LAB 3 BIO 39 S24

microscopy in staining. application of this method in microbiological and clinical studies

Contrast/simple staining practice problems: 9. Describe what you would see if you first used the acidic dye nigrosin (which is black) followed by the basic dye safranin (which is pink) when staining a smear of bacteria? 10. Suppose that you have isolated a new bacterial species which has a positively charged cell surface. What type of stain would you use if you wanted to stain the bacterial cells? Explain your answer.

INSTRUCTION: EXPLAIN THOROUGHLY THE TWO THEORIES INVOLVED IN GRAM STAINING (CELL WALL AND LIPIDS THEORIES) IN RELATION TO THE TWO STATEMENTS BELOW. In THEORY OF CELL WALL, Gram-positive bacteria have heavy peptidoglycan, which helps decolorizer (alcohol) to dehydrate the gram-positive cell wall and traps the crystal violet complex inside the cell wall and maintains the purple color of crystal violet.  In THEORY OF LIPIDS, Gram-negative bacteria have high lipid amount (10-15%) in the cell wall, which makes decolorizer (alcohol) easily to remove the crystal violet complex, and then colorless cell wall is stained with safranin and appears pink/red color.

Complete for Additional Differential Staining B: Negative staining ~ thin smear C: Endospore Stain

INSTRUCTION: Answer the question properly Do not copy in Google, plagiarize checker will be used. QUESTION: In the preparation of Bacterial smear and Gram Staining, what is the purpose of: a) heat-fixing the smear b) prolonged application of heat (without breaking slide) on the smear?

Sample Station 7 A. If a student performs a Gram stain on a Gram negative bacterium and stops the stain technique after the iodine step and rinse, what color would you predict the cells to be if you looked at it right now under the microscope?

Solution!

Bacterial Growth lab using E. coli broth culture solution: Each 20-minute interval, absorbance of culture was recorded. When the curve showed plateaus was the absorbance for each culture proportional to the number of bacteria present in the tubes?

method used in lab? we will be using the filter disk method. Which is NOT true of the filter disc A zone of inhibition is an area of no growth around the filter disc. You will apply an agent, such as a particular mouthwash, to the filter disc. You should apply the mouthwash to a plate that has been already been swabbed by the bacteria by pipetting one drop of the mouthwash or rinse directly onto the plate. A zone of inhibition indicates that an agent that has been applied to the filter disc either inhibited or killed the organism on the spread plate.

Cellular stains are commonly used in bacteriology. Which of the following is NOT a reason to stain a bacterial preparation. Cellular stains are commonly used in bacteriology. Which of the following is NOT a reason to stain a bacterial preparation. Determine metabolic properties of a cell. To determine the shape of the bacteria in the culture. To determine what type of cell wall the bacteria has (e.g. gram positive or Gram negative) Identify specific features of a cell (spores, flagella etc)

microbial sensivity lab: Why does the Kirby-Bauer procedure require that the concentration of the bacteria be the same, the stage of growth constant, the growth medium the same, and the concentration or amount of drug in each disk constant?

True or false?       light microscopy has a limit of resolution of 200nm.   phase contrast microscopy can be used to observ thick (more than 2 cells)speciments.     mammalian cells are grown in a humidified incubator at 30C and 5% CO2.

Illustrated Diagram: Make an illustrated diagram of a stepwise procedure for the performance of simple staining and gram staining.   1. Simple Staining

I need help with a microbiology question comparison of the 3 types of microscopy including which shows more detail, which is clearer, and explain which would be preferred when observing paramecium. The three types of microscopy that were used to view paramecium were brightfield,darkfield, and phase-contrast microscopes. Thank you!

True or false ?   images will appear brighter when light waves are in phase.     the condenser portion of the microacope focuses light on the speciment.

Please complete this correctly thank you

Please help using the image i attached below. There are 3 parts to this question. Describe how this is related to light scattering. Note the field is always dark in this type of microscope (and hence, called dark-field). Why is this? Explain how this type of microscope can be used to detect (but not resolve) flagella.

Situational task. Give a detailed description of the colonies (size, shape, nature of the contour of the edge, relief, surface, color, structure). 1 3 5 2 4 6

(please answer all)

Name: Chemotaxis Lab Worksheet 1. What is a model organism and why is it important to scientific studies? List two common model organisms, one for prokaryotic studies and one for eukaryotic studies.

Worksheet Table 1. Special Staining Methods Staining Technique Stain Cellular structure/ Bacteria Example : Albert Malachite green and Metachromatic granules toluidine blue Dorner Dyar Feulgen Fontana-Tribondeau Gray Leifson Levaditi's Neisser Nigrosin Schaeffer-Fulton

Microbiology

Smear Preparation and Staining Lab Smear Preparation 1. What are two goals of a good smear? 2. Why does a bacterial smear need to completely air dry prior to heat fixing? 3. What is the purpose of heat fix step? Simple Stain 1. What is the difference between simple stain and complex stain? 2. Describe the color of an S. aureus after performing simple stain with Safranin Red. Why? 3. What do you conclude after performing simple stain and observing "Purple cells longer than they are wide Gram Stain 1. How does the bacterial cell structure contribute to the mechanism of Gram staining? 2. What is the mordant in Gram stain and why you need it? 3. Why must young cultures be used when doing a Gram stain? Negative Stain 1. а. Name the bacterium used in negative stain b. Describe morphology С. Name the disease caused by this bacterium 2. Describe what you observe under microscope in negative staining.

Illustrated Diagram: Make an illustrated diagram of a stepwise procedure for the performance of simple staining and gram staining.   2. Gram Staining

Please discuss why staining is important in visualizing microbes under the microscope. What different types of staining methods can be used?

Explain briefly why the 100X objective lens of the light microscope is immersed in oil.

List and describe 3 factors that affect the resolution of a compound microscope What reasons could there be for failing to obtain isolated/single colonies on a streak plate? Your answer should be specific to this technique (so should NOT refer to general aseptic technique or good laboratory practice). Give TWOreasons

Phase contrast microscopy - Human Cheek Cells a. b. What is the basic principle of image formation using this microscopy technique? What can be observed and concluded from the image of the specimen?

INSTRUCTION: Answer the question properly Do not copy in Google, plagiarize checker will be used. QUESTION: Discuss the various theories on the Gram stain.

How to properly handle a Microscope? Explain. Thank you.

Topic: yeast cells what is the purpose of cover slip in Dalmau plate? please elaborate

Hello, good day. I am having a problem answering this question and I need your help. Hoping for a response and thank you so much. Question: What are the general rules in grams staining classification of bacteria?