Bacteria Viruses Biology Science Department Deerfield High School

Bacteria & Viruses Biology Science Department Deerfield High School

QUIZ TIME Biology Science Department Deerfield High School (30 MIN)

Staphylococcus aureus commonly causes boils and soft-tissue infections as well as more serious conditions such as pneumonia or bloodstream infections. According to the Centers for Disease Control and Prevention (CDC), 20 -35% of adults and children in the United States are positive for the bacteria but do not cause illness. Staphylococcus aureus colonization usually occurs in the armpit, groin, genital area, and, most frequently, the inside of the nose. Most infections occur through direct physical contact of the staph bacteria with a break in the skin (cut or scrape) or during contact with inanimate objects (such as clothing, bed linens, or furniture) soiled with wound drainage. The most common transmission location are in schools and hospitals. Biology Science Department Deerfield High School Warm Up

Analyze the graph: 1. Which location has the highest occurrence of resistance? 2. Based on the graph, make an inference about why penicillin resistant S. aureus is greater in one location compared to another. 3. Why did methicillin resistance lag behind penicillin resistance? Based on the trend seen with penicillin, what would you expect to see happen with methicillin? Biology Science Department Deerfield High School

What do you already know? § What are the differences between viruses and bacteria? § Are all bacteria harmful? § When you get a cold, should you take an antibiotic to help you get better? § What’s the best and easiest thing to do to avoid getting sick? Biology Science Department Deerfield High School

Bacteria § Bacteriology is the study of bacteria § Bacteria are prokaryotic, unicellular organisms containing DNA and ribosomes. § Bacteria have ALL the characteristics of living things. § Bacteria have the greatest percentage of the biomass on Earth! Biology Science Department Deerfield High School

Bacterial Structure § Basic structure of bacteria: Peptidoglycan* Cell Ribosom Cell wall membrane e Flagellum Biology Science Department Deerfield High School DNA Pili

Bacteria § A rather vocal minority (less than 1%) of bacteria cause disease in humans, animals, and plants. § Bacteria can cause a variety of diseases: – Food Poisoning – Tuberculosis – Cholera – Syphilis – Ulcers – Strep Throat Biology Science Department Deerfield High School – Scarlet Fever – Whooping Cough – Bacterial Meningitis – Pneumonia – Leprosy – Tetanus VIDEO CLIP: Understanding Bacteria

Viruses § Virology is the study of viruses § Viruses are “biological entities” containing either DNA or RNA that require another cell to survive. § Viruses have some, but not all, of the characteristics of life. *So are viruses living or non-living? * § Viruses seem to exist only to make more viruses! Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Viral Structure § All viruses have the same basic structure: Capsid (Protein coat) Surface Markers Biology Science Department Deerfield High School Nucleic acid core (DNA or RNA)

Biology Science Department Deerfield High School

How Do Viruses Work? § In order to replicate and make copies of itself, viruses need a host cell. Any living cell can become a host cell (human, animal, plant, and even bacterial cells!) § Without a host cell, viruses cannot function (i. e. are harmless!) § Although any cell can theoretically become a host cell, specific viruses will only infect specific cells (EX: HIV will only infect human T cells, a part of your immune system) Biology Science Department Deerfield High School

Transmission of Viruses § Respiratory transmission – Influenza A virus § Fecal-oral transmission – Enterovirus § Blood-borne transmission – Hepatitis B virus § Sexual Transmission – HIV § Animal or insect vectors – Rabies virus Biology Science Department Deerfield High School

How Do Viruses Work? § Attach: The capsid of the virus binds to receptor proteins on the surface of a host cell, tricking the host cell into thinking it’s not a foreign invader. § Inject: The virus then injects its genetic material (DNA or RNA) into the host cell. § Assemble: The viral genes are expressed, turning the host cell into a virus-making factory. § Repeat: The host cell eventually bursts, releasing the hundreds of newly formed viruses to infect VIDEO CLIP: How Viruses Work surrounding cells! Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Viruses § Viruses can cause disease in humans, animals, plants, and even bacteria! § Viruses can cause a variety of diseases: – Common cold – Hepatitis A, B & C – Herpes – Mononucleosis – Warts – Chickenpox Biology Science Department Deerfield High School – Polio – Influenza – Mumps – Measles – Viral Meningitis – AIDS VIDEO CLIP: Viral Disease

Bacteria Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

Acute Virus Infection Amount of virus Symptoms Virus Biology Science Department Deerfield High School Time

Poliovirus Biology Science Department Deerfield High School

Poliovirus Properties of the virus § Enterovirus. § Possesses a RNA genome. § Transmitted by the faecal oral route. § Cause of gastrointestinal illness and poliomyelitis. Biology Science Department Deerfield High School

Protection § There a few big ways to protect yourself against pathogens (disease causing agents) – Antibiotics (drugs to kill bacteria) – Antivirals (drugs to treat viruses) – Vaccination (using your body’s own immune system to preemptively guard against attack) Biology Science Department Deerfield High School

Antibiotics § Antibiotics can only be used to treat bacterial infections! § Target specific structures on bacteria to kill them. § First made from a fungus (penicillin), now most are made artificially. § Unfortunately, antibiotic resistance (where the antibiotic doesn’t kill the target bacteria anymore) is becoming a major problem. Biology Science Department Deerfield High School

Antivirals § Antivirals can only be used to treat certain viral infections! § Does not “kill” or disarm the virus permanently; only shortens symptoms by 1 -2 days. § Usually only prescribed to patients with life threatening symptoms or those that have a greater chance of developing complications (because of their age or they have a high-risk medical condition). § Just like antibiotics, there is evidence of antiviral resistance too! Biology Science Department Deerfield High School

Vaccination § Vaccines can only be used to prevent infections (both viral and bacterial) from leading to disease. § “Trick” your immune system to make antibodies that destroy foreign “bodies” or particles (such as bacteria and viruses). Your body remembers how to make these antibodies when the real thing invades. § Made from a weakened virus, inactivated virus, or by using only part of the virus/bacteria itself. VIDEO CLIP: Vaccination Biology Science Department Deerfield High School

Biology Science Department Deerfield High School

To Review. . § What are the differences between viruses and bacteria? § Are all bacteria harmful? Explain. § When you get a cold, should you take an antibiotic to help you get better? Why? § What’s the best and easiest thing to do to avoid getting sick? Biology Science Department Deerfield High School

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Bacteria Virus Both Biology Science Department Deerfield High School