Title: BACTERIA
1Ch. 18Prokaryotes
2All organisms in domains Archaea and Bacteria are
considered prokaryotic.
- What does it mean to be prokaryotic?
- Do NOT have a nucleus.
- Do NOT have membrane bound organelles (like
mitochondria, ER, Golgi) - But they DO have ribosomes, DNA, cell membrane,
cytoplasm/cytoskeleton
318.4 Bacteria and Archaea
- Prokaryotes are widespread on Earth
- Prokaryotes are the most widespread and abundant
organisms on Earth. - for perspective
- humans (eukaryotes) are one species with 7
billion individuals - a gram of soil may contain 10,000 types of
bacteria (prokaryotes) and 5 billion bacterial
cells
4Prokaryotes are widespread on Earth.
- prokaryotes are
- microscopic
- one of the earliest life forms
- found inside your body, inside volcanoes, on your
pencil- EVERYWHERE (ubiquitous)! - prokaryotes can be grouped based on their need
for oxygen - aerobic- need oxygen
- anaerobic- do not need oxygen
5The domain Bacteria and Archaea are structurally
similar but have different molecular
characteristics.
- There are two domains that contain prokaryotes
Bacteria and Archaea - domain Bacteria is more diverse and widespread
than domain Archaea - domain Archaea is more likely to be found in
extreme environments than domain Bacteria
6- Domain Archaea
- Kingdom Archaea (Archaebacteria)
- Domain Bacteria
- Kingdom Bacteria (Eubacteria)
- ancient
- most heterotrophs (some autotrophs)
- cells walls WITHOUT peptidoglycan unique lipids
- found in harsh/extreme environments
- Examples
- methanogens- dont need oxygen (anaerobic), make
methane gas - thermophiles- very hot water
- halophiles- very salty conditions, 10x saltier
than ocean water
- most diverse
- most are heterotrophs (some autotrophs)
- cell walls WITH peptidoglycan
- found everywhere
- Examples
- Escherichia coli
- Clostridium botulinum
- Bacillus anthracis
7Archaea in San Francisco Bay area extremely
high salinity. What kind of archaeans are
these?
halophiles
8Structural Comparisons of Bacteria and Archaea
- both are small, single-celled organisms
- both have
- cell walls
- plasma/cell membranes
- DNA (chromosome) is in a circle in the cytoplasm
(not found in a nucleus because they dont have a
nucleus) - ribosomes
9Structural Comparisons of Bacteria and Archaea
- both may have plasmids
- plasmid small piece of genetic material (DNA)
that can replicate separately from the
prokaryotes main chromosome
10Structural Comparisons of Bacteria and Archaea
- both are generally motile able to move on their
own - flagellum whiplike structure outside of a cell
used for movement - attached to plasma membrane and cell wall
11Structural Comparisons of Bacteria and Archaea
- both often contain pili
- pili thin, short, numerous projections that
help prokaryotes stick (attach) to surfaces and
each other pili also function in sexual
reproduction in bacteria
12- BACTERIA DO NOT HAVE CILIA!!!!
13Structural Comparisons of Bacteria and Archaea
- both have multiple shapes
- Archaea come in many shapes
- Bacteria have 3 basic shapes
- bacilli(us) rod-shaped
- spirilla(um) or spirochete spiral-shaped
- cocci(us) spherical (round)
14Bacterial Shapes
bacillus
coccus
spirillum
15Structural Comparisons of Bacteria and Archaea
coccus
bacillus
spirillum
16Structural Comparisons of Bacteria and Archaea
- Bacteria have 2 basic arrangements
- strepto strips or chains
- staphylo- clusters
17Structural Comparisons of Bacteria and Archaea
- ?If your doctor said you had Strep throat
(Streptococcus), what would shape and
arrangement of the bacteria look like under the
microscope?
- ?If your doctor said you had a staph infection
(Staphylococcus), what would shape and
arrangement of the bacteria look like under the
microscope?
- Answer
- clusters of circles
- Draw
- Answer
- chains of circles
-
- Draw
18Bacteria Structure and Function
Fill in the missing structural terms in your
notes in the Structure and Function Chart.
19Bacteria Structure and Function
Fill in the terms from the chart on the diagram
below. Then, number these structures (1,2,3)
starting with the outside of the cell and moving
to the inside cell wall, capsule, plasma
membrane
20Bacteria have various strategies for survival.
- Reproductive strategies
- binary fission
- conjugation
- and
- Strategies for surviving harsh conditions
21Gene Exchange in Prokaryotes
- binary fission prokaryotic asexual reproduction
- Bacteria divides in half producing identical
offspring. - chromosome copies itself (like in DNA
replication) - the cell grows to double its size
- plasma membrane grows inward and divides the cell
into two, each with a full set of the original
cells genes.
22- binary fission prokaryotic asexual reproduction
23Gene Exchange in Prokaryotes
- conjugation exchange of genetic material
through a hollow bridge of pili connecting 2 or
more cells
24Surviving Harsh Conditions
- endospore specialized cell with a thick,
protective wall formed for survival during
unfavorable conditions - bacterium copies its chromosome
- produces a wall around the copy
- thick wall withstands drying out (desiccation),
temperature change, and disinfectants - can last for centuries
Examples Bacillus anthracis (causes anthrax)
Clostridium botulinum (causes botulisma form of
food poisoning)
2518.5 Beneficial Roles of Prokaryotes
- Prokaryotes provide nutrients to humans and other
animals. - prokaryotes are key in animal digestive systems
in balanced communities - mutualistic symbionts
- host benefits
- make vitamins and other compounds
- keep away harmful microbes by filling niches they
might occupy (out-competing them) - bacteria benefits
- break down food while getting a place to live
- place to live has stable pH and temperature
26Develop mutualistic relationships with other
organisms Ex. the fish provides the
bioluminescent bacteria under its eye with
organic materials, the fish uses its living
flashlight to lure prey and to signal mates.
potential mates.
27- Prokaryotes provide nutrients to humans and other
animals. - many foods humans eat are fermented by bacteria
- ferment chemically break down
- yogurt
- pickles
- cheese
- sauerkraut
- soy sauce
- vinegar
28- Prokaryotes play important roles in ecosystems.
- PRINCIPLE DECOMPOSERS (along with fungi)
- recyclers of carbon, nitrogen, hydrogen, and
sulfur through ecosystems - photosynthesizers cyanobacteria produce oxygen
were key to increasing the oxygen content of
early earth
29Cyanobacteria
30- Prokaryotes play important roles in ecosystems.
- - nitrogen fixers - fix nitrogen convert
atmospheric nitrogen into ammonia and other
nitrogen compounds plants can use - some nitrogen-fixing bacteria are free-living
- some are symbionts
- legumes plants (peas, beans, alfalfa, and
clover) with mutualistic relationship with
nitrogen-fixing bacteria living in nodules in the
roots - bacteria provide usable nitrogen to the plant in
the form of ammonia - plant provides food and shelter to the bacteria
31- Prokaryotes play important roles in ecosystems.
- bioremediaters break down pollutants
- some bacteria can digest oil, others can digest
poison - important role in recycling and composting
- biodegradable able to be broken down by
bacteria - many plastics are NOT biodegradable.
32Summary of Beneficial Bacteria (not in notes)
- bacteria are decomposers and nitrogen fixers
- bacteria are used to make certain foods like
cheese and yogurt. - bacteria are used in the manufacture plastics
and many pharmaceuticals. - bacteria digest cellulose in animals
- bacteria are used in sewage treatment plants
- bacteria are used to make medications and
biological molecules like insulin (a protein
bacteria transcribe and translate the human
gene!)
3318.6 Bacterial Diseases and Antibiotics
- Some bacteria cause disease.
- some bacteria cause disease in plants and animals
by disrupting the host organisms homeostasis in
2 basic ways - invading tissues and attacking cells
- making poisons, or toxins, that can be carried by
blood through the body
34- Some bacteria cause disease.
- tuberculosis (TB) bacteria invade host tissues
and use them for nutrients - Mycobacterium tuberculosis multiply in the lungs,
killing white blood cells that respond to the
invasion - hosts reaction is to release enzymes that cause
swelling results in lung damage - a healthy immune system can usually defeat a
potential TB infection
35- Some bacteria cause disease.
- food poisoning
- Staphylococcus aureus normally live in nasal
passages - when transferred to food it results in serious
illness - toxin it produces is not destroyed by cooking
- Clostridium botulinum causes botulism which can
be deadly due to the toxin produced by the
bacteria - usually caused by improper canning of foods
contaminated with spores - bulging or dented cans may signal the presence of
the bacteria
36- Some bacteria cause disease.
- opportunistic infections normally harmless
bacteria can be destructive when introduced to a
part of the host that is not adapted to them - example Streptococcus normally present in our
mouth and noses and the surface of our skin, but
can become pathogenic in a sore or cut - also causes strep throat
37- Antibiotics are used to fight bacterial disease.
- antibiotic chemical that kills or slows the
growth of bacteria, often by stopping bacteria
from making cell walls - produced naturally by some species of bacteria
and fungi - used as medicine for humans and other animals
because we/they lack cell walls - antibiotics dont work on viruses they dont
have cell walls either - antibiotics dont work on Archaea either - they
have a different type of cell wall (no
peptidoglycan) - overuse of antibiotics can lead to illness if the
intestinal flora or microbes are wiped out and
can lead to resistance
38- Not all antibiotics attack the cell walls of the
bacterium (penicillin does) - Some disrupt other processes structures unique
to bacterial cells - Ex) tetracyclin disrupts protein synthesis in
bacteria because of some minor (but important!)
differences in the process/structures involved
39- Antibiotics are used to fight bacterial disease.
- Gram stain the Gram stain is a method of using
stain to tell two groups of bacteria within
Kingdom Bacteria apart. This was an important
technique developed which is helpful in not only
diagnosing bacterial infectious but also in
determining the antibiotic medicine that the
doctor chooses to treat the infection. - Gram negative bacteria stain red. These bacteria
only have a thin layer of peptidoglycan in the
cell wall, but have an extra layer of lipids. - Gram positive bacteria stain purple. These
bacteria have a thicker layer of peptidoglycan in
the cell wall. Typically Gram bacteria are
easier to kill with antibiotics.
40- Antibiotics are used to fight bacterial disease.
41- Bacteria can evolve resistance.
- multi-drug resistant bacteria serious public
health issue resulting from inappropriate and
incomplete use of antibiotics - called superbugs
- resistance is a result of natural selection
bacteria that are unaffected by an antibiotic due
to a random mutation survive to produce other
bacteria that are also naturally resistant to the
same antibiotic (binary fission) - genes for resistance are acquired when plasmids
are exchanged during conjugation
42- Bacteria can evolve resistance.
- factors contributing to this issue include
- overuse prescribing an antibiotic for a viral
infection is just one example - underuse failing to take the entire course of
antibiotics prescribed - the weakest bacteria are destroyed first, leaving
behind those that are more resistant - additional (the entire prescription) may kill all
of the bacteria or reduce their numbers to a load
your immune system can handle - misuse feeding them to livestock to increase
their growth rate leads to resistant bacteria
present in the food as well as in the animals
43Antibiotic Resistant Bacteria Video Clip
Antibiotic Resistance Video Clip
44Other diseases caused by Bacteria(not in notes)
- anthrax
- lyme disease
- E. coli (food poisoning)
- bubonic plague
- typhoid fever cholera
- strep throat dental caries (cavities)
- diphtheria pneumonia
- Salmonella (food poisoning)
45Yellow bacillus bacteria in the lining of the
human nose. This species causes pneumonia if the
person doesnt have a strong immune system
(opportunistic infection).
46Questions to Ponder
- Why are bacteria important organisms in the
ecosystem?
- What are the shapes and arrangements of bacteria
and how can these be used in classification?
- In what ways are bacterial beneficial to us?
Explain.
- Describe bacterial diseases including cause,
symptoms, and transmission.