How can the thickness of the smear affect the staining procedure? If it is too thick it won’t stain properly. The stain will not get to the lower layers and clumps of cells may not be decolorized.
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Contents
- 1 Which Gram staining step is affected by the thick smear?
- 2 What is the disadvantage of having a thick smear when staining?
- 3 What are the factors affecting the result of Gram staining?
- 4 Why is a thin bacterial smear important?
- 5 What happens if your smear is too thick?
- 6 Why is it important to fix the thin smears and not the thick smear?
- 7 Is it important that the smear is thick in order to ensure that the stain will be retained on the slide?
- 8 What is the purpose of thick smear?
- 9 What is the significance of a thick and thin smear for identifying malaria parasite?
- 10 What could affect the quality of a smear?
- 11 What is the advantage of the Gram stain over the simple stain?
- 12 What is the most common mistake when making a smear for a Gram stain?
- 13 How does culture age affect the result of Gram staining?
- 14 What are the factors that will affect the staining affinity of bacteria?
- 15 Which step is the most crucial or most likely to cause poor results in Gram staining?
- 16 Why must the stain be spread very thin in the negative staining procedure?
- 17 What is the purpose of the smear preparation?
- 18 What is the purpose of applying a stain to a bacterial smear?
- 19 Why staining is important in microbiology?
- 20 Why is it important to prepare a thin smear for Gram staining?
- 21 Why is it so important to create a thin smear before doing any staining technique what could happen if the smear is too thick?
- 22 Why are thick or dense smears less likely to provide a good smear preparation for microscopic evaluation?
- 23 What are the advantages of using thick and thin blood smears for malarial studies?
- 24 What is thin and thick smear?
- 25 What 3 things determine the thickness of the smear?
- 26 Why must smears be heat fixed before staining?
- 27 Why does the age of the bacterial culture matter for Gram staining?
- 28 How does the age of a culture affect the Gram stain reaction what is an optimum culture age for a valid gram reaction?
- 29 How does the Gram staining procedure help doctors to treat patients?
- 30 How do you prepare a smear for staining?
- 31 What is negative staining in microbiology?
- 32 What factors can affect the results of a Gram stain and why?
- 33 What are the advantages of stained smear preparation?
- 34 What happens when a bacterial smear is overheated?
- 35 What are two common mistakes when making a bacterial smear for staining?
- 36 Is it important that the smear is thick in order to ensure that the stain will be retained on the slide?
- 37 What are some consequences of leaving a stain on a bacterial smear too long over staining?
- 38 What factors affect staining?
- 39 What could affect the quality of a smear?
- 40 How does culture age affect the result of Gram staining?
- 41 What are two mistakes you could make that would make a Gram stain less reliable?
- 42 Which Gram staining step is most likely to cause misleading result if you have a thin smear?
- 43 What if the smear you prepare becomes too dense?
- 44 Why is the size more accurate in a negative stain than in a simple stain?
- 45 Why is it important to have a thin layer of cells on the smear preparation?
- 46 What is the importance of having a thin layer of bacteria in smear preparation?
- 47 What is the importance of staining bacterial smear?
- 48 What is the importance of staining procedures?
- 49 Why is a thin smear better than a thick smear microbiology?
- 50 What is smear preparation What is the importance?
- 51 Why staining is important in microbiology?
- 52 How does the heaviness of a bacterial smear affect its microscopic analysis?
Which Gram staining step is affected by the thick smear?
The thickness of the smear used in the Gram stain will affect the result of the stain. The step that is most crucial in effecting the outcome of the stain is the decolorizing step.
What is the disadvantage of having a thick smear when staining?
Do NOT make your smear suspensions too thick. The dye will not penetrate well, and there will be far too many bacterial cells to see individual shapes and arrangements.
What are the factors affecting the result of Gram staining?
The many variables that can affect this stain are age of the culture, amount of decolorizer used, the time of decolorization, the type of organism (acid-fast bacteria and spores do not stain well), thickness of the smear, and the general care of the stainer.
Why is a thin bacterial smear important?
Why is it important to make the smear thin? thin smear, because the thickness will determine whether or not you can visualize individual cell morphology(form), their arrangements, or details regarding gram reaction or internal structure.
What happens if your smear is too thick?
Smears that are too thick will be difficult to decolorize and imposable to read. Do not cover the entire slide with the sample. This will make handling difficult and areas may be missed during decolorization. An area the size of a nickel usually is adequate.
Why is it important to fix the thin smears and not the thick smear?
6. Thick smears are mainly used to detect infection and to estimate parasitemia. Thin smears allow the examiner to identify malaria species, quantify parasitemia, and recognize parasite forms like schizonts and gametocytes.
Is it important that the smear is thick in order to ensure that the stain will be retained on the slide?
Water is applied to the slide before emulsifying cells from a solid medium. It is important that the smear is thick in order to ensure that the stain will be retained on the slide.
What is the purpose of thick smear?
A thick blood smear is a drop of blood on a glass slide. Thick blood smears are most useful for detecting the presence of parasites, because they examine a larger sample of blood. (Often there are few parasites in the blood at the time the test is done.)
What is the significance of a thick and thin smear for identifying malaria parasite?
Blood smears are taken most often from a finger prick. Thick and thin blood smears will let doctors know the percentage of red blood cells that are infected (parasite density) and what type of parasites are present.
What could affect the quality of a smear?
Concentration and freshness of reagents may affect the quality of the stain. Washing and drying of the smear between steps should be consistent. Excess water left on the slide will dilute reagents, particularly Gram’s iodine.
What is the advantage of the Gram stain over the simple stain?
What is the advantage of the Gram stain over a simple stain such as methylene blue? Gram staining highlights different bacteria types through the use of special dyes. It aids in the diagnosis of a specific organism and tells the difference between gram negative and gram positive bacteria.
What is the most common mistake when making a smear for a Gram stain?
In this study, we present a review of over 6,000 Gram-stains and establish an error rate of around 3%, with the most common reason for error being an over-decolourisation step resulting in organisms that should be Gram-positive appearing as Gram-negative.
How does culture age affect the result of Gram staining?
Old cultures tend to lose the peptidoglycan cell walls, which predisposes gram-positive cells to be gram-negative or gram variable. Gram stain is not useful for organisms without a cell wall like Mycoplasma species, and for smaller bacteria like Chlamydia and Rickettsia species.
What are the factors that will affect the staining affinity of bacteria?
- Concentration of the dye – The greater the concentration of the dye, the more the dye is bound to tissue components.
- Temperature – An increase in temperature increases the rate at which the dye diffuses throughout the tissue sample.
Which step is the most crucial or most likely to cause poor results in Gram staining?
Excessive Decolorization
It is clear that the decolorization step is the one most likely to cause problems in the Gram stain.
Why must the stain be spread very thin in the negative staining procedure?
Why must the stain be spread very thin in the negative staining procedure? If it is too thick it will never dry. stain all bacterial cell walls. the alcohol removes the lipids of the Gram-negative wall making the wall more porous.
What is the purpose of the smear preparation?
The preparation of a smear is required for many laboratory procedures, including the Gram-stain. The purpose of making a smear is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure.
What is the purpose of applying a stain to a bacterial smear?
What is the purpose of applying a stain to a bacterial smear? To provide contrast between the organism and the background. Since bacterial cells are generally transparent, it is very helpful to stain bacteria to provide contrast.
Why staining is important in microbiology?
The most basic reason that cells are stained is to enhance visualization of the cell or certain cellular components under a microscope. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample.
Why is it important to prepare a thin smear for Gram staining?
The preparation of a smear is required for many laboratory procedures, including the Gram-stain. The purpose of making a smear is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure.
Why is it so important to create a thin smear before doing any staining technique what could happen if the smear is too thick?
If your slide is wet and you heat fix it, the bacteria will boil and the cellular morphology will be lost. If your slide is wet and fix it in methanol, it will most likely wash off the slide. Smears that are too thick will most likely wash off the slide regardless of the fixation method.
Why are thick or dense smears less likely to provide a good smear preparation for microscopic evaluation?
Why are thick or dense smears less likely to provide a good smear preparation for microscopic evaluation? It will diminish the amount of light that can pass through making it difficult to visualize the morphology of single cells under the microscope. Some times the stain can’t penetrate all of the bacteria.
What are the advantages of using thick and thin blood smears for malarial studies?
Thick blood film
More sensitive by 30 times than thin films because: the blood is concentrated allowing a greater volume of blood to be examined and. malaria parasites are concentrated as the RBCs are lysed.
What is thin and thick smear?
Thin and thick smears are two different types of blood smears that contain red blood cells. In a thin smear, a drop of blood is spread across a large area of a slide. In a thick smear, a drop of blood is put on a glass slide.
What 3 things determine the thickness of the smear?
- Angle of the spreader slide ( > angles = > thickness)
- Size of blood drop.
- Speed of spreading.
Why must smears be heat fixed before staining?
Answer and Explanation: Bacterial smears are “heat fixed” on the microscope slide before staining to affix the cells to the slide so that they do not wash off… See full answer below.
Why does the age of the bacterial culture matter for Gram staining?
what is an optimum culture age for a valid gram reaction? old cultures of gram positive cells may not retain stain as well as younger cultures and could give false negative results (ex) pink cells. Cultures that are 16-18 hrs are best.
How does the age of a culture affect the Gram stain reaction what is an optimum culture age for a valid gram reaction?
Old cultures can convert to gram-variable or gram-negative giving erroneous results. What is an optimum culture age for a valid gram reaction? Optimum age is 16-18 hours. Which step in the gram stain procedure is most prone to error?
How does the Gram staining procedure help doctors to treat patients?
The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. This can help your doctor determine an effective treatment plan.
How do you prepare a smear for staining?
What is negative staining in microbiology?
Negative staining employs the use of an acidic stain and, due to repulsion between the negative charges of the stain and the bacterial surface, the dye will not penetrate the cell. In negative staining, the results yield a clear cell with a dark background.
What factors can affect the results of a Gram stain and why?
The many variables that can affect this stain are age of the culture, amount of decolorizer used, the time of decolorization, the type of organism (acid-fast bacteria and spores do not stain well), thickness of the smear, and the general care of the stainer.
What are the advantages of stained smear preparation?
- Better Visualization. Bacterial organisms are so small that most of them are visible only under a microscope with a magnification power of 1000X. …
- Identification and Classification. …
- Detection of Viability. …
- Identification of Cellular Structures.
What happens when a bacterial smear is overheated?
Excessive heat kills the bacteria and therefore interferes with stain penetration. Overheating the glass slide may create microfissures in the glass that will retain stain and produce inconclusive results.
What are two common mistakes when making a bacterial smear for staining?
- Applying too much bacteria to the slide.
- Not heat fixing the bacteria before staining.
- Wiping off the slides will result in a loss of bacteria present.
Is it important that the smear is thick in order to ensure that the stain will be retained on the slide?
Water is applied to the slide before emulsifying cells from a solid medium. It is important that the smear is thick in order to ensure that the stain will be retained on the slide.
What are some consequences of leaving a stain on a bacterial smear too long over staining?
. What are some consequences of leaving a stain on a bacterial smear too long (over-staining)? Consequences of over-staining are that the cell wall may be broken up or completely destroyed which would result in a loss of morphological characteristics of the bacterial cell.
What factors affect staining?
Factors that affect staining include: Concentration of the Dye – The greater the concentration of the dye, the more the dye is bound to tissue components. Temperature – An increase in temperature increases the rate at which the dye diffuses throughout the tissue sample.
What could affect the quality of a smear?
Concentration and freshness of reagents may affect the quality of the stain. Washing and drying of the smear between steps should be consistent. Excess water left on the slide will dilute reagents, particularly Gram’s iodine.
How does culture age affect the result of Gram staining?
Old cultures tend to lose the peptidoglycan cell walls, which predisposes gram-positive cells to be gram-negative or gram variable. Gram stain is not useful for organisms without a cell wall like Mycoplasma species, and for smaller bacteria like Chlamydia and Rickettsia species.
What are two mistakes you could make that would make a Gram stain less reliable?
Choose two mistakes that you could make that would make a Gram stain less reliable. Putting too much dye and leaving it on too long. What is correct about Simple stain? Always done with basic dye.
Which Gram staining step is most likely to cause misleading result if you have a thin smear?
The decolorization of the cells is the most “operator-dependent” step of the process and the one that is most likely to be performed incorrectly. Rinse with water to stop decolorization. Rinse the slide with a counterstain (safranin or carbol fuchsin) which stains all cells red.
What if the smear you prepare becomes too dense?
2. What if the smear you prepare becomes too dense? When the smear becomes too dense it becomes harder for light to pass through which makes it har to see the shape and size of the organism.
Why is the size more accurate in a negative stain than in a simple stain?
Why is the size more accurate in a negative stain than in a simple stain? Because it’s not subjected to heat fixing or other harsh chemicals– ensuring that cell-size does not change or be distorted by the stain. Air-drying helps keep the size as well.
Why is it important to have a thin layer of cells on the smear preparation?
The thin-layer method reduced screening time but improved quality, because cytotechnologists devoted more time per unit area. The increase in time required for preparation offset the decrease in screening time, making the total testing time for a thin-layer slide comparable with that of a conventional smear.
What is the importance of having a thin layer of bacteria in smear preparation?
A bacterial smear is a thin layer of bacteria placed on a slide for staining. Preparing the smear requires attention to a number of details that help prevent contamination of the culture and ensure safety to the preparer.
What is the importance of staining bacterial smear?
Most bacteria are colorless, so they generate little contrast in the microscope field. Therefore, to see bacteria under the microscope, it is necessary to apply color using a staining reagent. Once stained, bacteria can be observed and studied in terms of their shape, size and arrangement.
What is the importance of staining procedures?
The purpose of staining is to increase the contrast between the organisms and the background so that they are more readily seen in the light microscope.
Why is a thin smear better than a thick smear microbiology?
1. Thick blood smears are most useful for detecting the presence of parasites. Thin blood smears helps to discover which species of parasite is causing the infection.
What is smear preparation What is the importance?
The preparation of a smear is required for many laboratory procedures, including the Gram-stain. The purpose of making a smear is to fix the bacteria onto the slide and to prevent the sample from being lost during a staining procedure. A smear can be prepared from a solid or broth medium.
Why staining is important in microbiology?
The most basic reason that cells are stained is to enhance visualization of the cell or certain cellular components under a microscope. Cells may also be stained to highlight metabolic processes or to differentiate between live and dead cells in a sample.
How does the heaviness of a bacterial smear affect its microscopic analysis?
Why are thick or dense smears less likely to provide a good smear preparation for microscopic evaluation? It will diminish the amount of light that can pass through making it difficult to visualize the morphology of single cells under the microscope. Some times the stain can’t penetrate all of the bacteria.
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