Biology Science Department Deerfield High School What makes us sick?  Bacteria  Virus  Fungi  Parasites  Other

Biology Science Department Deerfield High School Today, we are going to talk about bacteria!  Bacteriology is the study of bacteria  Bacteria have the greatest percentage of the biomass on Earth!

Biology Science Department Deerfield High School Characteristics of Bacteria  They are prokaryotic. 2. They are unicellular. 3. They have DNA and ribosomes. So, are they living? How do you know?

Biology Science Department Deerfield High School Bacterial Structure  Basic structure of bacteria: Ribosome Pili DNAFlagellum Peptidoglycan* Cell wall Cell membrane

Biology Science Department Deerfield High School Bacterial Structure  Bacteria have three distinct shapes: spherical (cocci) rod-shaped (bacilli) spiral (spirilla)

Biology Science Department Deerfield High School Bacteria, all bad?  Bacteria have a variety of important uses: – Help make interesting food – Decompose organic matter – Nitrogen fixation – Human health – Biotechnology

Biology Science Department Deerfield High School Bacteria  Less than 1% of bacteria cause disease in humans, animals, and plants.  Bacteria can cause a variety of diseases: – Food Poisoning– Scarlet Fever – Tuberculosis– Whooping Cough – Cholera– Bacterial Meningitis – Pneumonia – Ulcers– Leprosy – Strep Throat– Tetanus

Biology Science Department Deerfield High School How Do Pathogenic Bacteria Work?  Bacteria produce disease in one of two ways:  Using cells for food: The bacteria break down healthy cells for food, destroying tissues  Releasing toxins: The bacteria produce a toxin (poisonous protein) that is released into the bloodstream where it can travel throughout the body, disrupting normal activity and damaging tissues

Biology Science Department Deerfield High School Biology Science Department Deerfield High School Exit Ticket:  What are the characteristics of bacteria?  What kingdom do bacteria belong?  Are they living? Why or why not ?  Describe 2 examples of how bacteria can be helpful?  How do bad bacteria make you sick?

Biology Science Department Deerfield High School 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: Nucleic acid core (DNA or RNA) Capsid (Protein coat)

Biology Science Department Deerfield High School

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 Lytic Cycle

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 surrounding cells! VIDEO CLIP: How Viruses Work

Biology Science Department Deerfield High School Lysogenic Cycle

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– Polio – Hepatitis A, B & C– Influenza – Herpes– Mumps – Mononucleosis– Measles – Warts– Viral Meningitis – Chickenpox– AIDS VIDEO CLIP: Viral Disease

Biology Science Department Deerfield High School How the Lytic and Lysogenic Cycles Work Together!!!

Biology Science Department Deerfield High School Exit Ticket  Are Viruses alive? Justify your answer.  What are viruses made of?  Explain the basic difference between the lytic and lysogenic cycle.  What are the steps of the lytic cycle?  Name 2 viral diseases.

Biology Science Department Deerfield High School Protection  There are 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?

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Biology Science Department Deerfield High School Bacteria Virus Both