel/courses/biology/archive/animatio
ns/hires/a_infect1_h.html
Bacterial Reproduction
DNA Variability
• Transformation
– When a bacterium dies, fragments of its DNA may be released
intact
– If this fragment contacts a competent member, it can be bound to
the cell and taken inside (not all bacteria can do this)
– After it’s been taken up, part of it is incorporated into the
genome (DNA) of the recipient
Bacterial Reproduction
DNA Variability
• Transduction (Virus-mediated transfer)
– Transfer of genetic material from one bacterium to another by a
virus
Bacteria Respiration
• Depending on where they are found,
bacteria use different types of respiration:
• Obligate Aerobes – require a constant
supply of oxygen in order to survive.
• Obligate Anaerobes – must live in the
absence of oxygen.
• Facultative Anaerobes – can live with or
without oxygen.
Questions
1. Which organism lives in the human
intestine and aids in the digestive process?
A.
B.
C.
D.
The bacterium Escherichia coli
The fungus Trichophyton rubrum
The protozoan Entamoeba coli
The algae Fucus vesiculosus
2. Some antibiotics cause patients to exhibit
digestive side effects. These side effects are
most often the result of —
A. bacteria being killed in the digestive tract
B. the antibiotics being converted into stomach
acids
C. too much water being drawn into the digestive
tract
D. the stomach wall being torn
3. Many species of bacteria can be found in the
human mouth. Which of these explains the great
variety of bacteria in the mouth?
A. Large volumes of air cause bacteria to change
form.
B. Salivary glands cause mutations in bacterial
populations.
C. The presence of nutrients makes the mouth a
favorable habitat.
D. Calcium in the teeth provides a suitable pH
environment.
4. Bacteria are present in the digestive tract
of some herbivores. The bacteria break
down plant cellulose, making it possible for
the herbivore to digest plant material. These
bacteria live in a stable environment with
sufficient food and water. The herbivore and
the bacteria in this relationship —
A.
B.
C.
D.
benefit each other
compete for survival
are producers
are secondary consumers
5. How does using killed or weakened
bacteria in an immunization help the body
prevent infections?
A.
B.
C.
D.
Antibodies are formed that fight those types of bacteria.
The body develops a fever that kills beneficial bacteria.
Bacterial reproductive cycles are disrupted.
Bacteria-fighting viruses are activated.
6. Which of the following is found in both
cells and viruses?
A.
B.
C.
D.
Silica
Genetic material
Digestive cavity
Flagella
7. Which of the following is found in both
cells and viruses?
A.
B.
C.
D.
Silica
Genetic material
Digestive cavity
Flagella
8.
People infected with the human
immunodeficiency virus (HIV) have an
increased risk of dying from secondary
infections. Which of these best explains how
HIV increases the danger of secondary
infections?
A.
B.
C.
D.
HIV produces antigens that damage red blood cells.
HIV adds genetic material from harmful microbes.
HIV destroys helper T cells.
HIV consumes beneficial microbes in the body.
9.
People infected with the human
immunodeficiency virus (HIV) have an
increased risk of dying from secondary
infections. Which of these best explains how
HIV increases the danger of secondary
infections?
A.
B.
C.
D.
HIV produces antigens that damage red blood cells.
HIV adds genetic material from harmful microbes.
HIV destroys helper T cells.
HIV consumes beneficial microbes in the body.
Viruses vs Bacteria
Virus
Bacteria
Not a cell; smaller than a cell
Dormant outside a cell
Single Cell; oldest form of life;
no nucleus
Requires a host cell to reproduce
for them
Reproduce through cell division
Cannot take in food
Large size
Cannot expel waste
Found in many environments;
soil, water, air, bodies of other
organisms, with or without
oxygen
Consists of two parts: outer
coat of protein and hereditary
material-DNA or RNA
Cytoplasm contains hereditary
material; DNA in circular
structure called plasmic
Diseases: HIV, AIDS, Flu,
Smallpox, Warts
Diseases: Strepthroat, Anthrax,
Diphtheria, MRSA
Virus Versus Bacteria