Prescott's Microbiology
Prescott's Microbiology
10th Edition
ISBN: 9781259281594
Author: Joanne Willey, Linda Sherwood Adjunt Professor Lecturer, Christopher J. Woolverton Professor
Publisher: McGraw-Hill Education
bartleby

Videos

Textbook Question
100%
Book Icon
Chapter 2, Problem 1CHI

Compare, Hypothesize, Invent

1. If you prepared a sample of a specimen for light microscopy, stained it with the Gram stain, and failed to see anything when you looked through your light microscope, list the things that you may have done incorrectly.

Expert Solution & Answer
Check Mark
Summary Introduction

Danish physician, Christian Gram in 1884, developed a gram staining procedure. In bacteriology, this method is employed widely. This technique will be carried out in clinical laboratories during the diagnosis of infectious disease. This staining method is an example of the differential staining technique. Using this technique, most of the bacteria are classified into two groups.

Explanation of Solution

In Gram staining, sample (bacterial cells) will be stained with crystal violet. They all will appear in purple colour. Next step is the addition of mordant-iodine, and then the stain will be fixed in the sample due to the formation of crystal violet (CV) and iodine complex. The third step is de-staining with water plus alcohol. If the stain remains then the bacteria are Gram-positive (purple) and if colour come out, they are Gram-negative group. These will appear in red colour.

Students who are performing the Gram-staining procedure should carry out all the steps carefully. This because an error in each might result in false positive result or many issues. Some of the issues that might happen when the procedure is performed well are given below:

Insufficient heat fixation: Sufficient heat is required so that the sample will be fixed over the slide.

Over-vigorous washing: If the sample is washed vigorously, the cells might be removed from the slide

Improper staining or destaining: De-staining procedure or staining must be carried out for required time otherwise the bacterial cells will not take the stain.

Over decolourization and focussing: Over decolourization will result in the removal of CV+ iodine complex, making the Gram-negative positive cells appear like Gram-negative cells. This will affect the result.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
Match each microscope component with its description or function. 1. Objective 2. Ocular 3. Condenser 4. Diaphragm a. gathers light rays and focuses on object b. eyepiece c. magnifying element located on nosepiece d. disk with an opening that adjusts amount of light that contacts specimen
7. Use the image to answer the following questions: (2) A student collects some of this bacteria to create a slide then performs a Gram stain as shown here: A. How many different types of bacteria are growing on the petri dish? B. How do you know (how can you tell the difference between the types of bacteria)? C. What is the Gram reaction and morphology of these cells? D. Based on the Gram stain, could this colony be used to grow pure culture? How do you know?
7. Give an example of a differential stain. 8. What is a medium? 9. What is the definition of a bacterial colony? 10. Why do we want to get an isolated bacterial colony from a mixed culture?
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Human Anatomy & Physiology (11th Edition)
Biology
ISBN:9780134580999
Author:Elaine N. Marieb, Katja N. Hoehn
Publisher:PEARSON
Text book image
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Text book image
Anatomy & Physiology
Biology
ISBN:9781259398629
Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa Stouter
Publisher:Mcgraw Hill Education,
Text book image
Molecular Biology of the Cell (Sixth Edition)
Biology
ISBN:9780815344322
Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter Walter
Publisher:W. W. Norton & Company
Text book image
Laboratory Manual For Human Anatomy & Physiology
Biology
ISBN:9781260159363
Author:Martin, Terry R., Prentice-craver, Cynthia
Publisher:McGraw-Hill Publishing Co.
Text book image
Inquiry Into Life (16th Edition)
Biology
ISBN:9781260231700
Author:Sylvia S. Mader, Michael Windelspecht
Publisher:McGraw Hill Education
Bacterial Infections in Humans; Author: Professor Dave Explains;https://www.youtube.com/watch?v=FeFKAl9KyMg;License: Standard Youtube License