An overview * * What is Bacteria s job? What about bad

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Prokaryotes

• An overview

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What to Expect

• These notes focus on
• Cell theory
• Prokaryotes

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Cell theory

• All living things are made of cells
• Cell can only come from other cells
• All functions of a living thing are carried out
  in cells
• Reminder the functions of living things are
  respiration, metabolism, growth, adaptations to
  the environment, reproduction, homeostasis and
  interdependence

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On your worksheet

• State the 3 points of cell theory.
• List the 7 characteristics of life

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• There are two main groups of cells, prokaryotic
  and eukaryotic cells.
• Similarities all are alive, all have a cell
  membrane, all have DNA
• Differences appearance, structure, reproduction,
  and metabolism.
• biggest differences are between cells of
  different kingdoms
• . 

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On your worksheet

• List the 2 types of cells

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Where do we find Prokaryotes?
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Prokaryotes are bacteria

• Prokaryotes are simple organisms

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Diagrams courtesy - http//www.cod.edu/people/facu
lty/fancher/ProkEuk.htm
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According to current scientific thought
Prokaryotes were formed 2 billion years before
eukaryotes (or about 3.5 billion years ago)
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On your worksheet

• According to current scientific thought, about
  how old are prokaryotes?

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Prokaryotesfrom the Greek meaning before nuclei
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Why before nuclei?

• Prokaryotic cells have no nucleus.
• Prokaryotes DNA is circular (it has no ends).
• Small circlets of DNA are called Plamids.
• Prokaryotic DNA is naked it has no histones
  associated with it and does NOT form chromosomes

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On your worksheet

• What does prokaryote mean?
• Why is the term prokaryote used to describe the
  cells we are talking about?

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All Prokaryotes are in the monera kingdomdomains
Bacteria and Archaea

• bacteria

• Cyanobacteria
• also known as blue-green algae

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On your worksheet

• What kingdom to do all prokaryotes belong to?

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Prokaryote Characteristics

• Very small size.
• Lack membrane-bound organelles inside the cell
• have few internal structures that are
  distinguishable under a microscope.
• genetic information is in a circular loop called
  a plasmid
• Strong cell walls resistant to environmental
  changes

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Size

• Bacterial cells are very small, roughly the size
  of an animal mitochondrion
• about 1-2µm in diameter and 10 µm long
• µm one millionth of a meter, or equivalently
  one thousandth of a millimeter.

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Video
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On your worksheet

• What is the size of an average Prokaryote?

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2. Lack membrane-bound organelles inside the
cell
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3. have few internal structures that are
distinguishable under a microscope.
http//www.umanitoba.ca/science/biological_science
s/lab3/biolab3_2.htmlExamine
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4. genetic information is in a circular loop
called a plasmid

• E. coli cell dividing.
• E. Coli Grows in human intestine
• Has a single, circular chromosome
• contains DNA as plasmids
• Plasmids are extra-chromosomal DNA

http//www.bio.mtu.edu/campbell/prokaryo.htm
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5. Strong cell walls resistant to environmental
changes
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On your worksheet

• Describe the 5 items used to classify a prokaryote

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Shapes

• Spiral
• Rod shaped
• Spherical

This spiral shaped bacteria is the causitive
agent of syphilis Treponema pallidum

• Cocci - sphereBacilli - rodsSpirilla spirals
• Staph - in clustersStrep - in chains

Streptococcus sp. Chains of nearly-spherical
bacteria.From The Rockefeller University.
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cocci
Means Sphere-shaped
Streptococcus sp. Chains of nearly-spherical
bacteria.From The Rockefeller University.
Streptococcus pyogenes
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Spirilla
Means Spiral-shaped
This spiral shaped bacteria is the causitive
agent of syphilis Treponema pallidum
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Bacilli
Means Rod-shaped

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Intermediate Shapes

• short rods - (coccobacilli).
• commas - (vibrii).

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Rare shapes

• squares stars irregular

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groups or clusters

• Cocci can divide to form
• chains (streptococci)
• groups of 4 (tetrads)
• irregular clusters (staphylococci).

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groups or clusters

• Real-life examples

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• Bacilli can divide to form chains
  (streptobacilli)
• spiral bacteria normally remain as separate
  individuals.

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To review
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Or, how bacteria move
bacterial motility
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overview of info

• Some bacteria can be identified by how they move
• Stationary (dont move at all)
• Flagella (whip like structure)
• Rotation and tumbling
• Number of flagella
• Monotrichous
• Lophotrichous
• Amphitrichous
• Peritrichous
• Spiraling
• Slime and ooze

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remain stationary

• Which means, some bacteria simply do not move - -
  at all, ever.

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flagella

• Some bacteria are propelled (moved) by a
  whip-like structure called a FLAGELLA
• Flagella can be rotated like tiny outboard motors
• When flagella rotation is reversed, bacteria
  tumble about in one place.

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Arrangements of flagella

• Monotrichous- Having one flagellum at only one
  pole or end
• Lophotrichous- having a tuft of flagella at one
  end
• Amphitrichous- having flagella at both ends
• Peritrichous- Having flagella uniformly
  distributed over the body surface

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spiral

• Like a corkscrew
• Kinking different parts of the bacteria body by
  hardening one side and then the other

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Slime and ooze

• Other bacteria secrete a slime layer and ooze
  over surfaces like slugs.
• slime layer is formed by decomposition of the
  cell wall.

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bacterial Reproduction

• Or, how one bacteria can become many

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Click picture to watch video on Bacterial
Reproduction
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Replication

• Binary fission
• one cell splits into two cells,
• offspring are genetically identical to parent

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• Bacterial conjugation
• a form of sexual reproduction where bacteria
  exchange genetic information before dividing
• offspring have new genes (and new traits)

Figure 1. Schematic drawing of bacterial
conjugation. 1- Donor cell produces pilus 2-
Pilus attaches to recipient cell, brings the two
cells together 3- The mobile plasmid is nicked
and a single strand of DNA is then transferred to
the recipent cell 4- Both cells recircularize
their plasmids, synthesize second strands, and
reproduce pili. Both cells are now viable donors.
http//parts.mit.edu/igem07/index.php/Boston_Unive
rsity/Conjugation
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• Transformation
• bacteria incorporate genes from dead bacteria
• Transduction
• viruses insert new genes into bacterial cells.
• This method is used in biotechnology to create
  bacteria that produce valuable products such as
  insulin

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Movement

• Some can't move, while others have long
  threadlike flagella.
• If bacteria doesnt move, how does it get from
  person to person?

E.Coli flagella
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How does a Bacteria get energy?
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Metabolic Diversity
Or, how bacteria get energy
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overview of info

• 4 main ways bacteria get energy
• Chemoheterotrophs
• Photoheterotrophs
• Photoautotroph
• Chemoautotroph
• Energy is released through either cellular
  respiration or fermentation
• Oxygen demands vary
• Obligate aerobe
• Obligate anaerobe
• Facultative anaerobe

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Heterotrophs

• Heterotrophs get energy by eating other organisms
• Chemoheterotrophs
• Eat other organisms for Energy
• Eat other organisms for carbon supply
• Photoheterotrophs
• Use sunlight for energy
• Eat other organisms for carbon supply

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Heterotrophs

• At least 95 of life on earth is heterotrophic
  (including people)
• staphylococcus aureus
• Chemoheterotroph
• eat same foods as humans
• Release toxins that cause food poisoning
• Antibiotic resistant strains cause breakout
  pictured here

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Heterotrophs

• Jannaschia
• marine bacteria found in coastal and open ocean
  surface waters.
• aerobic anoxygenic phototroph (AAnP),
• Gets its energy from light, not from eating other
  organisms
• responsible for oceanic photosynthesis in the
  ocean and the ocean carbon cycle.

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Autotrophs

• Autotrophs make their own energy from inorganic
  (not-living) molecules
• Photoautotroph
• Uses sunlight (light energy) to convert CO2 and
  H2O into Carbon compound and oxygen
• Chemoautotroph
• Make organic carbon molecules from CO2 using
  energy from chemical reactions involving ammonia,
  hydrogen sulfide, nitrites or iron

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Autotrophs

• Cyanobacteria
• Also called bluegreen algae
• Found in fresh water, salt water and on land near
  sources of light
• Photoautotroph
• Use sunlight to make energy and carbon compounds

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Autotrophs

• Chemoautotrophs get energy and carbon from
  chemical reactions
• Some live near ocean vents like the one pictured

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cellular respiration

• Once bacteria have eaten they need to break
  down their food to make energy
• The process of breaking down organic compounds
  into ATP (energy cells can use) is called
  cellular respiration
• Same 1st step to begin with, but the lack or
  presence of oxygen determines the 2nd step
• Step one Glycolisis
• Step two Fermentation or Kreb Cycle

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cellular respiration

• To oversimplify the first step
• called glycolysis
• Doesnt require Oxygen (anaerobic)
• Takes place in the cytosol (fluid surrounding
  organelles) of a cell
• Breaks glucose into pyruvate creating ATP and H
  in the process

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cellular respiration

• If NO oxygen is present after glycolysis,
  Fermentation begins
• 3 types
• Lactic acid Fermentation
• Occurs in muscles
• causes muscle cramps due to acidity
• Occurs in Bacteria
• used to make cheese and yogurt
• Acetic Acid Fermentation
• Occurs in Bacteria
• Forms vinegar
• Alcohol Fermentation
• Forms ethyl alcohol and CO2
• Used to make bread, wine and beer

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cellular respiration

• If Oxygen IS present after glycolysis, Acetyl CoA
  is made and the Kreb cycle begins
• well save the chemical details of this process
  for another class, but, basically it produces a
  whole lot of ATP for the cell to use

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cellular respiration

• SOME BACTERIA REQUIRE OXYGEN, SOME DONT
• OBLIGATE AEROBES
• OBLIGATE ANAEROBES
• FACULTATIVE ANAEROBES

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Obligate aerobe

• Obligate aerobes NEED oxygen to live
• OBLIGATE means required to
• AEROBE means oxygen
• Release energy through cellular respiration or
  fermentation
• Example myobacterium tuberculosis

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Obligate anaerobe

• Obligate anaerobes DO NOT need oxygen to live
• OBLIGATE means required to
• ANAEROBE means without oxygen
• Release energy through cellular respiration or
  fermentation
• Example clostridium botulinum

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facultative anaerobe

• Facultative anaerobes can survive with or without
  oxygen
• Facultative means able to function in different
  ways
• These bacteria can live just about anywhere
• Example E. coli

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FunctionsWhat does Bacteria do?

• decomposers, agents of fermentation, and they
  play an important role in our own digestive
  system.
• involved in many nutrient cycles such as the
  nitrogen cycle, which restores nitrate into the
  soil for plants.

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What is Bacterias job?
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What about bad Bacteria?
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• Describe a benefit of having bacteria on Earth
• Describe a bad bacteria and how it affects
  people.

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Images of Bacteria

• http//www.ulb.ac.be/sciences/biodic/ImBacterie2.h
  tml
• http//www.buckman.com/eng/micro101/bacteria.htm