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Bacteria

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Bacteria=Prokaryotes Prokaryotes Eukaryotes No organelles except Lots of organelles ribosomes INCLUDING NO NUCLEUS! NUCLEUS! Bacterial Characteristics Oldest ... – PowerPoint PPT presentation

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Title: Bacteria


1
Bacteria
2
BacteriaProkaryotes
  • Prokaryotes Eukaryotes
  • No organelles except Lots of organelles
  • ribosomes INCLUDING
  • NO NUCLEUS! NUCLEUS!

3
Bacterial Characteristics
  • Oldest organisms 3.5 billion yrs. old.
  • Live in almost every environment.

4
Eubacteria
  • Kingdom Eubacteria
  • Common environments
  • Believed to be the ancestors of mitochondria and
    chloroplasts---organelles in eukaryotic cells

5
Archaebacteria
  • Kingdom Archaebacteria
  • Found in extreme environments
  • Ancient bacteria-gave rise to eukaryotic cells

6
Characteristics-Size
  • Size
  • Red blood cell is 250Xs larger than a bacterium
  • 1 gram of soil can contain 2.5 BILLION bacteria
  • Relative bacteria size

7
Characteristics-Shapes
  • Shapes
  • Cocci-round
  • Bacilli-rod-shaped
  • Spirilla-spiral

8
Bacterial structure
  • Interior structures
  • Has DNA and cytoplasmno nucleus or other
    membrane bound organelles EXCEPT ribosomes for
    protein synthesis!

9
Bacterial Structure
10
Bacterial structure
  • Exterior structures
  • Flagella--whip-like tail for locomotion
  • Cell membrane to control what goes in and out
  • Cell wall for protection

11
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12
2 Types of Cell Walls
  • 2 types of cell walls found in bacteria
  • Identified as Gram or Gram -
  • Theres a chemical difference b/t them.

13
Gram staining
  • Special staining process
  • Gram positive is purple Gram negative is not.

14
2 Types of Cell Walls
  • Gram
  • Thick cell wall
  • Holds purple stain,
  • so cells look purple
  • Gram
  • Two thin layers
  • make up cell wall
  • Doesnt hold purple
  • stain so appears pink

15
2 Types of Cell Walls
  • Treatment of illness due to these bacteria is
    different!
  • Gram - generally NOT affected by antibiotics
  • i.e. E. coli
  • Gram affected by antibiotics
  • i.e. S. pneumoniae

16
Bacterial Reproduction
  • Binary fission
  • Bacterias process of reproduction where 1
    becomes 2.
  • Results in clones
  • 1000s of bacteria
  • that result from one
  • undergoing binary
  • fission is called a
  • colony

17
How are bacteria so diverse?
  • They have several ways of exchanging genetic
    information.
  • Conjugation--exchanging DNA through a straw-like
    tube.
  • Transformationanother method of transferring
    genes between bacteria.

18
Useful Bacteria
  • Decomposers- Recycle nutrients such as CO2 ,
    water, nitrogen, and phosphorus

19
Useful Bacteria
YUMMY!
  • Nitrogen fixation- soil bacteria take nitrogen
    gas from the air (N2) and change it into a
    useable form that plants can absorb (NH3-
    ammonia.)
  • Plants use the nitrogen to produce their proteins
    and DNA.
  • Some bacteria are photosynthetic and also provide
    oxygen

N2
Bacteria
NH3
20
Useful Bacteria
  • Food-- yogurt, olives, pickles, chocolate
  • Drugs -- insulin production
  • Clean up oil spills
  • Animal digestion and vitamins, including our own
  • Microbe Discovery Movie

21
Harmful Bacteria
  • Pathogen- Disease causing organisms.
  • Pathologists -scientists who study pathogens.
  • Not many bacteria are pathogenic ONLY 1!
  • Disease Transmission
  • a.) Water
  • b.) Air
  • c.) Food
  • d.) Animals/Insects
  • e.) Human Contact

22
Bacterial Diseases
  • Tuberculosis
  • Syphilis
  • Bubonic Plague
  • Typhus
  • Tetanus
  • Lyme Disease

23
Controlling Bacterial Growth
  • What do bacteria require to live and reproduce?
  • - Food, water, and the right climate.
  • -Give bacteria these things, and they grow
  • remove them and they dont.

24
Nutrition and Energy
  • How do bacteria eat?
  • 1.) Autotrophic- self-feeders
  • MAKE food
  • Photosynthetic so they release oxygen!!!
  • HAVE NO ORGANELLES SO NO CHLOROPLASTS!!!
  • Chemosynthetic
  • 2.) Heterotrophic- other-feeders
  • GET food
  • Consumers
  • Decomposers
  • Parasites

25
Growing Bacteria on Petri Dishes
  • Plastic Petri dishes have a Jell-O like substance
    called AGAR with nutrients and water for bacteria
    to grow on.

26
Growth Curve
  • When bacteria are grown on agar in a Petri dish,
    their food and water supply (AGAR) is limited
  • They live through four phases of growth without
    addition of more agar.
  • Lag
  • Log
  • Stationary
  • Death

27
GROWTH CURVE
28
Controlling Growth
  • Antibiotics
  • Antibiotic resistance
  • Sanitizing--Antiseptics and Disinfectants
  • Freezing
  • Cooking
  • Pasteurizing
  • Dehydrating
  • Vaccination

29
Antibiotics
  • Alexander Fleming
  • Mold on his Petri dish had a zone of inhibition
    around it where bacteria didnt grow.
  • Mold released the
  • antibiotic penicillin
  • Antibioticagainst life any
  • substance produced by a
  • microbe that slows the
  • growth of other microbes.

BACTERIA
MOLD
30
Antibiotics
  • 2 ways antibiotics control bacteria
  • Bacteriocidal- kill them by blocking protein
    synthesis
  • Bacteriostatic- prevent them from undergoing
    binary fission (prevents them from making new
    cell walls.)

BACTERIA
Each paper disk has antibiotics on it. Which
antibiotic is more powerful?
31
Antibiotics
  • Antibiotics are made by
  • fungus (mold)
  • other bacteria, the most common Streptomyces.
  • present day antibiotics are synthetic
    modifications of naturally occurring ones.
  • Work on Gram bacteria

32
Antibiotic Resistance Movie
  • Antibiotic resistant bacteria are not affected by
    certain antibiotics!
  • Can be resistant due to
  • Special cell walls (i.e. Gram bacteria) OR
  • Special antibiotic resistant genes
  • Dont finish antibiotics
  • Weaker bacteria destroyed.
  • Resistant bacteria still live and pass on
    resistant genes through binary fission,
    conjugation and transformation

33
Conjugation
34
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35
Sanitizing
  • Antiseptics---Chemicals used to inhibit growth of
    bacteria on living tissues

36
Sanitizing
  • DisinfectantsChemicals used to inhibit growth of
    bacteria on NON-living things.

37
Freezing
  • How would this control the growth of bacteria?
  • Would freezing kill all the bacteria?

38
Cooking
  • Cooking can control bacterial growth and kill
    most bacteria if heated to certain temps165F or
    hotter.
  • Use a meat thermometer
  • Wash hands after handling raw meat

39
Pasteurizing
  • Using heat to kill bacteria in liquids.

40
Dehydrating
  • How would this control the growth of bacteria?

41
Vaccination
  • Prevents you from getting the disease. DOES NOT
    CURE YOU.
  • Fast and strong immune system memory cells
    produced which provides immunity just like if you
    got the disease (i.e. chicken pox.)

42
Vaccination
  • Can use weakened (attenuated) bacteria or viruses
  • MOSTLY use parts of bacteria or virusesacellular
  • Vaccine video

43
Structure of a Virus
Virus a microscopic particle that invades and
takes over cells Relative virus size 100 of
viruses are pathogenic!!!!
44
Structure of a Virus (cont.)
  • Made of
  • nucleic acid (DNA or RNA)
  • surrounded by a protein coating (capsid).

45
Viral Replication
  • Parasites (dependent on host for replication)
  • Steps of viral replication
  • 1.) Recognition of marker protein on specific
    cell types.
  • 2.) Attachment
  • 3.) Injection (of nucleic acid)
  • 4.) Assembly
  • 5.) Lysis (cell bursting)

46
Recognize and Attach
47
Injection
48
Replication
49
Lysis
50
Characteristics of Living Things
  • Homeostasis stable internal conditions
  • Metabolism use energy
  • Reproduction
  • Made of cells
  • Genetic material
  • VIRUSES ARE NOT LIVING THINGS!
  • No metabolism, homeostasis, reproduction, or
    cells

51
Replication Cycles of Viruses2 Types
  • Viruses have either a lysogenic or lytic
    replication cycle
  • Lytic virus genetic material used quickly to
    take over cell, then lysis occurs to release
    newly made viruses.
  • Influenza and Ebola

52
Lytic Viruses
53
Lysogenic Viruses
  • Lysogenic virus nucleic acid fuses with the
    host cells until lysis (bursting) LATER.
  • When infected cell undergoes cell cycle
  • replication of virus DNA with cell DNA
  • many cells infected
  • During this dormant period no illness is seen
  • HIV and herpes

54
Lysogenic Virus
55
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56
Protection Against Viruses
  • ANTIBIOTICS DONT WORK ON VIRUSES!!!
  • Vaccines
  • Used as PREVENTION, NOT A CURE!
  • Only useful against viruses that do not mutate
    and evolve (change) rapidly.
  • HIV, common cold viruses and flu virus- DNA
    mutates rapidly. No permanent vaccine!
  • Tamiflu is an antiviral medicine, but not
    reliable.

57
HIV
  • Devastating Africa
  • 30 million people have the disease
  • Infects T cells of immune system
  • Can lie dormant in our DNA for 10 years
  • Ryan White

58
HIV Dormancy
  • During dormancy, people look healthy, but can
    still spread the disease by
  • Sexual contact (including oral)
  • Sharing needles
  • Blood transfusions
  • Organ transplant
  • Baby to mother
  • Blood to blood contact of any kind
  • HIV video clip

59
Other Viral Diseases
  • HIV
  • Common cold
  • Chicken pox
  • Measles
  • Rabies
  • Rubella
  • Mumps
  • Influenza (flu)
  • Small pox
  • Hepatitis
  • Yellow fever
  • Ebola
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