2 VirusesViruses are NOT cells. A virus is an infectious agent made up of:a core of nucleic acid (RNA or DNA)a protein coat (capsid)Genetic material carries information for multiplicationHijacks biochemical machinery of hostcell to carry these processes outSo…viruses are NOT LIVING
3 Characteristics of life CELLVIRUSMade of cellsYESNOObtain & use energyGrow & developOnly inside a living cellReproduceRespond & adaptContain RNA or DNA
4 Re-Cap Viruses are NOT ALIVE. Viruses do not: Viruses do: Grow Have homeostasisMetabolizeViruses do:Infect cells and use the cell to make more virusesCause disease in many organisms
5 Structure of a virus Envelope (part of the protein coat) Capsid (part of the protein coat)Nucleic acid (either DNA or RNA)NUCLEICACIDCAPSID
6 Retrovirus A virus that contains RNA instead of DNA CAPSIDA virus that contains RNA instead of DNAHuman Immunodeficiency Virus (HIV) is a retrovirusHIV causes AIDSENVELOPERNA
7 Bacteriophage A virus that only infects bacteria CAPSID HEAD DNA TAIL FIBER
8 Ticking time bombs . . .Viruses do not reproduce by themselves. They invade a living cell and let the cell do the work for them.
9 Lytic CycleThe viral infection that rapidly kills the host cell is the lytic cycle.
11 Lysogenic CycleThe viral infection that enters a cell, remains harmless for a period of time (sometimes years), and then becomes harmful later is called the lysogenic cycle.
12 Lysogenic CycleIn the lysogenic cycle, the virus reproduces by first injecting its genetic material, indicated by the red line, into the host cell's genetic instructions.
13 Role of viruses All viruses act like parasites, harming the host cell. Viruses cause disease in every kind of organism—animals, plants, fungi, protists, and bacteria.
14 Some viral diseases HIV Measles Smallpox Influenza Chicken pox Common coldHerpesWartsMononucleosisMumps
15 HIVA retrovirusInfects human helper T-cells, which are associated with the immune system.Modes of transmission:Sexual contact with an infected personSharing needles with an infected personBlood transfusions (rare)Breast feedingEtc.
16 HPV Human Papilloma Virus Causes warts Most common STD in the United States80% of women by the age of 50 will have acquired some strain of genital HPV.HPV vaccine
17 Influenza (flu)Symptoms: body aches, fever, coughing, runny nose, fatigue, usually lasting about a week.Mode of transmissionAirborne (air droplets)People still die from influenza.
18 Viral diseases usually cannot be cured, but many can be prevented by Good hygieneImmunization
19 Bacteria are Prokaryotes. Prokaryotic Cells: Have no nucleusDo not have membrane bound organellesAre very smallOften have a flagellum for movement
20 Shapes of bacteria Bacteria are classified according to their shape: Round is called cocciRod shaped is called bacillaSpiral shaped is called spirilla
21 Where do they live?Bacteria are found in all environments
22 Role of bacteria Some bacteria are helpful Some bacteria are harmful E. coliYeastV.streptococciLactobacillusSome bacteria are harmfulS. pyogenesS. aureusY. pestis
23 Streptococcus Causes strep throat, pneumonia, and other infections. Named based on the shape and orientation of the bacteria.
24 StaphylococcusCause of staph infections that occur on the skin or in wounds. (ex. MRSA)But, Certain types of staph reside normally on the skin.
25 Diphtheria Swelling of the upper respiratory tract DPT Vaccine Can also infect skin cells.
26 How do bacteria cause disease? The release toxins that interfere with normal activity.
27 Prevention/Cure Vaccines to prevent. Antibiotics to cure (pennicillin, amoxycillin, etc).