Presentation is loading. Please wait.

Presentation is loading. Please wait.

Life Science Unit 2, Chapter 1. Virus A virus is a tiny particle that contains nucleic acid encased in protein.

Similar presentations

Presentation on theme: "Life Science Unit 2, Chapter 1. Virus A virus is a tiny particle that contains nucleic acid encased in protein."— Presentation transcript:

1 Life Science Unit 2, Chapter 1

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

3 Virus

4 Virus is much smaller than a cell, 25-250 nanometers (one-billionth of a meter) About 300 x smaller than a cell

5 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

6 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


8 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

9 Viral Infection Viral infection: penetration of a virus or its nucleic acid into a host cell

10 Read Take a couple minutes and read page 89-90

11 Get started on your notes from yesterday Try to finish in about 20 minutes;-)

12 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”

13 Bellwork What is the most interesting thing you discovered about your virus?

14 Bacteria Bacteria are one celled, Have a protective outer wall Have a jelly-like cytoplasm with enzymes


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

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



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


22 Someone Read page 101, paragraphs 1-2

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

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

25 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

26 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….

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

28 Decomposers Get energy from breaking down dead organisms.

29 articles 11/081105-bacteria-mining_2.html 11/081105-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

30 Bacteria is both vital for, and harmful to all life on this planet Give an example of each

31 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

32 Relationships Symbiosis-one organism lives on/near/inside another organism and at least one benefits

33 Symbiosis

34 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?

35 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

36 Good bacteria BQI BQI

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

38 Someone read “overusing a good thing” on 110.

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

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

41 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

42 HThHRV4uo HThHRV4uo

43 Other bacteria produce poisons called toxins Sometimes toxins are released after bacteria die Other bacteria cause food poisoning, infections, and blood poisoning

44 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

45 Antibiotics are the primary method for killing bacteria

46 Food and Bacteria Most foods are spoiled by bacteria When bacteria break down food they can make it taste bad or even poison it!

47 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

48 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

49 Refrigerators and freezers also slow down the growth of bacteria.

50 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;-)

51 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

52 Share Would Someone Like to Share Their Journal Entry?

53 Protists A protists are organisms that have a nucleus, but is not an animal, plant or fungus. Some are microscopic, others are not


55 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

56 Some are autotrophs, some are heterotrophs Some are both!

57 Plantlike Protists 3 Types: – 1. Dinoflagellates – 2. Euglenas – 3. Diatoms

58 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!

59 Glowing Plankton nBY

60 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

61 Red Tide

62 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


64 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!

65 Diatoms have glass like shells When they die the shells are left behind and used for polishing agents and uses that reflective


67 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

68 Brown Algae Chemical extracts from brown algae are added to salad dressing to keep them smooth and thick.

69 Red Algae Most seaweed is red algae Carrageenan (chemical derived from red seaweed) is used to stabilize creamy food products

70 Golden Algae Can be autotrophs or heterotrophs Eat bacteria and one-celled protists

71 Animal Like Protists Animal like because: they are heterotrophs, most can move, don’t have a cell wall

72 Amoebas Animal-like protists Eat and move with a pseudopod: An extension of cytoplasm “false foot”

73 Amoebas Some are parasites One type causes dysentery: A disease of the large intestine with diarrhea and pain

74 Ciliates/Paramecium H ave tiny hair like parts that move in rhythm They detect food to eat One type of Ciliate is a paramecium

Download ppt "Life Science Unit 2, Chapter 1. Virus A virus is a tiny particle that contains nucleic acid encased in protein."

Similar presentations

Ads by Google