viruses, bacteria, and fungus how they affect us!
TRANSCRIPT
Viruses, Bacteria, and FungusHow they affect us!
What are Viruses
• A virus is a tiny, non-cellular, non-living particle that enters and then reproduces inside a living cell.
• All viruses have two basic parts: A protein coat that protects the virusAn inner core made of genetic
material (contains the instructions for making new viruses)
Vary in shapes and sizesThese round viruses are responsible for causing West Nile disease in animals.
This robotlike virus, called a bacteriophage, infects bacteria.
Once inside the cell, the virus’s genetic material takes over many of the cell’s functions. It instructs the cell to produce the virus’s proteins and genetic
material. These proteins and genetic material then assemble into new viruses.
• Active Viruses• 1. A virus attaches to the surface of a
bacterium.• 2. The virus injects its genetic material
into the bacterium.• 3. The virus’s genetic material takes
over the cell functions of the bacterium. The cell starts to produce the virus’s proteins and genetic material.
• 4. The proteins and genetic material assemble into new viruses that fill the bacterium.
• 5. The bacterium bursts open, releasing new viruses. The viruses go on the infect more cells.
• Hidden Viruses• 1. A virus attaches to the surface of a
bacterium.• 2. The virus injects its genetic material
into the bacterium.• 3. The virus’s genetic material becomes
part of the genetic material of the bacterium.
• 4. After some time, the virus’s genetic material removes itself and becomes active.
• 5. The cell begins to produce the virus’s proteins and genetic material, which assemble into new viruses.
• 6. The new viruses crowd the bacterium. Finally, the cell burst open and releases the new viruses.
The Bad and The Good• Viruses and Diseases
• Mild viral diseases last for short times with quick recovery (colds)
• Serious viral diseases have more serious effects on the body (AIDS)
• Viruses do not affect only humans but also plants and animals
• Apple trees – Apple Mosaic Virus• House pets (dogs and cats) –
rabies and distemper
• Usefulness of Viruses
• In gene therapy, genetic material is added to a virus to use the virus as a “messenger service” to deliver to affected cells
• For example: for the treatment of cystic fibrosis
Bacteria
DNA
Anton Van Leeuwenhoek
• Discovered bacteria by accident while looking at scrapings from his teeth
Prokaryotic Cells• Also called bacteria• World’s smallest cells• No nucleus• Circular DNA (shaped like a rubber band)• No membrane-covered organelles• Contains cytoplasm and ribosomes• Some may have a flagellum for movement
Prokaryotes• Cells that do not
have a nucleus• Exist almost every
where on earth• Grow in numbers so
great you can see them with the unaided eye
Bacterium Shapes• Cocci~ Sphere
shaped bacteria• Bacillus~ Rod
shaped bacteria• Spirrillium ~ Spiral
shaped bacteria• Flagella~ Leg-like
structures that help to propel the bacterium.
Movement - Bacteria
• Flagella ~ Tail like structure the whips around to propel the bacterium
How bacteria eat?Autotrophs Make their own energy
Using Solar energyEg. Cyanobacteria
Make own EnergyUsing Chemical energyEg. Archaebacteria
Chemotrophs
Heterotrophs Obtain food by eatingEg. E-coli
Respiration• Bacteria need a constant supply of energy to
carry out their functions. • This energy comes from the food they eat.• The process of breaking down food to release
energy is called RESPIRATION.• A few bacteria do not need oxygen to break
down their food.- anaerobic• Some bacteria die if oxygen is present in their
surroundings.
Bacterial Reproduction• Binary Fission• Cellular organism
copies it’s genetic information then splits into two identical daughter cells
• Asexual reproduction
• Conjugation• Two bacteria swap
genetic information through a thread-like bridge
• Sexual reproduction
Sometimes, conditions in the environment become “UNFAVORABLE” for the growth of bacteria. Ex. No food source, too dry, too wet, too hot, too cold
Bacteria will form endospores to survive these conditions. An endospore is a small, rounded, thick-walled, resting cell that forms inside the bacterial cell.
Symbiosis•Close relationship between two species in which at least one species benefits from the other•Live together for LIFE
Parasitism•Bacteria exploit the host cell, injuring them
Mutualism•Symbiosis in which two of the species live together in such a way that both benefit from the relationship•Eg. E-coli
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The role of Bacteria in Nature
Oxygen Production -
Food Production
Environmental Recycling
Environmental Cleanup
Health and Medicine
• Oxygen Production – Autotrophic bacterial use the sun’s energy to produce food with oxygen as a product.
• Food Production – Bacteria is used to make vinegar, buttermilk, yogurt, sour cream, and cheeses. (Food is heated enough to kill most harmful bacteria through a process called pasteurization.)
• Environmental Recycling – Decomposers are organisms that break down chemicals on dead organisms into small chemicals.
• Environmental Cleanup – Some bacteria help clean up Earth’s land and water. Some bacteria prefer to eat oil. They convert the poisonous chemicals in oil into a harmless substance.
• Health and Medicine – You have natural bacteria in your stomach to help with digestion. Some help your body make needed vitamins. Others compete for space preventing harmful bacteria from taking up residency. Bacteria is used to make human insulin for diabetic patients.
Nitrogen Fixations• Process by which nitrogen in the atmosphere
is converted into a form that can be used by living things by bacteria.
Viruses, Bacteria, and Your Health
• Infectious diseases – illnesses passed from one organism to another
Can spread through:Contact with an infected personA contaminated objectInfected animalAn environmental source
How infectious diseases are spread
Infected person –Direct - touching, hugging,
kissing Indirect -inhaling drops from a sneeze or cough
Contaminated Objects – Sharing eating and drinking objects
touching contaminated surfaces
Infected Animals –
Animal bites
Environmental Sources –
Food, soil, water
Antibiotic
• A chemical that can kill bacteria without harming a person’s cells
Antibiotic resistance
• When some bacteria are able to survive in the presence of an antibiotic
Toxin
• A poison that can harm an organism
Vaccine
• A substance introduced into the body to stimulate the production of chemicals that destroy specific viruses or bacteria
Antibiotics and Bacterial Diseases
Lyme DiseaseSymptoms: rash at bite, chills, fever, body aches,
joint swellingSpread: bite from
infected tickTreatment: Antibiotic
Prevention: Tuck pants into socks; wear long –
sleeved shirt
TuberculosisSymptoms: fatigue, mild fever. Weight loss, night
sweats, coughSpread: Inhaling droplets
Treatment: AntibioticPrevention: Avoid
contact with people with active infection: vaccine (for those at high risk)
TetanusSymptoms: Stiff jaw and neck muscles, spasms, difficulty swallowing
Spread: Deep puncture wound
Treatment: Antibiotic; opening and cleaning
woundPrevention: Vaccine
Antibiotics and Bacterial Diseases
Strep ThroatSymptoms: Fever, sore throat,
swollen glandsSpread: Inhaling droplets; contact
with a contaminated objectTreatment: Antibiotic
Prevention: Avoid contact with infected people; do not share
utensils, cups, or other objects
Food PoisoningSymptoms: vomiting, cramps,
diarrhea, feverSpread: Eating food containing the
bacteriaTreatment: Antitoxin medicinesPrevention: properly cook and
store foods; avoid eating foods in rusted and swollen cans
Vaccines and Viral Diseases
InfluenzaSymptoms: high fever, sore
throat, headache, coughSpread: Contact with
contaminated objects; inhaling droplets
Treatment: bed rest; fluidPrevention: Vaccine
Hepatitis C
Symptoms: often no symptoms; jaundice (yellowing of the eyes and
skin) fatigueSpread: Contact with blood of an
infected personTreatment: Drugs to slow viral
multiplicationPrevention: Avoid contact with infected
blood
Vaccines and Viral Diseases
Chicken PoxSymptoms: fever; red, itchy
rashSpread: contact with the rash;
inhaling dropletsTreatment: Antiviral drugs (for
adults)Prevention: Vaccine
Acquired Immunodeficiency Syndrome (AIDS)
Symptoms: weight loss; chronic fatigue; fever; diarrhea; frequent infectionsSpread: sexual contact; contact with
blood; pregnancy, birth, and breastfeeding
Treatment: Drugs to slow viral multiplication
Prevention:Avoid contact with infected bodily
fluids
Fungi• Fungi are-Eukaryotic cells that have cell wallsHeterotrophs that feed by absorbing their
foodUse spores to reproduce
Size and labeling• Tiny unicellular yeasts• Larger multi-cellular
fungi• Largest is an
underground fungus as big a 1,000 football fields
• Hyphae – the branching, thread-like tubes that make up the bodies of multi-cellular fungi.
Although fungi are heterotrophs, they do not take food into their bodies as you do.
• Instead, fungi absorb food through hyphae that grow into the food source.
• Then, digestive chemicals ooze from the hyphae into the food.
• The chemical breaks down the food into particles small enough to be absorbed by the hyphae.
Fungi Reproduction
• Fungi usually reproduce by making spores. The lightweight spores are surrounded by a protective covering and can be carried easily through are or water to new sites.
• Spores are produced in the fruiting bodies.
• Even though fungi produce millions of spores, only a few will land where conditions are right for survival.
• Yeast- reproduce by budding
Most fungi reproduce both asexually and sexually.
Spores
• When there is adequate food and moisture.
Budding
• A small yeast cell grows from the body of a parent cell and then breaks away and lives on its own.
Sexual Reproduction
• When growing conditions become unfavorable, the hyphae of two fungi grow together and genetic material is exchanged.
Classification of Fungi
Club Fungi – Produce spores
Includes: mushrooms and
puffballs
Zygote Fungi – Produce spores
Includes: common fruit and bread molds, such as
Rhizopus
Sac Fungi – Produces spores
Includes:Yeasts, morels, and
truffles
Fungus’ Roles in Nature
EnvironmentalRecycling
Disease - Fighting
Fungus-Plant Root
Association
Disease-Causing
Food
Environmental Recycling
•Many are decomposers
Fungi and Food
•Yeasts help to make bread•We eat mushrooms and truffles
Disease – FightingFungi
•Penicillium produces a substance that kills bacteria
Disease – Causing Fungi•Many are parasites•Corn smut and wheat rust destroyed crops•Athlete’s Foot•Ring worms
Fungus-Plant Root Association
•Symbiotic relationship in which hyphae from a fungus absorbs food and water for the plant
Lichens•Symbiotic relationship between a fungus and either a bacteria or algae.•Useful indicators of pollution because they are very sensitive and die as pollution levels increase