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Bellwork: 09/16/2013

Bellwork: 09/16/2013. Pick up your lab notebook & check it for grading errors. Please point out any mistake I may have made. In the future I will do my best to be more clear on what is expected in your Background & Conclusion Sections.

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Bellwork: 09/16/2013

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  1. Bellwork: 09/16/2013 • Pick up your lab notebook & check it for grading errors. Please point out any mistake I may have made. • In the future I will do my best to be more clear on what is expected in your Background & Conclusion Sections. • Most Missed: An incomplete purpose, problem, and safety section. • An ideal purpose/problem/safety section for our most recent lab: • In this experiment we will be testing a variety of curdling agents combined with whole milk, and we will collect the results as both time and mass/volume. We are doing this experiment to determine which of the tested agents produce the larges amount of cheese/curd within a given amount of time. Safety gloves and goggles should be worn during this experiment since we will be using chemicals that pose a spill hazard and glass that pose a break/shatter hazard.

  2. Lab Sadness: Gloves disposed of outside the lab!

  3. Lab Sadness: Equipment left dirty

  4. Lab Sadness: Agar poured into the cover of a dish

  5. Lab Sadness: Food/drink in the lab

  6. Lab Sadness: Contamination!

  7. Lab Sadness: Contamination!

  8. Lab Sadness: Contamination!

  9. Today: • Check your samples for contamination. • What could have caused this? • If you do have contamination within your plates/tubes/broth, you must clean them out the in chemistry lab and leave them on the Biotech cart in there. • You will prepare your media until you get clean media. • You will complete your microscope investigation: Make sure to include what objective your used to see each slide & why you think this is the best magnification. You should use three of the four objectives with each slide to determine the above • You will perform a simple microscopic measurement exercise, which is detailed on the following slide:

  10. Today: 09/19/2013 • Check your media for contamination. • If you do have contamination within your plates/tubes/broth, you must clean them out the in chemistry lab and leave them on the Biotech cart in there. • By the end of class you should have: • 8 clean agar plates • 4 clean slant tubes • 1 clean broth • Completed the basic microscope sketches • Completed the Microscopic Measurements Activity

  11. Microscopic Measurements: • Using the prepared silk fiber slides: • Pick a slide and record the letter that identifies this slide. • Using the light microscope, describe the order in which the fibers are placed (top to bottom) • Repeat the above steps with three other slides. • If you are having trouble, talk with a lab mate & then ask Mr. Young for help. • Using a piece of 1mmx 1mm grid paper: • Count and record the square or dots of the printed lines of the lower three objectives. • Determine the length & width of: • A cell within the tip of an onion (prepared slide) • A follicle of your own hair • A cyclops (prepared slide)

  12. For Homework: • Write the background & purpose/problem/safety sections in your lab notebook for Lab 2a, “Dissecting a cell and examining its components,” page 14. • From reading your background section it should be clear that you have an understanding of the following: • Cells & cell membranes • The relative sizes of cells • The effect CO2 has on a solution’s pH • The names and uses of the chemicals to be used in this lab

  13. Today: 09/20/2013 • You should get done with “Part I: Separating Cell Structures.” • If you would like me to check your “Purpose/problem/safety” section, I will do that this period. • Modification to the manual instructions: • Steps one through four have been done for you, but you can observe the results of each in the shaker/incubator. • Instead of a slotted spoon you will use wire mess • You also need to save the egg membrane in a small beaker • All beakers/slant tubes/agar plates need to be labeled and covered in parafilm for storage over the weekend.

  14. Today: 09/23/2013 • Turn in your microscope assignment from last week. Please let me know if you have not finished this assignment. • If your parents are attending open house, please tell them to meet in this room for 2nd period, not my downstairs classroom. • You will be tasked with making solutions (soln) for the class today. How would you make a 2% glucose soln? • When you arrive at a step that requires a prepared soln, put your name & the soln you are making on the lab white board. No more than 50 mL of each should be required. Make sure your soln is labeled with what it is, when it was made (09/23/2013) and the initials of those who made it. • You should complete Part II (p. 15/16) today & have a hypothesis for Part III ready for tomorrow.

  15. Today: 09/24/2013 – 09/26/2013 • You will complete Part II: Testing Standard Solutions & move onto Part III: Molecular Composition of Egg Components. • Before moving onto Part III, make sure you know what a positive & a negative result for each indicator looks like. Make sure this is written down in your lab notebook! • Make sure you have your hypothesis written prior to starting Part III. I will review your hypothesis for this lab if you would like. • Once you have completed Part III, please take your glassware & other equipment to room 2118, clean it, then return it. • Make sure your calculations for your solutions throughout this lab can be found in your Data section of this lab. • On a loose piece of paper, answer questions 2, 4, and 5 on page 17 of your lab manual under the “Thinking like a Biotechnician” section. This will be taken for a separate daily grade for this lab exercise.

  16. Today: 09/27/2013 • Clean up any of your lab materials. I will deduct 10 points from your lab notebook grade if I have to clean up after you/your lab group. • The rest of your class time is dedicated to finishing the lab entry for Parts I/II/III of this week’s lab. • Once you have completed your data analysis section & conclusion, please turn your lab notebook in for grading. • Additionally, or for homework: On a loose piece of paper, answer questions 2, 4, and 5 on page 17 of your lab manual under the “Thinking like a Biotechnician” section. This will be taken for a separate daily grade for this lab exercise.

  17. Bellwork: 09/30/2013 • What are the three shapes of bacterial cells? • In science, what is a “model” organism? Why would these organisms be used?

  18. Today: 09/30/2013 • We will begin work on “The Characteristics of Model Organisms” lab (page 17). • Prior to writing your background and purpose/problem/safety sections you will inoculate your prepared broth with E.coli and streak a plate with yeast culture. • E.coli inoculation: • Using a sterile inoculation loop, scrape off a small colony from the prepared slant tube. • Make sure to open and close the prepared slant tube quickly. • Transfer the colony to your sterile broth. • Label the broth with: Your Name, Date of Inoculation, and what cells your are growing in the broth. • Place the inoculation loop circle down in isopropyl alcohol. • Place your broth in the 37°C shaker incubator.

  19. Today: 09/30/2013

  20. Today: 10/01/2013 • Before entering the lab, you must get your background, purpose/problem/safety, and hypothesis sections initialed by Mr. Young. Please be mindful that I am only checking that it is complete, not that it is correct. • Check your yeast cultures for growth, make not of the appearance of the colonies & allow them to grow for another 24 hours. • You will transfer aspergillus colonies from the prepared plates to your slant tubes as demonstrated by Mr. Young. • Streak your other 4 plates with your E.coli culture if you have successfully grown E.coli in your broth.

  21. Today: 10/02/2013 • Before entering the lab, you must get your background, purpose/problem/safety, and hypothesis sections initialed by Mr. Young. Please be mindful that I am only checking that it is complete, not that it is correct. • Check your yeast cultures for growth, record the growth as “no growth,” “slight growth,” or “growth” on the white board in the lab. Additionally, record which temperature had the greatest amount of growth • You will transfer aspergillus colonies from the prepared plates to your slant tubes as demonstrated by Mr. Young. • Streak your other 4 plates with your E.coli culture if you have successfully grown E.coli in your broth. • If your broth is still clean, pipette over 1 mL (1000 µL) from a successful stock & incubate for another 24 hours. • Streak your plates using the successful stock.

  22. Today: 10/03/2013 • Before entering the lab, you must get your background, purpose/problem/safety, and hypothesis sections initialed by Mr. Young. Please be mindful that I am only checking that it is complete, not that it is correct. • Check for growth in all of your remaining samples & write your results on the board in the lab. • If you have successfully grown E.coli on a plate, please label it with your name, date, and “E.coli” and place it in the fridge for next week. • You should dispose of all other plates and tubes unless instructed to do otherwise. • To remove agar from the slant tubes, place the tube inverted in a beak and put the beaker in the microwave until the agar melts out. BEWARE OF HOT GLASS!

  23. Today: 10/04/2013 • Clean all of your equipment. Unless you were instructed otherwise, all you should have after this week is an E.coli broth culture and an E.coli agar plate. • Check the fridge, incubators, etc. for any other media that needs to be cleaned/disposed of. • You will lose 10 points off this lab if I have to clean it up over the weekend. • The rest of the time will be for you to finish your data analysis/conclusion section(s). Make sure you record your classmates’ data.

  24. Expectations for Conclusions: • Make sure you discuss your group’s results in comparison to the class’s results. • Discuss some possible reasons for variation in results between you and your classmates. • Make sure to describe each result (variable temperatures) for each of your model organisms. • Describe what your hypothesis was & how your results did or did not match your hypothesis. • Practical Applications: Make sure to include why model organisms are important for science. Also include how the details you learned about the growth rates associated with variable temperatures would be connected with an average day in the life of a scientist using these organisms (growing them quickly, slowly, etc.). • For a daily grade: Answer all 4 “Thinking like a Biotechnician” Questions on page 21. • Additionally, please tell me what you like about this class so far, and what changes I need to make. You may turn this in anonymously if you prefer.

  25. Today: 10/07/2013 • Take the first 10 minutes of class and read the Background information on page 29 of our lab manual. • Do NOT write a background, problem statement, etc. This will not be a full lab.

  26. Gram Staining Steps • Place a small drop of distilled water in the middle of your slide. • Flame your inoculation loop, allow it to cool, remove a small amount of E. coli from your plate, and add it to your drop of water. • Flame your loop and allow it to cool. Spread the water/E. coli drop thinly over the central 1/3rd of the slide and allow it to air dry. • Heat-fix the cells to the slide.

  27. Gram Staining Steps • Cover your cell sample with Crystal Violet for one minute. • Thoroughly rinse both sides of the slide in the sink. • Stain your sample with iodine solution for one minute, then rinse with water. • Decolorize the cells by pooling ethyl alcohol on one side of the slide, then tilt the slide to allow the alcohol to run across the cells and off the other side of the slide. Repeat until no more color (purple) is running off the slide. Immediately rinse with water. • Stain with safranin for one minute. • Carefully and quickly rinse off the excess safranin. • Observe under oil immersion.

  28. Background Expectations Gram Staining lab: The following should be evident, but not simply listed, in your background entry. • How and when was the technique of gram staining developed? • Gram staining is the most widely used staining procedure in bacteriology. Why is it so common? What is it used for? • What is the difference between gram(+) and gram(-) cells? How can this be distinguished visually? • What are the solutions being used & what safety precautions should be taken when using them? • Your background must be initialed (checked that it is complete, not necessarily correct) by Mr. Young before you start on the lab investigation.

  29. Today: 10/10/2013 Gram Stain the Following Organisms: • Bacillus cereus • Micrococcus luteus • Clavibactermichiganesis • Branhamellacatarrhalis • Serratiamarrescens • Label each as gram (+) or gram (-), as well as name the shape of the bacteria (coccus, bacillus, spirillum) • You must show me your stain at 400x & get my signature approval for each stain. • Do not use oil immersion

  30. Bellwork: 10/15/2013 • What occurs during each of the following steps of gram staining: • Crystal Violet Stain • Iodine Stain • Ethyl Alcohol Wash • Safranin Stain • What would each of the following stains be used for: • Gram Staining • Methylene Blue Staining (Biology) • Acid-Fast Staining

  31. Bellwork: 10/15/2013 • What occurs during each of the following steps of gram staining: • Crystal Violet Stain – penetrates the cell walls of both gram(+) and gram (-) cells and binds with negatively charged parts of the bacterial cell • Iodine Stain – binds with CV, creating a large complex that will become trapped within the cell • Ethyl Alcohol Wash – interacts with the lipids in the cell membrane, causing gram(-) cells to lose its outer lipopolysaccharide layer, allowing the CV-I complex to be washed away • Safranin Stain – a + charged counter stain that will give the now colorless gram(-) cells a pink or red color

  32. Bellwork: 10/15/2013 • What would each of the following stains be used for: • Gram Staining – detects the presence/absence of a thick layer of peptidoglycan in a bacterial wall • Methylene Blue Staining (Biology) – a general stain to isolate DNA/RNA within a cell • Acid-Fast Staining – a technique that causes a dye to bind to cells with a high concentration of mycolic acid • Used in the identification of tuberculosis, bacterial spores, oocysts of parasites, eggs & cysts of other parasites (tape worms)

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