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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, 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 cellsCannot reproduce/mutate outside of hostCan survive dormant outside of cells for yearsViruses resemble their host cells
THE FLU!
• http://www.youtube.com/watch?v=Rpj0emEGShQ
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
• http://news.nationalgeographic.com/news/2008/11/081105-bacteria-mining_2.html
• http://www.dvice.com/archives/2011/12/rock_eating_bac.php
• http://www.livestrong.com/article/29090-good-uses-bacteria/
• http://medcitynews.com/2013/11/biotech-uses-listeria-cancer-therapy/
• http://www.wisegeek.com/what-are-the-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 paragraphs2. 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
• 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
• http://www.youtube.com/watch?v=s-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
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
Protists
• Many are one celled• All are aquatic ( salt water, fresh
water, watery tissues of other living things)• Some are helpful parasites (like
intestinal bacteria) • Others are harmful
•Some are autotrophs, some are heterotrophs•Some are both!
Plantlike Protists
• 3 Types:–1. Dinoflagellates–2. Euglenas–3. Diatoms
Plantlike Protists
• Dinoflagellates are one-celled ocean organisms living as plankton• Plankton are microscopic
organisms living near the surface of the water• Some of them glow!
Glowing Plankton
http://www.youtube.com/watch?v=uUbIWqiynBY
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
Red Tide
Euglenas
• Both autotrophs and heterotrophs• 3 common features:–1. Pouch with two flagellas, short
and long–2. Chloroplasts–3. Reddish eye spot to determine
photosynthesis
Diatoms
• Live in fresh water, salt water, or soil• They can feed both plankton and
Whales!• Make up 25% of all
photosynthesizing life on Earth• Produce at least 25% of the air we
breathe!
• Diatoms have glass like shells•When they die the shells are
left behind and used for polishing agents and uses that reflective
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
• Have tiny hair like parts that move in rhythm• They detect food
to eat• One type of Ciliate
is a paramecium