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BACTERIA What are Monerans? Monerans are believed to have existed longer than any other life form on Earth Most monerans are types of BACTERIA What Do We Know About Bacteria? Unicellular organisms: One celled organisms Do not have a true, membrane bound nucleus Can be found almost everywhere Some bacterial are bad for you Some bacterial are good for you Some bacterial will not affect your health at all What Do Bacterial Look Like? Bacterial are usually one of three shapes: Rods Spheres Spirals How Do Bacterial Reproduce? Bacterial reproduce asexually Reproduce by dividing in half Binary Fission Bacterial split into two cells Each cell gets an exact copy of the DNA Some bacteria can actually reproduce every 20 minutes Anything Else about Bacteria Some contain Chlorophyll and make their own food, we call them Autotrophs Others can’t make their own food, we call them Heterotrophs Some can get their energy from chemicals such as: Ammonia and Sulfur Others live in odd place like: Deep sea vents Antarctica Hot Springs What is Their Function? Help decompose dead things Live in animals’ digestive system to digest food They may cause diseases and they are called pathogens Some can be killed off with antibiotics which stop their reproduction process. Others can be prevented by vaccination, a way of killing bacteria to help the body protect itself against the live bacteria Used in the food making process Used to make artificial snow at ski resorts Name Something Else that Causes Diseases and Sickness, besides Bacteria or “Germs.” VIRUS! Properties of viruses • no membranes, cytoplasm, ribosomes, or other cellular components • they cannot move or grow • they can only reproduce inside a host cell • they consist of 2 major parts - a protein coat, and hereditary material (DNA or RNA) • they are extremely tiny, much smaller than a cell and only Review of DNA • Shape of a double helix •Base pairs held together by hydrogen bonds (weak) •Repeating units of nucleotides Adenine <-> Thymine Guanine <-> Cytosine Parasitic Nature •Obligate intracellular parasites •Specific to their hosts (human, dog, some can cross species) •They can only attack specific cells , the common cold is a virus that specifically attacks cells of the respiratory track (hence the coughing and sneezing and sniffling). •HIV specifically attacks white blood cells Bacteriophage a virus that infects bacteria Viral Reproduction Lytic cycle = reproduction occurs, cells burst Lysogenic cycle = reproduction does not immediately occur (dormancy) Virulent = viruses that undergo both cycles Viruses multiply, or replicate using their own genetic material and the host cell's machinery to create more viruses. Viruses cannot reproduce outside of the host. 1. 2. 3. 4. 5. Attachment Penetration - the virus is engulfed by the cell (Cell can enter Lysogenic or Lytic Cycle) Biosynthesis - viral components are made(protein coat, capsid, DNA/RNA) Maturation - assembly of viral components Release - viruses leave host cell to infect new cells(often destroys host) Retroviruses -- RNA viruses that have a DNA stage Human Immunodeficiency Virus - causes AIDS Retrovirus (RNA inside a protein coat) Reverse Transcriptase makes DNA from the virus RNA DNA inserts into host DNA Proteins are assembled from the DNA code Viruses assembled from the proteins Viruses released from the cell Emerging Viruses Emerging Viruses illnesses not previously known: AIDS, West Nile Virus, SARS, Ebola, Bird Flu Could be mutations of known viruses Could be viruses exposed when new areas were developed Could have jumped species How Do Vaccines Work? Once you have gotten a virus, such as chicken pox, your body develops the immunity to that virus. 2. Vaccines are made by growing a weakened or killed form of the virus (often grown in eggs) 3. This form of the virus is injected into a person's body, which causes an immune response, and immunity to the virus. 1.