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