Neutralization of Acids and Bases
Neutralization of Acids and Bases. v
Neutralization of Acids and Bases
Neutralization of Acids and Bases. v
Neutralization of Acids and Bases
2420-Lab 3- Bacterial Staining Techniques-II-(Differential).
Answer following questions after reading the information and watching the video from the link below. Use color RED or BLUE for your answers. Submit the completed document on eCampus for grading. Refer to divulge
· the textbook chapter 3 (3.2) (Nester- McGraw Hill)
· Link: Bacterial Staining Techniques-II, Virtual Edge Experiment-4
1. What is differential staining?
Differential staining is the process of staining that involves the use of a single stain. This allows for efficient differentiation of structures/cellular components, and microorganisms of a single organism.
Watch the video of Gram Staining from the textbook chapter 3- review 3.2 (pages 53-54), 3.5 (pages 65-67– cell wall of prokaryotic cells) and answer the following questions.
2. What is the purpose of Gram staining?
Gram staining allows for the determination of chemical composition of bacterium cell walls.
3. Who invented the Gram staining procedure?
Hans Christian Gram
4. What is the first stain used in Gram staining procedure?
The basic dye crystal violet (primary stain)
5. Do all cells pick up this stain?
Bacteria cell walls pick up the primary stain (crystal violet).
6. What is the function of a mordant?
A mordant chemically alters the shape of the dye molecule. This allows for the intensification of the stains in the cells/tissue preparations.
7. Which mordant is used in the Gram staining procedure?
Iodine
8. What would be the result if the mordant is forgotten from the procedure?
The crystal violet molecules will not form a complex the reaction will be red.
9. What is alcohol used for?
The alcohol is a lipid solvent used to dissolve the gram’s-negative cell wall outer membrane. Alcohol acts as the decolorizing agent.
10. Why is decolorization necessary?
Allows for the differentiation of the gram-positive bacteria from the gram-negative bacteria
11. What is a counterstain?
This is a stain with contrasting color to the principal stain. This increases visibility under the microscope.
12. Which counterstain is used in Gram staining?
Safranin
13. What are cells called that retain the primary stain?
Gram positive
14. What are cells called that lose the primary stain?
Gram negative
15. What are cells called that take up the counterstain?
Gram positive and gram negative
16. What type of cells do not take up the counterstain?
Gram positive
17. After the Gram staining procedure, Gram positive bacterial cells appear ___purple_______ colored.
18. After the Gram staining procedure, Gram negative bacterial cells appear _____red_______ colored.
19. Which component of the cell wall in Gram positive bacteria is responsible for the retention of the primary stain?
Peptidoglycan
20. Which component of the cell wall in Gram negative bacteria is responsible for the retention of the counterstain?
Peptidoglycan
21. What would be the color of Gram negative bacterial cells if the decolorization step is forgotten? Explain.
The color would remain purple. This will be regarded as a false positive result.
22. Which bacteria were used in this experiment and what were their shapes? (From the textbook, review 3.3- Morphology of prokaryotic cells)
Spherical in shape. The cells used were prokaryotic cells.
23. From what you have learned from the textbook, if a patient has E. coli infection which are Gram negative bacteria, would you advise them to take a course of Penicillin? Why or Why not?- Explain
No, it is not advisable for the patient to take penicillin. This is because E. coli is resistant to beta lactams like penicillin and other non-beta lactams.
24. Following picture shows the Gram staining result. Point out (or describe) Gram positive and Gram negative cells from the picture. Be sure to specify morphology:
The gram positive cells are the violet/purple looking cells under the microscope. The gram positive cells appear purple because the bacteria will retain the primary stain i.e. crystal violet. The gram negative bacteria will appear pink under the microscope.
Read the text from the following to help answering the following questions.
· link Acid-fast Staining,
· textbook chapter 3- section 3.2
25. List two genera of bacteria that are stained for identification by using Acid-fast staining method.
Nocardia species, mycobacterium avium-intracellulare complex
26. Which fatty acid is found in the cell walls of acid-fast bacteria?
Mycolic acids
27. Which primary stain is used in the acid-fast staining procedure?
carbol fuchsin
28. Why is steaming necessary at this step?
Steaming loosens up the waxy layer hence promoting entrance of the primary stain in the cell.
29. Which counterstain is used in the acid-fast staining procedure?
Methylene blue
30. Why is acid-alcohol used to decolorize in the acid-fast staining process instead of regular ethanol?
Acid-alcohol acts as the decolorizing agent because the acid-fast cells are resistant to decolorization because the primary statin is soluble in the cellular waxes as compared to the decolorizing agent.
31. Which two types of bacteria were used in this experiment?
Nocardia species, mycobacterium avium-intracellulare complex
32. Which of the above two types of bacteria were acid-fast? (or retained the primary stain?)
Mycobacterium retains the primary pink stain.
33. From the picture below, point out the acid-fast cells:
The red cells in the image s
34. If you are working in a clinical diagnostic laboratory, which of the above staining methods would you use to predict the cause of infection under following conditions?
a. Tuberculosis
Sputum smear microscopy
b. Strep throat
Gram staining
2420-Lab 3- Bacterial Staining Techniques-II-(Differential)
Lab: RNA. Lab: RNA
In this lab, you will learn about the types of RNA molecules and you will study the details of transcription and translation.
Objectives:
Learn about the types of RNA molecules produced by cells.
Study the details of transcription and translation.
Time Requirements:
This lab should take two hours to complete.
RNA Lab Report
If a codon is mutated, say from GGU to CGU, is the same amino acid specified? _______
Using information from the course and online research, answer the questions.
Searching Websites:
Conduct a keyword search to find websites. To begin a keyword search, start by searching broad terms such as RNA, transcription, translation, or the scientist’s name. The resulting list of websites can give you a lot of information, but how do you know if it is reliable? Some basic guidelines can help you when you open a website and try to determine its reliability.
Always consider a site’s:
· Objectivity – Excessive expressions of emotion, opinions, and stereotyping are tip-offs that the information on a site may be biased.
· Ownership and contributors – Go to the Home or About page of the website and find out who sponsors and writes for the site. Look for contributors who have reliable credentials, such as “Harvey Jones, Professor, University of Wisconsin—Madison.”
· Writing style and mechanics – Check the grammar, spelling, and writing style on the site. Errors and awkwardness are signs of a nonprofessional website.
· Currency – Look for publication or copyright dates associated with the site; the more current the better.
· Links – What links does the site contain? A reliable website will offer links to other reliable websites, not to “junk” sites.
Keyword Search: RNA, transcription, translation, or the scientist’s name.
Scientific Analysis:
1. Scientists use observations and inferences for many discoveries and conclusions in genetics. What is the difference between an observation and an inference? Give an example of each.
2. If DNA from a cell is placed in a test tube containing the enzyme DNA polymerase and nucleotides, the result is new copies of the original DNA. This evidence was used to understand DNA replication (DNA passing information from one generation to the next). Write an explanation detailing why this clue represents solid data and is not an opinion or an inference.
3. In your own words, describe Crick’s Central Dogma. Explain why this is an inference.
Scientific Contributions
There were many scientists that contributed to decoding the genetic code. Explore the contributions of some scientists.
4. Describe Marshall Nirenberg’s contribution to determining the role of RNA in genetics.
5. Describe how Seymour Benzer’s phage experiments contributed to deciphering the genetic code.
6. Describe Seymour Brenner’s contribution to cracking the genetic code with respect to translation.
Replication, Transcription, and Translation
Place an x in the box for which process each item is a characteristic.
Characteristic | Replication | Transcription | Translation |
1. RNA polymerase unwinds the DNA double helix. | |||
2. This is the first part of protein synthesis. | |||
3. After the stop codon is reached, the protein is separated from the ribosome. | |||
4. Amino acids sequences are made from RNA sequences. | |||
5. A copy of RNA is made from DNA. | |||
6. Peptide bonds form between amino acids. | |||
7. Uracil hydrogen bonds with adenine. | |||
8. tRNA brings amino acids to the ribosome. | |||
9. Copies of the original DNA are made. | |||
10. Thymine hydrogen bonds with adenine. |
7. Use the table and your research to compare and contrast transcription and translation.
8. In your own words, explain the function of mRNA, tRNA, and rRNA.
9. Use the codon chart to convert this sequence into an amino acid:
UCU-CGA-GCC-GUU-GGG-UGA
10. Explain why an mRNA strand composed of only uracil nucleotides (UUUUUUUUUU) did conclusively prove that the DNA code was a triplet code.
11. How could this mRNA sequence support a triplet code? ACACACACACAC
12. List the steps involved in protein synthesis, beginning with the DNA code in the nucleus and ending with a polypeptide. Try to explain it in 10 steps.
13. A mutation in a codon may not result in a change of an amino acid in the protein sequence. Explain why, using the genetic code chart to give an example.
© KC Distance Learning
Principles of taxonomy. To introduce you to principles of taxonomy as you look at morphological characteristics of sea shells and construct an evolutionary tree.
Directions
Go to the link http://media.hhmi.org/biointeractive/click/shells_online/index.html and work through the lab sorting sea shells based on morphological characteristics to study evolutionary relationships.
Please take notes for your laboratory report. You will add an introduction later. Write a short note describing each step of identifying and selecting snails as you work through the lab. Please take a screen shot of the final drawing showing the evolutionary relationship of all snails listed.
Please answer the following questions:
Why was the scallop among the snails? (HINT: Watch “Dr. Olivera discusses major molluscan groups”)
What additional tests could be used to examine evolutionary relationships among molluscs (snail species)? (HINT: Watch “Dr. Olivera discusses how to classify shells”)
How was the name of different cone snail specied decided? (HINT: Watch the video “Dr. Olivera discusses species names”)
Where are cone snails found and what are their feeding habits? (HINT: Click on snail images on the final evolutionary tree for more information about species).
Describe the evolutionary history of snails (Molluscs). In which eon, era and period did the first snails evolve? (HINT: Textbook, chapter 14.3)
The laboratory report will have a title page (APA format), and an introduction. Summarize the life history of cone snails. List your steps to classify the snails under methods, post the final picture of snail specis under results and discuss limits of morphological classification in the discussion section of the lab report. Suggest additional tests which may clarify cone shell taxonomy. You should also have a reference section, with the textbook and web page listed in APA format.
Save your completed lab report in .rtf, .doc, or .docx format. Name it as “Taxonomy Lab Report_Your Last Name.”
Submit your lab report via the submission link above. Please only submit the completed lab report for grading.
Please review the grading rubric for the assignment for additional details and grade criteria.
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