Notes 4/15. Chapter 16 Bacteria and Viruses Did you know?!!?!?!? –Bacteria are small living things –It would take a million to cover a pin head (another.

Notes 4/15

Chapter 16Chapter 16Bacteria and VirusesBacteria and Viruses

Did you know?!!?!?!?Did you know?!!?!?!?

–Bacteria are small living thingsBacteria are small living things– It would take a million to cover a It would take a million to cover a

pin head pin head (another way to think about a (another way to think about a million of something is to think of the million of something is to think of the characters (letters punctuation) in a 500 characters (letters punctuation) in a 500 page book, or that it would take you 12 days page book, or that it would take you 12 days to count to a million non- stop)to count to a million non- stop)

DID YOU KNOW!?!?!?!?DID YOU KNOW!?!?!?!?

–Bacteria live on/around; water, air, Bacteria live on/around; water, air, people, food, soil, animalspeople, food, soil, animals

–Some bacteria are good and some Some bacteria are good and some are badare bad

–Bacteria grow best when they have Bacteria grow best when they have food, warmth, water and timefood, warmth, water and time

–Bacteria grow best within a Bacteria grow best within a temperature of 8°C and 63°Ctemperature of 8°C and 63°C

Bacteria grow well on certain types of food such as;Bacteria grow well on certain types of food such as;• Meat• Chicken• Fish• Cooked Rice• Cooked Pasta• Milk• Cheese• Eggs• Meat pies• Cream• Gravy

ProkaryotesProkaryotes

Or 100 Trillion Friends ThatOr 100 Trillion Friends That You Didn’t Know You HadYou Didn’t Know You Had

Bacteria

• Were once included in Kingdom Monera (which doesn’t exist anymore)

• Now 2 separate groups:

–Archeabacteria

–Eubacteria

Archaebacteria—cell wall lacks peptidoglycan--contains membrane lipids (fats) not found in any other living things.

--Live in extremely harsh environments Ex.-Oxygen-free locations (thick mud, digestive tract of animals, Great Salt Lake, hot springs, etc)

Biologists refer to Archeaebacteria as “extremophiles” (Lovers of the extremes)

Thermophiles: Heat lovers; live in hot springs of Yellowstone National Park or deep sea ocean vents

Halophiles: Salt lovers; thrive in areas like Great Salt Lake

Methanogens: Oxygen free environments; such as mud at bottom of lakes and swamps where they produce “swamp gas” (methane)

Eubacteria—usually surrounded by a cellwall (made of peptidoglycan—a carbohydrate)that protects the cell from injury and determines its shape

--As a result (of the protective cell wall), these bacteria can live almost anywhere. (fresh water, salt water, on land, on or in human body, etc)

E. coli, a Typical Eubacterium

DNA

PiliFlagellum

Bacilli: rod-shaped prok’s

Cocci: Spherical prok’s

Spirilla: Spiral and corkscrew-shaped prok’s

Prokaryotes are identified by:

1. SHAPE

2.Cell Walls

TwoTwo different kinds in Eubacteria.•Completely composed of peptidoglycan (thick) •Less peptidoglycan and an additional outer membrane (thin)

How can you tell the difference??Gram Staining: Test with violet and pink dyes.

Under a microscope, if the bacteria is purplepurple they are Gram-Positive;Gram-Positive; This is because of extra thick cell wall (lots of peptidoglycan) If bacteria is pinkpink it is Gram-negativeGram-negative.. (not a lot of peptidoglycan)

Gram Staining Procedure

How is Gram Staining Useful?

• Doctors use Gram staining to identify bacteria in order to prescribe the correct antibiotics. Some antibiotics only work against Gram-Gram-positive bacteriapositive bacteria.

3. Movement

Some move, some don’t (non-motile)

If they do move, how do they move?

-flagella (might be scattered all over the cell, or in one area)-pili (short projections that help bacteria stick to each other and to surfaces)-“spiral” or “snake” forward-glide a slime like material they secrete

Metabolic DiversityWays bacteria obtain energy!

(modes of nutrition) Chemoheterotrophs-must take in organic molecules for both energy and supply of carbon

Photoheterotroph-perform photosynthesis forenergy, but must take in organic compoundsas a carbon source

Photoautotrophs-use light energy to convertCO2 and H2O to carbon compounds and O2

Chemoautotrophs-make organic carbon molecules from CO2 (don’t require light)

Growth and Reproduction- Bacteria will divide very quickly if their environment is favorable

- Binary Fission: Asexual reproductionAsexual reproduction

- offspring are genetically identical to parent - no new genetic combinations - under ideal conditions can occur every 20 min

- creates large numbers of bacteria in a short time

http://www.youtube.com/watch?v=5Xi2Nc1UicQJeff Simmonds - The Multiplication Song

• Each spot represents Each spot represents

a single bacteriala single bacterial

cell that reproduced cell that reproduced

by binary fission toby binary fission to

produce millions ofproduce millions of

genetically identicalgenetically identical

cells.cells.

• Genetically identical,Genetically identical,

good or bad?good or bad?

Exchanging Genetic InformationExchanging Genetic Information• Bacterial cells need to be able to exchange genetic Bacterial cells need to be able to exchange genetic

information information

- creates new genetic combinations which increases the ability - creates new genetic combinations which increases the ability of the bacteria to surviveof the bacteria to survive

• Bacteria have 3 methods for exchanging DNABacteria have 3 methods for exchanging DNA

-Transduction-Transduction – viruses carry DNA from one bacterial – viruses carry DNA from one bacterial cell cell to anotherto another

-Transformation-Transformation – bacteria can absorb – bacteria can absorb ““nakednaked”” DNA DNA released by dead bacteria from released by dead bacteria from the the environmentenvironment

- - ConjugationConjugation – two bacteria join at a conjugation – two bacteria join at a conjugation bridge, bridge, one bacteria passes on a one bacteria passes on a copy of its plasmid or copy of its plasmid or

chromosomechromosome

Exchanging Genetic InformationExchanging Genetic Information

Read in your book about Transformation, Read in your book about Transformation, Conjugation, Transduction (pg. 364-Conjugation, Transduction (pg. 364-365)365)

Summarize each and draw a picture to help you explain what is occurring… Be CreativeBe Creative!

Don’t just copy drawings in book!