viruses and bacteria
DESCRIPTION
Viruses and Bacteria. Differences between bacteria and viruses: http://www.youtube.com/watch?v=s-HThHRV4uo. http://www.youtube.com/watch?v=Rpj0emEGShQ- how the flu attacks your body. What makes a cell living and a virus non living!. What is a microbe? What is a pathogen?. - PowerPoint PPT PresentationTRANSCRIPT
http://www.youtube.com/watch?v=Rpj0emEGShQ- how the flu attacks your body
Differences between bacteria and viruses: http://www.youtube.com/watch?v=s-HThHRV4uo
What is a microbe? What is a pathogen?
Measles outbreak interactive map: http://www.cfr.org/interactives/GH_Vaccine_Map/#map
Bubonic plague is one of the deadliest pandemics in human history. It killed 30-60% of Europe’s population between 1348-1350 and took 150 years for Europe's population to recover.
Since AIDS was first recognized in 1981, it has led to the deaths of more than 25 million people, making it one of the most destructive diseases in recorded history.
Dairy product produced by fermentation of milk. People have been making and eating yogurt for atleast 5,500 years!
Global outbreak that began in Mexico, approximately 600,000 people infected world-wide.
Humulin was the first medication produced using modern genetic engineering techniques in which actual human DNA is inserted into a host cell. The host cells are then allowed to grow and reproduce normally, and due to the inserted human DNA, they produce a synthetic version of human insulin. Humulin can be used as a treatment for diabetes.
• Unicellular• Prokaryotic• Can be autotrophs or heterotrophs• Can be aerobic (uses oxygen) or anaerobic
• Can be motile or non-motile– For motility bacteria have cilia or flagella
Bacteria come in a wide range of shapes, sizes and colours!
Bacillus Bordetella Clostridium Escherichia
Spirulina StaphylococcusStreptococcus Salmonella
• Asexual reproduction is called binary fission
• Sexual reproduction is called conjugation
• Some bacteria also form endospores to survive harsh conditions and then germinate when conditions become favorable
1 bacterium1 bacteriumcan becomecan become1/2 million in1/2 million in6-7 hours6-7 hours
BinaryFission
Based on Based on Harvard Medical Harvard Medical School Family Health GuideSchool Family Health Guide
Conjugation- Exchanging genetic information in which a hollow bridge forms between two bacteria cells and genes are passed. This increases genetic diversity.
• We depend on Escherichia coli in our intestines to provide us with Vitamin K and B Complex vitamins.
• Lactobacillus bulgaricus found in cheese and yogurt. – Aids in the digestion of lactose by producing
the enzyme lactase.– Boosts the immune system
• Staphylococcus aureus-food poisoning when toxins are ingested
• Streptococcus pyogenes-causes strep throat—red spots on your throat are red blood cells the bacteria have destroyed
• Clostridium botulinum-produces toxins that cause paralysis for 4-6 months (botox injections are made of these toxins!!!)
• Pasteurization is used to remove bacteria from food
• Antiseptics can kill bacteria on tissues
• Antibiotics are used to kill bacteria that have entered the body
• Vaccines can prevent bacterial infections by stimulating the immune system
Some are AUTOTROPHS, meaning they make their own food from inorganic molecules.
Photoautotrophs which use light energy to convert carbon dioxide and water to carbon compounds and oxygen in a process similar to that used by plants.
Chemoautotrophs which uses energy directly from chemical reactions involving ammonia, hydrogen sulfide, nitrates, sulfur and iron.
Bacteria that needs oxygen to live= obligate aerobes.
Bacteria that can survive without oxygen=facultative anaerobes.
• A non-living parasite• Made of nucleic acids, proteins, and sometimes
lipids • Highly specific to the types of cells they infect
(bacteriophages are viruses that infect bacteria)• Do not obtain or use energy; Depends entirely
on a host to survive• Able to evolve
Inner core of nucleic acid, either RNA or DNA; containing information to make copies of the virus
Outer protein coat called a capsid Large viruses have envelope
surrounding capsid
A non-living, disease causing parasite that invades the cell.
It turns the cell into a virus making factory until it no longer needs the cell.
It then destroys the cell releasing new viruses to continue the cycle.
http://www.youtube.com/watch?v=Rpj0emEGShQ
Once attached to the plasma membrane of the host cell, the virus enters the cell and takes over its metabolism. Only then can the virus replicate.
http://www.tvdsb.on.ca/westmin/science/sbi3a1/Bacvirus/Virusrep.htm
1. The virus may inject its nucleic acid into the host cell like a syringe injects a vaccine into your arm
2. An enveloped virus enters a host differently. After attachment, the plasma membrane of the host cell surrounds the virus and produces a virus-filled vacuole inside the host cell’s cytoplasm. Then, the virus bursts out of the vacuole and releases its nucleic acid into the cell.
A typical lytic cycle takes about 30 minutes and produces about 200 new viruses.
The viral genes alter the host cell to make new viruses. The host cell uses its own enzymes, raw materials, and energy to make copies of viral genes that along with viral proteins are assembled into new viruses, which burst from the host cell, killing it.
Does not kill cell like lytic cycle does Begins like the lytic cycle. The virus
attaches to the host cell’s plasma membrane and its nucleic acid enters the cell.
Instead of immediately taking over the host’s genetic material, the viral DNA is integrated into the host cell’s chromosome.
Viral DNA that is integrated into the host cell’s chromosome is called a provirus.
A provirus may not affect the functioning of its host cell.
Every time the host cell reproduces, the provirus is replicated along with the host cell’s chromosome. Therefore, every cell that originates from an infected host cell has a copy of the provirus.
The lysogenic phase can continue for many years. However, at any time, the provirus can be activated and enter a lytic cycle. Then the virus replicates and kills the host cell.
Process explains the reoccurrence of cold sores, which are caused by the herpes simplex I virus.
Even though a cold sore heals, the herpes simplex I virus remains in your cells as a provirus. When the provirus enters a lytic cycle, another cold sore erupts.
Physical and emotional stress play a role in activating a provirus
Chicken pox and shingles
Alive
Capable of reproducing on its own
Capable of growing and developing during its ‘life’ cycle
Rhinoviruses cause the common cold HPV (Human papillomavirus) can
cause cervical cancer in women Herpes simplex viruses cause mouth
and/or genital sores, lesions, and ulcers.
Influenza viruses cause the flu HIV (Human Immunodeficiency
Virus) causes AIDS and weakens the immune systemhttp://www.youtube.com/watch?v=YSgkoldBNkI
Antibiotics DO NOT work on viruses. Most human viral infections can be
fought off by the immune system—boost the immune system with lots of water and rest.
Vaccines are preventative!!!
Vaccines will NOT cure you if you are already sick.
Vaccines stimulate the immune system to create antibodies that recognize a certain virus.
These antibodies patrol your body and if they recognize that virus…they call in reinforcements and your immune system goes to battle!
A virus recognizes and attaches to a host cell when one of its proteins interlocks with a molecular shape that is the receptor site on the host cell’s plasma membrane.
The recognition and attachment process is like two pieces of a jigsaw puzzle fitting together.
DNA viruses: herpes simplex virus (HSV)
Varicella zoster virus (VZV)
VZV: Chickenpox
VZV: Shingles
Re-activation of latent infection
Ebola hemorrhagic fever (Ebola HF) is a severe, often-fatal disease in humans and nonhuman primates
Appeared sporadically since its initial recognition in 1976.
Transmission arthropod bites.
No known treatment.
A retrovirus is an RNA virus that is replicated in a host cell via the enzyme reverse transcriptase to produce DNA from its RNA genome.
The DNA is then incorporated into the host's genome. The virus thereafter replicates as part of the host cell's DNA.
HIV is a retrovirus
The first virus to be identified was a plant virus, called tobacco mosaic virus
400 identified viruses that infect plants with 1000 different diseases
Cause stunted growth and crop losses
NOT classified because THEY ARE NOT ALIVE
Classified into the Kingdom Eubacteria or Archeabacteria
Non-living parasite Living
Cannot reproduce on their own (uses a host cell)
Can reproduce sexually or asexually
Contain DNA or RNA inside a protective coating
(capsid)
Contain circular DNA inside a cell membrane and cell
wall
Always pathogenic Can be helpful or pathogenic