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
(No Transcript)
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
(No Transcript)
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
(No Transcript)
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