Bacteria

I.All bacteria are Prokaryotes- single celled organisms that lack a nucleus.

Peptidoglycan

A. Cell Wall B. Cell

membrane

C. Ribosome

D. CiliaE. DNAF. Flagellum

II. Classifying Prokaryotes- all prokaryotes were once in Kingdom Monera; now divided into 2 kingdoms

A. Kingdom Eubacteria1. Largest group2. Can live almost anywhere, even in your intestines (ex. E.-coli)3. Have cell walls4. Unicellular

B. Kingdom Archaeabacteria1. Live in extreme environments (ex. Methanogens

and Halophiles) 2. Have cell walls3. Unicellular

E-coli in human intestines provides vitamin K and some of the B vitamins

Tube Worm Symbionts/Sulfide Oxidizing Bacteria

Tube Worms

Underwater communities thrive without sunlight

Dead Sea

Archaebacteria- Extreme Environments

Halophiles- “Salt Lovers”

Archaebacteria- Extreme Environments

Methanogens- Live in lots of Methane

Archaebacteria- Extreme Environments

Thermophiles- Extrme “Temperature Lovers”

III. Identifying Prokaryotes- use shape, cell wall chemical structure, movement method of obtaining energy and releasing energy, and growth and reproduction.

A. Shape- 3 types

1. Bacilli-rod shaped 2. Cocci- sphere shaped 3. Spirilla- corkscrew shaped

Identify the following:

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B. Cell wall structure- 2 types, identified by Gram staining (used for prescribing antibiotics)

1. Cell wall containing mainly peptidoglycan appear purple =

Gram Positive.

2. Cell wall with extra outer layer of lipids appear red = Gram Negative

Which of these bacteria are gram positive?

C. Movement- some have flagella (long whip-like tail), some glide on slime, some don’t move

D. Obtaining Energy

1. Producers-(Autotrophs) make their own food a. Examples: Cyanobacteria – carry out photosynthesis

2.Consumers- (Heterotrophs) most prokaryotes consume food.

E. Releasing energy- 3 ways to release energy from food.

1. Aerobes- use cellular respiration, need oxygen

2. Anaerobes- use fermentation, poisoned by oxygen

3. Facultative anaerobes- use fermentation or cellular respiration (can live anywhere)

F. Growth and Reproduction

1. Binary fission- asexual reproduction, produces two identical daughters cells, most bacteria do this

2. To survive harsh conditions like drought or freezing temperatures many bacteria produce thick protective covering around DNA called an Endospore

III. E.Q. What role do bacteria play in nature?

A. Producers- capture sun’s energy through photosynthesis, food source for consumers and produce oxygen

B. Decomposers- bacteria help recycle nutrients by breaking down dead organisms; they break down complex compounds into simpler ones.

C. Nitrogen Fixers- bacteria are the only known organisms that can convert nitrogen into a form that plants are able to use.

1. Some plants (legumes) even have a symbiotic relationship in which bacteria live on their roots and help them absorb nitrogen.

Disease causers- (pathogens)

1. Bacterial Pathogens cause disease 2 ways.

a. Heterotrophic Bacteria can break down body tissue-Tuberculosis

b. Bacteria can release toxins (poisons). Streptococcus- toxins cause rash called scarlet fever.

IV. Prevention and Treatment

A. Prevent bacterial diseases with vaccines, made from another form of the bacteria, stimulates immune system.

B. Bacterial infections are treated with antibiotics, substances that stop bacterial reproduction.

C. Controlling bacteria- sterilization destroys bacteria by using great heat or chemicals.

Ribosome

Section 19-1

The Structure of a Eubacterium

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Cell wall

Cell Membrane

PilliDNAFlagellum

Peptidoglycan

I. What is a virus? A. Virus comes from the Latin word for

poison.B. Viruses can only be seen with Electron

MicroscopeC. Non-cellular particle made up of genetic

material (DNA or RNA) and a protein coat. Not considered to be living things!

D. Parasites! CANNOT carry out life processes unless within a host (living cell). Usually host specific- infect only one type of host.

T4 BacteriophageTobacco Mosaic

Virus Influenza Virus

Capsid

Tail

DNA

Tail fiber

RNACapsid

Surfaceproteins Envelope

RNA

Capsid

Section 19-3

Figure 19-13 Virus Structures

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II. Viral Diseases

A. Mostly caused by virus destroying cells in body.

B. Cause human diseases such as polio, measles, AIDS, and the common cold

C. CANNOT be treated with antibioticsD. Best Protection is prevention - Prevented by

safe practices or Vaccine if available. (Vaccines must be used before infection begins)

Rabies

SARS- flu-like virus that leads to severe pneumonia

Ebola virus- liquification of internal organs and severe bleed out

E. Oncogenic Viruses cause cancer b/c their DNA disrupts the normal

growth of cells

F. Retorviruses- RNA – genetic information copied backward- from RNA to DNA example: AIDS

III. Kinds of Viruses

A. Viruses are classified by their shape, the kind of hereditary material they contain, organism that they infect and reproduction.

B. The protein that covers a virus gives it its shape.

C. Viruses are often named for the disease that they cause (Polio) or the organ or tissue that they infect (SARS).

IV. Viruses are generally destructive.

A. Why? Virus has to be inside a living cell to reproduce. The cell that it reproduces in is a host cell. A virus destroys its host cell. How?

1. Lytic Cycle -how a virus reproduces

a. When a virus enters a cell and is active it causes the cell to make new viruses. This will eventually destroy the host cell.

V. Steps of Lytic Cycle1. Attach-virus attaches to the surface of a cell

2. Inject- the hereditary material of the virus injects itself into the cell.

3. Copy-the viral DNA takes control of the cell and the cell begins to make new virus particles.

4. Assembles- viral particle are assembled into new viruses

5. Release-the cell bursts open and hundreds of new virus particles are released. These new virus particles go on to infect other cells.

Bacteriophage

Bacteriophage DNA

Bacteriophage protein

Bacteriophage protein coat

Bacteriophage DNA

Bacterialchromosome

Lytic Cycle

Section 19-3

Figure 19-14 The Lytic Cycle

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Attach

Inject

Copy

Release

Assemble

VI. Lysogenic Cycle- When viral DNA becomes part of the cell’s DNA without immediately destroying the cell or making new viruses.

A. This is a latent virus; can exist inside host cells for many years. Can become active at any time. Ex- Cold sores.

VII. Steps of Lysogenic cycle

1. Virus attaches to the cell and injects hereditary material into the cell.

2. Virus becomes part of the cell’s DNA.3. Cell divides, creating viral DNA along

with its own DNA.4. This can happen for years until virus

becomes active5. Then it will enter the lytic cycle

Bacteriophage DNA

Bacterialchromosome

Prophage

Lytic Cycle

Lysogenic Cycle

Section 19-3

Figure 19-15 A Lysogenic Infection

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a) Virus attaches and invades

b) Virus’ DNA becomesPart of Cell’s DNA

c) Cell divides

c) Viral DNA separates from Cell’s DNA and becomes active

d) New viruses are made

e) Cell breaks open and Releases virus

Bovine Spongiform Encephalopathy

Mad Cow Disease

VIII. Prions- no genetic material (DNA nor RNA) only protein which infects the nervous tissue of the brain (scientists think they cause Mad Cow Disease).