Life Science Unit 2, Chapter 1

Virus A virus is a tiny particle that contains nucleic acid encased in protein

Virus

Virus is much smaller than a cell, 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! ShQ 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

Read Take a couple minutes and read page 89-90

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 move by flagellum (whip like tail) – Wiggling, air,wind, orgnamism, etc.

Many different types of bacteria – Round=cocci – Rod-shaped=bacillli – Spiral=spirella

Some bacteria live alone, others lie together Diplo=pair Staphylo=cluster Strepto=chain

Someone Read page 101, paragraphs 1-2

Bacteria reproduce asexually – One parent – Identical offspring – Some reproduce through splitting – Others through budding

Aerobic-bacteria that need oxygen Anaerobic-bacteria that do not )in fact many die in its presence)

If life conditions are not suitable for bacteria, some may form endospores – Protective capsules that allow bacteria to live for decades in a dormant state until conditions are favorable

Autotrophs Many bacteria are autotrophs- make their food through photosynthesis Some use hydrogen during photosynthesis and make sulfur instead of oxygen Bad smell from rotting food….

Heterotrophs Heterotrophs must eat from other organisms-which causes infections These are the ones that make us sick

Decomposers Get energy from breaking down dead organisms.

articles 11/ bacteria-mining_2.html 11/ bacteria-mining_2.html ating_bac.php ating_bac.php uses-bacteria/ uses-bacteria/ listeria-cancer-therapy/ listeria-cancer-therapy/ different-medical-uses-of-beneficial-bacteria.htm different-medical-uses-of-beneficial-bacteria.htm

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

Symbiosis

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 BQI BQI

Antibiotics are drugs used to kill harmful bacteria and other microorganisms They kill by interfering with bacterial cell functions

Someone read “overusing a good thing” on 110.

Bacteria and Disease Pathogens: disease causing bacteria/microorganisms They can cause diseases in humans, animals, and plants

Some of the diseases caused by bacteria include strep throat, cholera, and leprosy, pneumonia, tuberculosis, typhoid fever

Bacteria enter the body through natural openings (eyes, nose, mouth) or through breaks in the skin They destroy healthy cells, preventing the body from functioning properly

HThHRV4uo HThHRV4uo

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

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;-)