Concept Formation
•Student Generated Data
•Sorted Data- group words based on perceptions of how the terms fit
together
•Determine Concept Labels
Concept Formation
Infectious Agents
Group Formation•Separate based on the following:
▫I received some form of technology over the Holidays!
▫I received money over the Holidays!▫I didn’t get anything over the Holidays!▫I received something better over the
Holidays!
Bell Work
How does bacteria affect your everyday life? Does bacteria impact your life positively,
negatively, or both?
Objectives
•Explain how the two groups of prokaryotes differ.
•Describe how prokaryotes vary in structure and function.
•Explain the role of bacteria in the living world.
Bacteria- True or False?
1. There can be up to 25 species of bacteria living in a single mouth.
2. A milliliter of saliva can contain as many as 40 million bacterial cells.
3. 80% of pathogens (bacteria & viruses) are spread by touch.
4. 400 more germs are present on a desk than on a toilet.
5. There are an estimated 75 to 100 trillion cells in the human body. There are more bacteria in your body than the number of cells in your body.
Let’s Do LunchWhat are bacteria and
how are they different from other
organisms?
Let’s Do LunchWhy are most bacteria
unable to live in our bodies?
Let’s Do LunchWhere do beneficial bacteria live in our
bodies?
Let’s Do LunchWhat are some
examples of how we use bacteria for
commercial purposes?
Let’s Do LunchWhy do you think
better hygiene led to a decrease in child
mortality?
Let’s Do LunchWhat kinds of niches do you think bacteria might occupy in the
ecosystem?
Let’s Do LunchWhy do you think
bacteria are so successful at living almost anywhere on
earth?
Let’s Do LunchWhat are some ways your body prevents
against bacterial infection?
Let’s Do LunchBiologists can now manipulate
the genetic code of many bacteria, engineering them to perform tasks they might not otherwise be able to do; what are some useful purposes for theses “designer” bacteria?
Prokaryotic Characteristics•Classification & Ecology•Cell wall•Size & Shape•Structure•Reproduction & Conjugations•Mutations & Antibiotics•Metabolism•Survival
Infectious Agents•Pathogen- any substance that is able to
cause disease in an individual.▫Bacteria: prokaryote microorganism that
causes tuberculosis, pneumonia, strep throat, and staph infections
▫Viruses: non-living infectious agent that causes flu, HIV/AIDS, herpes, chicken pox, and measles
* Other infectious agents: fungus, protists and worms.
I. Prokaryote Classification
•Once classified into Kingdom Monera ▫Lack of nucleus & membrane- bound
organelles•Now divided into two domains:
a. Domain Archaeab. Domain Bacteria (most common/affect
humans)
a. Domain Archaea• Live in extreme environments (called
extremophiles)Thermoacidophiles
Halophiles Methanogens
Environment
Hot (above 80C), acidic (pH
of 1-2)
Salty Anaerobes (can’t live in presence of
oxygen)
Environment Examples
Sulfur hot springs, ocean floor thermal
vents, volcanoes
Great Salt Lake,
Dead Sea
Sewage treatment
plants, swamps,
bogs, GI tract
b. Domain Bacteria•Bacteria (Kingdom Eubacteria) •Found everywhere except in extreme
environments •Have strong cell walls w/ peptidoglycan
(sugars & amino acids)
Clostridium tetani
Corynebacterium acneClostridium
botulinum
Diplococcus pneumoniae
Bacteria & Archaea Differences
Similarities Differences• Size• Prokaryotes• Have cell walls
• Different cell wall components▫ Bacteria have
peptidoglycan▫ Archaea lack
peptidoglycan• Different lipids in cell
membrane• Different proteins &
nucleic acid
I. Ecology of Bacteria
•Nutrient Cycling▫Decomposers: return nutrients to
environment▫Nitrogen fixation
•Normal Flora▫Harmless bacteria living in & on you
•Foods & Medicine•Disease Causing Bacteria
Objectives
•Explain how the two groups of prokaryotes differ.
•Describe how prokaryotes vary in structure and function.
•Explain the role of bacteria in the living world.
II. Cell Walls (AKA Capsule)•Determines the bacteria’s shape•All bacterial cells have cell walls
▫Eubacteria- have peptidoglycan▫Archae- lack peptidoglycan; different lipids
•Dies added to bacteria to identify two types:
▫w/ outer layer of lipid▫w/o outer layer of lipid
Technique = Gram Stain
Gram Stain•Large amount of peptidoglycan= dark
purple▫Called gram positive
•W/ a lipid layer; less peptidoglycan= light pink▫Called gram negativeGram Positive Gram Negative
Why does it
matter?
Gram negative bacteria are protected against most antibiotics & chemicals by
their outer cell wall. Only certain antibiotics can work against them.
Bell WorkWhat is the difference between Gram
Positive and Gram Negative bacteria? Which one would you
rather be infected by (you can’t tell me neither)?
III. ShapeCocci
(Spherical/Round)
Bacilli (Rod-shaped)
Spirilli (Spiral-shaped)
Arrangements of Cocci
Arrangements of Bacilli
Arrangements of Spirilli
Check Your Understanding!!
Gram positiveStaphylococci
Gram negativeStaphylobacilli or diplobacilli
Gram positiveStreptobacilli
Gram positiveStaphylobacilli
Gram negative Diplococci or Coccus
Gram negativeSpirili
Gram positiveStaphlococci
IV. Size•1-10 micrometers long, .7-1.5
micrometers wide•Favorable surface area-to-volume ratio
▫Nutrients & other substances can diffuse to all parts of the cell easily
1 micrometer= 1,000,000 of a meter
3-2-1 Exit Slip
•What are 3 things you learned about bacteria classification and structure?
•What are 2 things you found interesting?
•What is 1 question you still have?
IV. Prokaryote Structure•Microscopic•Unicellular•Organelles
▫No Nucleus or nuclear membrane▫Contains circular DNA- nucleoid▫Has cytoplasm, cell membrane & cell wall▫Has ribosomes▫No mitochondria or chloroplasts
Chromosomes•Genes are found on a large, circular
chromosome in the area called the nucleoid
•Many prokaryotes also have a smaller piece of DNA called a plasmid
Capsule•Complex sugar
layer around cell wall
•Capsule Function:▫ Prevents cell from
drying out▫ Helps cell attach to
surfaces ▫ Shelters cell from
WBCs & antibiotics
CapsuleCell Wall
Cytoplasmic Membrane
Movement•Some are stationary
•Some have flagella▫Help bacteria move towards light, higher oxygen concentration, or chemicals to survive
Flagella
Pili•Hair-like structures made of protein
•Function:▫Helps cells attach to
surfaces▫Serves as a bridge
btw. cells Copies of plasmids can
be sent across this bridge giving bacteria new genetic characteristics
Pili
V. Metabolism- How they obtain energya. Heterotrophs “other feeder”- can’t
synthesize own food; take in organic nutrients from the environment or other organisms▫Called Saprotrophs or saprobes- obtain
energy by decomposing dead organisms
Metabolism- How they obtain energy
b. Photoautotroph “light self-feeder”-carry out photosynthesis ; uses inorganic molecules (CO2 and H2O) to create organic molecules for food▫Ie. Cyanobacteria
Metabolism- how they obtain energyc. Chemoautotrophs “Chemical self
feeder”- break down/release inorganic compounds containing N or S in chemosynthesis▫Ie. Nitrogen Fixing Bacteria
Bell Work
You collected bacteria on Friday, what are ideal growing
conditions for the bacteria you collected?
Outbreak, Epidemic or Pandemic?
Bacteria Collection!
1. Work in a group of 3.2. Use a wax pencil to create
3 separate sections on the bottom of your agar plate.
▫ Label the area of contamination
▫ Include your class period & initials
3. Swipe your Q-tip and smear over your agar plate.
4. Open the agar plate only when you have your sample ready.
5. Tape the top lid to the bottom.
Bell WorkWhy is it important that a bacteria has a capsule as
well as pili?
Bacteria “Wanted Poster”
•You will research one bacterial pathogen and produce a “wanted poster”
•You must follow the given parameters for the project (use your rubric).
Think Pair ShareDiscuss the following questions with your
partner:1. What do you think is more dangerous to a developed
country: A viral epidemic or a bacterial epidemic? 2. Why do viral diseases spread more quickly than
bacterial diseases? 3. If a bacteria similar to the one that caused the
Bubonic Plague was introduced in downtown Dayton next week, how serious would it be? What would be done to combat the bacteria? What strategies would we use that weren’t available in the 14th century?
VI. Reproduction•Binary Fission- asexual reproduction▫Division of cell into two genetically identical cells
(Chromosome replicates)
(Original chromosome and new copy
separate)
(New plasma membrane and cell
wall form)
(two identical
cells)
Survival of Bacteria•Endospore- dormant bacterial cell
▫Protective capsule enclosing the cell’s DNA & cytoplasm
▫Cell stays inactive when conditions don’t favor growth
▫If conditions improve, the endospore become active & normal reproduction resumes
Activity on Bacteria Growth Rate
VII. Conjugation•Two cells attach
by a pili & exchange genetic info.▫Pili: acts as a “bridge”
transferring DNA from one cell to another
▫Plasmid: extra DNA molecule separate from nucleoid (circular DNA) that is transferred
1. Donor cell produces a pilus (singlular for pili)
2. Pilus attaches to recipient cell
3. An enzyme cuts the plasmid (break in the DNA strand)
4. Single DNA strand is transferred to the recipient cell & is incorporated into the nucleiod
5. Plasmids re-circle
VIII. Mutations
•Bacteria reproduce quickly & pop. grows rapidly ▫thus mutations can help bacteria survive
changing environments New gene combinations New bacteria characteristics Genetic diversity
Objectives1. SWBAT describe the steps in prokaryote
reproduction and conjugation.2. SWBAT explain how bacterial cells can
acquire new gene combinations through conjugation or from mutations as a result of rapid reproduction.
3. SWBAT describe how a population of bacteria can evolve to become antibiotic resistant.
Q: What are Antibiotics?A: Medicine that kills bacteria w/o
killing the human host
▫Some attack the cell wall (preventing it from forming properly)
▫Some target bacterial ribosomes Does not affect eukaryotic cells b/c antibiotics
don’t disrupt protein synthesis in human cells▫Some disrupt DNA reproduction
DNA can’t be reproduced/copied for new cells
Tracking the Spread of Antibiotic Resistance
Remember: the direct transfer of plasmids between bacterial cells can sometimes
transfer genes (via conjugation) for antibiotic resistance from one bacterium to another.
Represents a bacteria cell Represent plasmids
Round 11. You will simulate bacterial conjugation▫ w/o looking exchange plasmids (5 exchanges)
2. Count your yellow plasmids▫ Record data in “After Round 1 Exchanges” ▫ How many of you have yellow bands? tally▫ How many of you still don’t have any yellow bands? tally▫ Count how many yellow bands you have in your bag &
tally
Round 21. Repeat Bacterial Conjugation
▫ w/o looking exchange plasmids (5 exchanges)
2. Count your yellow plasmids▫ Record data in “After Round 2 Exchanges” ▫ How many of you have yellow bands? tally▫ How many of you still don’t have any yellow bands? tally▫ Count the number of bands you have in your bag & tally
Round 31. You will simulate antibiotic exposure ▫ Students w/o yellow plasmids will sit out of the round▫ w/o looking exchange plasmids (5 exchanges)
2. Count your yellow plasmids▫ Record data in “After Round 3 Exchange with Antibiotic
Exposure” ▫ How many of you have yellow discs? tally▫ How many of you still don’t have any yellow discs? tally▫ Count how many yellow discs you have in your bag &
tally
Let’s Do Lunch!•Proceed to
your next lunch date
•You will be given 5-7 min. to
answer the questions on your
worksheet
My Bacteria RapMy name is bacteria and I am prokaryotic
I don’t have a nucleus; it’s so chaoticI have a cell wall and I’m oh so small
A capsule, nucleoid, plasmid and THAT is allI replicate through binary fission; I start with one and go
through divisionCreating new offspring ensures my genetic provision
I come in spherical rod shaped and spiralNO I’m not Viral!
I go through metabolism to ensure my growthEither photo, chemo, or saprotrophAntibiotics might be the death of mebut if I mutate nothing stopping me!