Bacteria UNIT 3 - Chapter 19. Prokaryotes Definition: single-celled organisms that lacks a NUCLEUS...
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Transcript of Bacteria UNIT 3 - Chapter 19. Prokaryotes Definition: single-celled organisms that lacks a NUCLEUS...
BacteriaUNIT 3 - Chapter 19
Prokaryotes• Definition: single-celled organisms that
lacks a NUCLEUS
• OLD Classification – MONERA• Prokaryotes called BACTERIA• All BACTERIA were in the Kingdom –
MONERA
• CURRENT Classification• Prokaryotes (BACTERIA) are divided into 2
very different KINGDOMS• EUBACTERIA• ARCHAEBACTERIA
Eubacteria vs. Archaebacteria• BOTH: Prokaryotes, unicellular, autotrophic
or heterotrophic• EUBACTERIA:
• Larger kingdom• Cell Wall contains PEPTIDOGLYCAN• EX: E. coli and Streptococcus
• ARCHAEBACTERIA:• Some similar DNA sequences to Eukaryotes
(thought to be ancestors)• No PEPTIDOGLYCAN in cell wall• Live in EXTREME conditions (3 types):
• Methanogens—poisoned by O2
• Thermaphiles—live in extreme temps.• Halophiles—live in high saline
are classified into the kingdoms of
live in harsh environments such as
include a variety of lifestyles such as
Bacteria
Eubacteria Archaebacteria
Infecting large organisms
Thick mudLiving in soilAnimal
digestive tracts
Salty lakes Hot springs
E. coli Methanogens
Shapes of Bacteria
Obtain and Use ENERGY• AUTOTROPHS (make their food)
• Photoautotrophs: use photosynthesis to make chemical energy out of sunlight
• Found near lots of light
• Chemoautrophs: get energy from inorganic chemical reactions
• HETEROTROPHS (take in ORGANIC materials)• MOST PROKARYOTES • If food is not handled correctly, bacteria
may eat it and in the process leave poisonous chemicals behind
Bacteria in Nature• DECOMPOSERS “Natures
Recyclers”• Help the ecosystem “Recycle” and break
down dead matter into simpler substances• Works as sewage treatment; produces
purified water; releases nitrogen and CO2
• EXAMPLE: Nitrogen Fixation• Process by which nitrogen is converted
into a form plants can use• Nitrogen gas (N2) must be change into
ammonia (NH3)
Nitrogen-FIxers• Rhizobium (bacteria)
• Attached to the roots of soybeans and legumes
• Convert nitrogen gas to ammonia• Ammonia helps plant (soybean)
Bacteria and DiseasePATHOGENS (disease causing)• Cause disease by 2 methods• Damage TISSUES of organism
• Mycobacerium tuberculosis• Cause Tuberculosis by breaking down lung tissue
• Release TOXIN (poisons)• Salmonella and E. coli• Common types of food poison release toxins• Streptococcus • Causes strep throat releases toxin into the blood
stream
Prevention and Treatment•Vaccines: dead or weakened pathogens (bacteria or viruses) used to induce formation of antibodies or immunity against the pathogen (must be given before)•Antibiotic: block growth and reproduction of bacteria (cure bacterial diseases)
Tooth decay
Lyme disease
Tetanus
Tuberculosis
Salmonella food poisoning
Pneumonia
Cholera
Streptococcus mutans
Borrelia burgdorferi
Clostridium tetani
Mycobacterium tuberculosis
Salmonella enteritidis
Streptococcus pneumoniae
Vibrio cholerae
Regular dental hygiene
Protection from tick bites
Current tetanus vaccination
Vaccination
Proper food-handling practices
Maintaining good health
Clean water supplies
Disease Pathogen Prevention
Human Uses of Bacteria• FOOD PRODUCTION: cheese, yogurt,
pickles, • INDUSTRIAL: digest oil, remove waste
and poisons, synthesize drugs, genetic engineering
• CONTROLLING BACTERIA• STERILIZTION: means of destroying
• Heat (boiling water)• Chemicals (disinfectants)
• INHIBITING or SLOWING growth• Refrigeration (low temps just slow)• Salt, Vinegar and sugar
VIRUSESUNIT 3 chapter 19
Viruses• STRUCTURE:
• Particles of Nucleic Acid (DNA, RNA), proteins, and lipids
• CORE – contains DNA or RNA• CAPSID – outer protein coat
• CHARACTERISTICS:• Many different sizes and shapes• Only REPRODUCE when infecting living
cell (virus is not a cell)• Viruses are very specific
Review of Living and NON-living8 Characteristics
1. Made of Cells
2. Reproduce
3. Based on Genetic Code
4. Grow and Develop
5. Obtain and use energy
6. Respond to environment
7. Homeostasis
8. Evolve
Viruses are considered NON-living. Why?
Viruses are NON-LivingNON-life like (contrasting)
• Not made of cells
• Do not reproduce independently
• Do not Grow/Develop/Respond to environment
• Do not Obtain and use energy
Life-like (comparing)
• Evolve
• Contain DNA or RNA
Viral Infections are Specific• Highly specific to type of cells they
infect.• Plant viruses do not infect animal cells• Animal viruses only infect certain species
of animals
• BACTERIOPHAGES:• Virus that infects bacteria• EX: T4 and Lambda
Types of Viral Infections: LYTICVirus Enters cell and causes it to
BURST Quickly!!!1. Virus attaches to cell wall2. Virus injects DNA into cell3. Virus takes over cell metabolism and
produces its own proteins & nucleic acids
4. Proteins and Nucleic acids combine to form NEW viruses
5. Enzyme breaks down cell wall & NEW viruses leave to infect other cells
Bacteriophage (virus) attaching Bacteria
Bacteriophage enzyme lyses thebacterium’s cell wall, releasingnew bacteriophage particles thatcan attack other cells.
Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage takes over
bacterium’s metabolism, causing synthesis of new bacteriophage proteins and nucleic acids
Bacteriophage injects DNA into bacterium
Bacteriophage attaches to bacterium’s cell wall
Bacteriophage
Bacteriophage DNA
Bacteriophage protein
Bacteriophage protein coat
Bacteriophage DNA
Bacterialchromosome
Lytic Cycle
Types of Viral Infections: LYSOGENIC
• TWO Cycles• LYSOGENIC• LYTIC
• DIFFERS from Lytic because…• DNA is embeded into host DNA• Virus does NOT KILL cell right away
Steps of LYSOGENIC Infection1. Virus injects DNA
2. DNA forms a circle (Prophage)
3. DNA circle (prophage) combines with the bacteria DNA
4. Virus DNA (prophage) replicates with bacterial DNA
5. Virus DNA (prophage) exits bacterial DNA (forms own circle)
6. Begin Lytic cycle… New viruses Burst cell and leave
Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles
Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells
Bacteriophage DNA inserts itself into bacterial chromosome
Bacteriophage DNA (prophage) may replicate with bacterium for many generations
Bacteriophage DNA (prophage) can exit the bacterial chromosome
Bacteriophage DNA forms a circle
Bacteriophage DNA
Bacterialchromosome
START: Bacteriophage injects DNA into bacterium
Prophage
Lytic Cycle
Lysogenic Cycle
Section 19-3
Lysogenic Infection
Go to Section:
LYSOGENIC Cyle to LYTIC Cycle• Lysogenic cycle (latent or dormant) • The virus will switch to LYTIC cycle under
ADVERSE conditions (Stress, radiation, chemical change)
Diseases:• Polio, Measles, Mumps, AIDS, Flu, Rabies, Yellow Fever,
ColdsLytic Infections• (colds-adenoviruses)Lysogenic Infections (Herpes, EBV, HPV)• (Epstein-Barr EBV) Lytic-Mononucleosis / Lysogenic-
predisposed to lymphoma• (HPV) lytic-genital warts / lysogenic cervical cancerRetroviruses (RSV, HIV, HTLV, FLU)• Genetic material is RNA and makes copy into DNA• Retro- means “backwards”; develops mutations quickly• RSV (Rous sarcoma virus) can lead to sarcoma; HTLV can
lead to leukemia… virus can transform/mutate host DNA
Human Viruses
Oncogenic viruses
Retroviruses
Adenoviruses
Herpesviruses
Poxviruses
DNA
RNA
DNA
DNA
DNA
cancer
cancer, AIDS
respiratory infections
Chickenpox, Mono
smallpox
Type of Virus Nucleic Acid Diseases
WARNING• Following slides contain graphic
pictures.
• Herpes sores…
Herpes Simplex 1
Herpes Simplex II
Symptoms and Prevention• PREVENTION:
• Best way to protect against a viral infection is PREVENTION
• Vaccines (for some)• Only good before virus• Stimulates immune response
• SYMPTOMS:• Caused when virus attacks and destroys
body cells• Lytic cycle (see symptoms)• Lysogenic cycle (virus is dormant, no
symptoms….but still contagious)
AIDS (Acquired Immune Deficiency)CAUSED BY:
• HIV (Human Immunodeficiency Virus)• Virus destroys helper T cellsEFFECTS:• Depresses cell-mediated immunity, Deficit in
antibodies• Immune system turned upside down• Increasing frequency of infections, often rare
types, Lesions on skin, DementiaTRANSMITTED:• In body secretions (blood, semen, vaginal
secretions)• Sexual Intercourse, use of IV needles, some
documented cases by oral sex