Virus is much smaller than a cell, 25-250 nanometers (one-billionth of a meter) About 300 x smaller than a cell
Alive or not? Scientists disagree about whether viruses are living things or not. They can reproduce (but only by infecting a living cell) They can mutate They have RNA, DNA, and nucleic acids
Viruses are not made of cells Cannot reproduce/mutate outside of host Can survive dormant outside of cells for years Viruses resemble their host cells
THE FLU! http://www.youtube.com/watch?v=Rpj0emEG ShQ http://www.youtube.com/watch?v=Rpj0emEG ShQ
Virus Reproduction Viruses want to reproduce! Because the virus is so much like their host cells, they can survive only in those hosts Each virus works only in certain cells and infects only certain species on bacteria, plants, or animals
Viral Infection Viral infection: penetration of a virus or its nucleic acid into a host cell
Get started on your notes from yesterday Try to finish in about 20 minutes;-)
Summarize Make sure you include: 1: the process by which a virus infects bacteria (what its called and the process) 2: How viruses infect animal and plant cells 3: Retroviruses and an example 4: The “basic pattern of virus infection”
Bellwork What is the most interesting thing you discovered about your virus?
Bacteria Bacteria are one celled, Have a protective outer wall Have a jelly-like cytoplasm with enzymes
Bacteria is both vital for, and harmful to all life on this planet Give an example of each
Methanogens Bacteria that make methane Anaerobic bacteria Live in sewage, sediment, intestines, etc. Helps animals digest food Methane produced is essential to our atmosphere Too much is harmful, though
Relationships Symbiosis-one organism lives on/near/inside another organism and at least one benefits
Bacteria and Humans Read the article and do the following: 1.summarize your article in no less than 2 paragraphs 2. What did you learn about the other uses of bacteria?
Helpful and harmful bacteria Bacteria in food can make us sick Nitrogen-fixing bacteria helps to fertilize crops Bacteria is involved in much of the food we eat – Vinegar, cheese, buttermilk, sour cream, soy sauce, pickles, yogurt
Good bacteria http://www.youtube.com/watch?v=6FPy5m1- BQI http://www.youtube.com/watch?v=6FPy5m1- BQI
Antibiotics are drugs used to kill harmful bacteria and other microorganisms They kill by interfering with bacterial cell functions
Other bacteria produce poisons called toxins Sometimes toxins are released after bacteria die Other bacteria cause food poisoning, infections, and blood poisoning
Some bacteria may live in a healthy person’s body and be harmless until that person’s resistance is low When resistance is low your body can’t fight bacteria as quickly as they reproduce. Thats why you get sick easier when you are tired or stresses
Antibiotics are the primary method for killing bacteria
Food and Bacteria Most foods are spoiled by bacteria When bacteria break down food they can make it taste bad or even poison it!
Protecting Our Food Canning: food is heated to kill bacteria and sealed in airtight containers Preservatives: Chemicals added to foods slow the growth of bacteria and mold
Protecting Our Food Freeze-Drying: most bacteria need moisture and oxygen to grow. – Freeze-drying removes all the moisture and then it is sealed in an airtight container Pasteurization: the process of heating a liquid to kill harmful bacteria
Refrigerators and freezers also slow down the growth of bacteria.
Activity Read the “Focus on Alexander Fleming” Then, write a journal entry as if you were Alex. Tell about your discovery, how you found it, what brought you to science, and how your discovery will change science! Minimum 4 paragraphs, 5 sentences each;-)
When you finish Complete the all of the “review” questions in Chapter 2, Bacteria (pages 100, 104, 107, 110,115) This will be homework if not completed in class
Share Would Someone Like to Share Their Journal Entry?
Protists A protists are organisms that have a nucleus, but is not an animal, plant or fungus. Some are microscopic, others are not
Too much of a good thing Under certain conditions dinoflagellates multiply too rapidly and create a “Red Tide” They can actually range in color They can produce toxins that make fish and people sick
Algae-Multicellular Protists Some reproduce through binary fission, others reproduce sexually All contain chlorophyll for photosynthesis Green algae are the most common They store more than a billion tons of carbon, taken from the air during photosynthesis
Brown Algae Chemical extracts from brown algae are added to salad dressing to keep them smooth and thick.
Red Algae Most seaweed is red algae Carrageenan (chemical derived from red seaweed) is used to stabilize creamy food products
Golden Algae Can be autotrophs or heterotrophs Eat bacteria and one-celled protists
Animal Like Protists Animal like because: they are heterotrophs, most can move, don’t have a cell wall
Amoebas Animal-like protists Eat and move with a pseudopod: An extension of cytoplasm “false foot”
Amoebas Some are parasites One type causes dysentery: A disease of the large intestine with diarrhea and pain
Ciliates/Paramecium H ave tiny hair like parts that move in rhythm They detect food to eat One type of Ciliate is a paramecium