Scribe Post for Thursday, October 20, 2011

Today in Class...

• finished and went over UP. 33
  


• finished bacteria notes
  


• recorded data in both bacteria labs (UP. 19-25)

Today's Homework...

• finish lab analysis (UP. 19-25)
  


• read textbook Chapter 24 and finish note sheet
  


• work on disease script---due on Halloween


• work on spice lab (Up.39-42)

UP. 33 Antibiotics

III. Analysis

1. Which of the antibiotics would you use to prevent the growth of B. subtilis?

Neomycin.

2. Which of the antibiotics would you use to prevent the growth of E.coli?

Tetracycline.

3. Are both organisms equally sensitive to each of the antibiotics used? Explain.

No because there are size differences in the zone of inhibitions.

4. Which of the two organisms is more sensitive to antibiotics in general?

B. subtilis.

5. If you wanted to inhibit both organisms with one antibiotic, which one would you use?

Aureomycin.

6. If E.coli is beneficial and B.subtilis is harmful and you were infected with both, which antibiotic would you choose?

Neomycin.

7. In general, what can you conclude about bacteria and antibiotics from this experiment?

Antibiotics are specific at which bacteria they cure the best.

8. What feature does this experiment lack which it should have included?

A control group.

9. How would you correct this mistake?

Add a paper disk with no antibiotic in both petri dishes.

Important Information in the Notes

Power of Antibiotics

• Zone of Inhibition---area in which the growth of bacteria is prevented or inhibited by an antibiotic or other substance; measurable

Koch's Postulates

1. The same, specific pathogen must be identified in each host that has the disease.
   


2. The pathogen must be isolated from a host and grown in a pure culture, one in which no other kinds of cells are present.



3. The original disease must be produced in experiment hosts that are inoculated with the pathogen from the pure culture.



4. The same pathogen must be isolated from the experimental hosts after the disease develops in them.

Bacteria Labs

How Common are Bacteria and How Quickly Do They Reproduce?(UP. 19-22)

observe the agar surface and count the number of colonies

• without removing the cover
  


• white, creamy, or yellow dots


• white fuzzy colonies are molds


• each colony represents what was one original cell placed on agar surface


• record the numbers in the data table an share with your partner
  

Using Antibiotics to Stop Bacterial Growth (UP. 23-25)

look for zones of inhibitions surrounding the paper disks and measure the diameters in mm

• do not open the petri dish
  


• record the measurements in the data table and share with your partner

Thank you for reading,

see you tomorrow in class!

Helen

Next Scribe: ***Melissa***

Wednesday, October 19, 2011

Today in class:

- Passed back the Understanding Bacteria worksheet

- Did two labs on pgs. 19-25

- The first one was How Common Are Bacteria and How Quickly Do They Reproduce?

- The second one was Using Antibiotics to Stop Bacterial Growth

- In this experiment we’re using the bacteria Bacillus subtilis.

- Then we took notes on Prokaryotes and bacterial cell and reproduction (pgs. 8-11)

Homework:

- You can start answering the analysis questions on pg.21 and 25. For some of these questions, you don’t need to know the results of the experiment in order to answer them.

- Read and highlight key points on Unit Packet p.27-29

- Fill in Unit Packet p. 31-32 (use text/internet)- DUE FRIDAY 10/21

-Work on disease project due Monday 10/31

-Work on Spice Lab due by 10/25

1^ST LAB

- You need a sterile petri dish w/agar, a wax glass marking pencil and tape.

- First divide your petri dish into quarters and mark the outside bottom surface and number the sections 1-4.

- Next, select 3 objects to test for the presence of bacteria. Each object or surface selected is to be touched to its own numbered quarter of agar. Objects can we lightly and directly touched onto the agar and then removed. Surfaces can be tested by rubbing a sterile cotton swab across one of the agar quarters. Use a new swab for each surface tested.

- Cover of the dish should only be partly raised when samples are being applied to the agar.

- Leave one section unexposed, so this will be your control.

- Then record the type of surface or object exposed to each section of the agar.

- Put your name at the bottom and tape the petri dish shut to prevent contamination.

- Place the dish upside down in an incubator at 37 degrees Celsius and wait 24 to 48 hrs until you remove the petri dish.

Side notes

- The agar looks yellowish

- Label sections on agar side

- Number the quadrants in a small font, so you can see the result later on.

2^nd LAB

- You need prepared nutrient agar sterile Petri dishes, sterile cotton swabs, tweezers, antibiotic disks- 3 different kinds, wax marking pencil, broth culture of bacteria (Bacillus subtilis), sterile paper disk and an incubator.

- Get a sterile Petri dish w/nutrient agar and label the top w/your intials.

- Use a cotton swab dipped in the bacteria broth to cover the entire surface of agar in the Petri dish. (use a back and forth motion to guarantee the entire surface was covered w/ the broth culture

- Divide the dish into four quarters w/ a wax pencil and label them 1-4.

- Add a sterile plain paper disk in the remaining quarter to serve as a control.

- Incubate the dish for 24-48 hrs. at 37 degrees Celsius. If the antibiotics are affective against the bacteria, there will be a clear zone around the disk.

Class Notes

Prokaryotes:

- Evolved and lived all alone on Earth for 2 billion yrs.

- Found where ever there is life and outnumber all eukaryotes combined

- Inhabit soil, skin, and human mouths or habitats that are too cold, too hot, too salty, to acidic, or too alkaline for any eukaryote.

Ex,) black plague, tuberculosis, food poisoning all caused by bacteria

- MOST bacteria are beneficial or benign

6 Kingdom Classification Scheme:

Kingoms

1. Archea
2. Bacteria
3. Protist
4. Plantae
5. Fungi Soil Bacteria
6. Animalia

Prokaryotes lack membrane-enclosed nucleus and numerous other membrane-enclosed organelles.

Two main Branches of Prokaryotes:

1. Archaea (ancient)

- Originate from Earth’s earliest cells

- Most inhabit extreme enviroments Ex.) Thermophiles- heat lovers, Methanogens- give off methane gas and aid in digestion

2. Bacteria

- Causes human diseases

Typical Bacteria Cell

- Absense of nucleus

- Most have cell walls exterior to plasma membrance

- Absense of membrane-enclosed organelles

- About 50% are motile

Shapes of Bacteria: helps to identify prokaryotes

Cocci – spheres Greek for “berries” (sing. Coccus)

Bacilli- rod-shaped (sing. Bacillus)

Spirochete – spiral-shaped (sometimes called spirillum)

Bacterial Reproduction

- Can reproduce at a phenomenal rate if conditions are favorable

- The cells divide by a process called binary fission (copying DNA and then dividing)

- In 24 hrs on cell could create a colony equivalent in mass to 15000 humans.

Bacterial Nourishment: obtaining energy and carbon

Prokaryotic evolution “invented” every type of nutrition we observe in all living organisms, plus some modes unique to prokaryotes.

See you tomorroww! ~ Nazia

Next Scribe: *****HELEN*****

Scribe Post 10/12/11

What we did in class today...

-New seats

-if absent see Mrs Andrews for new seating assignment

-Discussed Test

-Check grade on Homelogic

-Make time during period four or five to look over test to see errors. This will help for

the next test. (Recommended)

-Grade curve!! Tests now out of 52 instead of 59.

Unit 3 Intro

"What Makes you Sick?"

-Intro to disease project

~Found on pages 7-9 in UP

~3 minute commercial about your group's chosen disease.

~In format of DVD, CD, VCR, or other approved method.

-Mention of Spice Lab

~Created between you and your group members.

~Topic must be approved by Mrs. Andrews.

Project Groups

-4-6 people per group

-Will be working on...

-Spice lab

-Disease project

- Class time will be provided for group to work on either project!

Disease Transmission Lab

Found on 9-11 in UP.

-Procedure (modified)

-Choose green cup with clear liquid inside

-Write down cup number in blank space by the Round lines on page 10

-Mix liquid with three other cups, write cup numbers on Round lines.

-Once finished return to the front of the classroom.

~Mrs. Andrews will drop Phenol red indicator

into your cup.

~if pink, positive. If yellow or opaque, negative.

-Fill in table on bottom of page 10

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~Bell rang at the end of this so if you didn't catch it all....

Infected person: Contact 1:Contact 2:Contact 3.

281012

1332616

16101317

12932

201133

821710

3131220

177816

12097

I don't know what happened I'm sorry!

UNIT 3 TEST DATE: 10/28/11

HOMEWORK:

Think

about who you want in your group

Do

pages 9-11

Work

on notes

*Sneak

Peek of tomorrow night's HW: read 189-195 in textbook

p.s: you can feed the fish!!!

NEXT

SCRIBE: Christina****