Bacteria & Viruses

Chapter 19

Bacteria Microscopic life covers nearly every square

centimeter of Earth. All bacteria are prokaryotes. Classifying Prokaryotes

Prokaryotes are identified by their size, shape, the way they move, the way they obtain energy.

Prokaryotes are placed into two kingdoms▪ Eubacteria: Larger of the two kingdoms, very diverse,

live everywhere.▪ Typical eubacteria lives in the human intestines (ex. E.Coli)

▪ Archaebacteria: Similar to eukaryotes, live in harsh environments.

Identifying Prokaryotes Shape: Three different shapes

Bacilli- Rod shaped Cocci- Spherical shaped Spirilla- Spiral/corkscrew shaped

Cell Wall: Two different types of cell walls Thin walls- Peptidoglycan layers Thick walls-Lipid layers Gram Staining: Methods used to identify wall type▪ Gram Positive: Identifies thicker, walls stain turns dark

violet.▪ Gram Negative: Identifies thinner, walls stain turns pink or

light red.

Identifying Prokaryotes Cont…

Movement: If they move & how they move. Propelled by flagella (whip-like structure). Lash, snake, or spiral forward.

Metabolism: The way the organism obtains and uses energy. Heterotroph- Those that can not make their own food.▪ Chemoheterotrophs: Takes in organic material for food & carbon▪ Photoheterotrophs: Carry out photosynthesis and in take organic

material for carbon. Autotroph- Those that are capable of making their own

food.▪ Photoautotrophs: Use light to convert CO2 and H2O into carbon

compounds.▪ Chemoautotrophs: Do not need light to convert CO2 and H2O in

carbon compounds.

Energy

Obligate aerobes: Require oxygen to live

Obligate anaerobes: Can not live in the presence of oxygen, in fact in some cases oxygen can kill these organisms.

Facultative anaerobes: Can function in different ways depending on their environment.

Growth & Reproduction of Prokaryotes

Bacteria can reproduce at astonishing rates, some reproduce every 20 minutes.

Types of Reproduction: Binary Fission-Prokaryotes copies DNA, divides in

half and produces two identical cells (asexual). Conjugation-Two prokaryotic cells exchange

genetic material to reproduce (sexual). Spore Formation- When conditions are right

prokaryotes can produce spores which can later when conditions are right will germinate and become bacteria.

Importance of Bacteria Decomposer

Breaking down of dead or decaying organisms. Nitrogen Fixer

Converts nitrogen gas into a form that can be usable by plants.

Human Uses Industry Technology Synthesizing vitamins Genetic Engineering Oil Spills

Viruses Viruses are particles of nucleic acid,

protein, and in some cases lipids. Typically viruses have a D.N.A. core and

a protein coat▪ Capsid: The protein coat of the virus

Viral Infection

Lytic Infection: A virus enters a cell , makes copies of itself and then causes the cell to bust and release the copies it made of the virus.

Lysogenic Infection: A virus integrates its D.N.A. into the D.N.A. of the host cell, and the viral genetic information replicates along with the host cell’s D.N.A.

Viral Infection

Viruses

Retroviruses: A virus that infects a cell and then uses it’s R.N.A. to make copies of it’s D.N.A. and then that D.N.A. is inserted into the host cells D.N.A. Called retro because it goes from

R.N.A.D.N.A. the opposite of other viruses. Can lay dormant in the host cell for long

period of time. Some cancers are cause by retroviruses as

well as H.I.V. the virus that causes A.I.D.S.

Diseases Caused by BacteriaBacteria in Humans:

Some bacteria infect the body then damage tissues and cells by breaking them down for food

Some Bacteria release toxins that interfere with normal cell activities.

We use Vaccines & Antibiotics to prevent and or treat bacterial infections.

Bacteria in Animals: Many bacteria can affect both humans and

animals.

Diseases Caused by Bacteria

Diseases Caused by BacteriaDisease Bacterium Effect

Lyme Disease Borrelia burgdorferi Fever, Fatigue, AchesTetanus Clostridium tetani Muscle Spasms, DeathTuberculosis Mycobacterium

tuberculosisFatigue, Fever, Night Sweats,

Diphtheria Corynebacterium dihtheria

Fever, Sore Throat

Bacterial Meningitis

Neisseria meningitidis High Fever, Nausea, Fatigue

Strep Throat Streptococcus pyogenes

Sore Throat, Fever, Swollen Glands

Tooth Decay Streptococcus mutans Decay of Tooth Enamel

Controlling Bacteria

There are many ways to control bacterial growth Sterilization- Killing bacteria using heat Disinfectants- Killing bacteria using

chemicals Food Processing

Diseases Caused by Viruses Viral Disease in Humans:

Viruses disrupt the human body’s equilibrium Many viruses infect and kill cells Can’t be treated with antibiotics but can be

vaccinated for. (some viruses eliminated by vaccines)

Viral Disease in Plants & Animals: Viruses infect plants & animals very similarly to

the way they infect humans, but in many cases carry be more severe and even can cause cancer.

Diseases Caused by Viruses

Diseases Caused by VirusesDisease Effect Transmission

Common Cold

Sneezing, Sore Throat, Headache Inhalation

Influenza Fever, Sore Throat, Nasal Congestion

Contact or Inhalation

Smallpox Fever, Fatigue, Back Ache, Rash Contact or Inhalation

Warts Skin Growths Contact with wartAIDS Immune System Destroyed Contact w/bodily

fluidChickenpox Fever, Itchy Rash, weakness Contact w/rashMeasles Fever, Rash, White Spots, Cough, InhalationHepatitis A Jaundice, Nausea, Fatigue,

Stomach PainHuman Waste

Hepatitis B Diarrhea, Nausea, Fatigue, Joint Pain

Contact w/bodily fluid

Hepatitis C Jaundice, Nausea, Fatigue, Stomach Pain

Contact w/bodily fluid

West Nile Fever, Fatigue, Body ache Mosquito bitePolio Fever, Muscle weakness,

headacheInhalation