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Neither. Alloreactivity has to do with a lymphocytes reacting to a foreign antigen. Positive and negative selection are processes of central tolerance which is to say that they deal with a T cell's ability to bind self-antigen.

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Which step is most crucial or most likely to cause poor results in the gram stain?

Gram staining is a type of differential staining in which two types of bacteria are differentiated on the basis of their cell wall either gram positive or gram negative although all the steps in gram staining are crucial, the most important step the most crucial step in the performance of the Gram staining procedure is the decolorization step which is the Acid-Alcohol (3% HCl and 95% Ethanol) and must be timed correctly; the crystal violet stain will be removed from both Gram-positive and negative cells if the decolorizing agent is left on too long (a matter of seconds).


What happens if you forget to add acetone to a gram negative stain?

When performing the Gram stain, acetone is used as a wash step between the iodine and safranin. By not washing, all stains will remain crystal violet purple, and none will appear safranin red/pink.


T cells undergo positive selection in the thymus which means?

T cell undergoes maturation in the thymus and one of the tests it must pass to mature into a single positive mature naive T cell is positive selection. In positive selection your body is making sure that the T cell that it produces is reactive to your own MHC. If it cannot bind to your own MHC, the T cell is useless and it will just die by neglect in your thymus. In positive selection the T cell is "tickled" with thymic endothelial cells that express your own MHC class 1 and MHC class 2. If there is an affinity of the T cell to bind to your MHCs it will continue to the next step in maturation which is negative selection. If the T cell binds way too strongly to your MHC it will also die. There is a specific range that it must bind to your own MHC for it to continue.


What is the purpose of the decolorizer in the gram staining process?

The purpose of the decolorizer in the gram staining process is to remove the purple stain from Gram-negative bacteria, allowing them to be counterstained with a contrasting color. This step helps differentiate between Gram-positive and Gram-negative bacteria based on their cell wall composition.


List the steps of the gram-staining procedure in order and fill in the color of gram-positive cells and gram-negtive cells after each step?

____________Color of Gram-positive_______Color of Gram-negativePrimary stainCrystal violet_____Purple____________________ PurpleMordant:Iodine____________Purple________________________PurpleDecolorizing agent:Alcohol-acetone__ Purple____________________ ColorlessCounterstain:Safranin___________Purple_________________________Red

Related Questions

What is the first step of material charge?

positive and negative


What is 40 divided by minus 10?

30


Step by Step how to multiply negative numbers?

how to multiply negative numbers. 1. multiply the two numbers and first forget about the negative or positive signs. 2. Now look at the signs, if both numbers you multiplied were negative the answer is positive so what you have in step 1 above is the answer, if not, go to step 3. 3. One number is positive and one is negative so take your answer in step one and put a negative sign in front of it. 4. If there are more than 2 numbers, group them by pairs any way you want and follow this step by step for each pair.


What happen when you divide negative and positive number?

When you divide or multiply positive and negative numbers, you first do the division or multiplication as normal. The next step is to assess whether or not the answer will be negative or positive. If the two numbers of the question were the same (negative and negative or positive and positive) then the answer will be positive. If the two numbers in the question were different (one negative and one positive) then the answer will be negative. Thus, if you divide a negative number by a positive number, the result will be the same as normal division, but the answer will be negative.


Which step in the gram stain is the critical step in differentiating gram positive cells from gram negative cells?

Alcohol-acetone


What is Tests for Persistent Directional?

Mean step size - Number of positive and negative changes.


What is negative 100 divided by negative 4?

25


What is rule of addition of integers?

Rule: The sum of two negative integers is a negative integer.Rule: The sum of two positive integers is a positive integer.Procedure: To add a positive and a negative integer (or a negative and a positive integer), follow these steps:1. Find the absolute value of each integer.2. Subtract the smaller number from the larger number you get in Step 1.3. The result from Step 2 takes the sign of the integer with the greater absolute value.


How do you multiply a negative number with a positive fraction?

Any negative multplied to a positive is ALWAYS a negative answer, be it an integer or a fraction. Here is a table of multiplication/division of negative/positive numbers. X + = + X - = - X + = - X - = + If no sign is given before the numbers , then read it as positive (+). So (+) a X - b/c = - ab/c . (Note the negative in the answer!!!!!!


What is the first step of finding the sum negative 45 plus positive 36?

-9(I didn't use more than one step, I just added them together)


What does 2 times negative 4 times negative 7 equal and why?

In order to multiply two numbers together when one or more of them is negative, you start by multiplying them normally. In this case 4x7 = 28. The next step is to assess whether or not the answer is a negative or positive. If the two numbers being multiplied were the same (both negative or both positive) then the answer is positive. Otherwise, it is negative. In this case, we had -4 and -7 which are both negative, so the answer is positive 28. Thus the question can be rewritten as 2x28. This comes out as 56. Therefore 2 times negative 4 times negative 7 is 56.


What are the positive and negative effects of haiti?

Well, the positive affects are that the earthquake brought many countries closer, to help HAITI. That is one step closer to world peace.