AQA Biology AS New Spec - 26th May and 7th June

it doesn't say anywhere in the new spec that we need to know about cholera specifically like the past specification. But i think it'll be good go gather a bit of knowledge on it just in case.

Does anyone know what is exactly meant by 'mass transport'?

Mass transport is the movement of a large number of particles (ions/molecules etc) in the same direction at a same time.

It's often due to pressure like in the phloem, during ventilation, and in circulatory systems, and can only happen with fluids. Hope this helped

so like easy papers can also have low-grade boundaries ?! is this hat ur trying to say ?if this is the case i still have hope for scoring at least a B on my biology paper 3 .

Could you explain it in the context of circulatory systems, as in how is it a feature of mass transport?

Hey guys... does anyone know how to do this question from the specimen Paper 2 (see attached)?? the answer is 78-81%, but I am not sure how to work it out...any help would really be appreciated!

At 1 second its approximately 4.1 for the healthy group and 0.9 for the other group so you need to find what % decrease that is. 4.1 - 0.9 = 3.2 which is the decrease. Therefore as a percentage its 3.2/4.1 x 100 = 78%

Could anyone help me understand Monoclonal antibodies? I really don't understand it & the ELISA test if someone could explain it using normal rather than overly scientific language i'd be grateful

Does anyone have a list of 5/6 mark questions which I could prepare for paper2?


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Does anyone know what is exactly meant by 'mass transport'?

Does anyone know what is exactly meant by 'mass transport'?

HERE WE GO.....


The
ELISA test has many uses as I am sure you already know. E.g/ cancer patients to attack tumor cells which are slightly different to normal body cells, transplant surgery - to attack the t-cells from the donor and to find antigens/antibodies:

There are two versions which are taught for our spec:
-The first is using a test tube/plate which has antibodies at fixed positions. In this test we are using the test to find antigens. An example is when we are looking for antigens related to cancer such as the prostrate specific antigen.

Step 1) We start off with the antibodies already on the plate.
Step 2) We add the blood sample from the patient. If the patient has lots of PSA (the cancer antigen) it will bind to the antibodies to make the antigen-antibody complex.
Step 3) If they form a complex then they will remain bound when the plate is washed. The reason for washing comes up later.
Step 4) Now we add another antibody, this antibody has a small enzyme attached to it. The antibody will bind to the antigen as well. So in effect, the antigen binds to two antibodies. We now wash to remove any antibody if it didn't bind. If there was no antigen present in the blood, then the antibody we added in this step would not bind as there is no antigen to bind to. This is what it kinda looks like:


|-< >- =Antigen in blood |-<= Antibody already on test plate
|-< >- =Enzyme on the second antibody
|-< >-
|-< >-

As you can see, in the first three. The second antibody will bind as the antigen is present. But on the last one, there is no antigen present so >- will be washed away and no colour produced.

Step 5) We add a substrate, this substrate will react with the enzyme to form an enzyme-substrate complex. Upon forming this, the enzyme breaks down the colourless substrate into a coloured product. So a coloured product is formed only if the antigen is present. We can know do quite a few things from this position. We can look at the intensity of the colour as a measure of the concentration of antigens in the persons blood as MORE ANTIGENS = MORE COLOUR or we can use a colorimeter to measure the conc.

The way to look for antibodies instead of antigens is similar but instead of starting with an antibody on the plate we start with an antigen.


As for monoclonal antibodies - all you need to remember is that the are a group of a single type of antibodies and that they have lots of uses. The formation of them is not on our, the new, spec.

Hope that helped

HERE WE GO.....


The
ELISA test has many uses as I am sure you already know. E.g/ cancer patients to attack tumor cells which are slightly different to normal body cells, transplant surgery - to attack the t-cells from the donor and to find antigens/antibodies:

There are two versions which are taught for our spec:
-The first is using a test tube/plate which has antibodies at fixed positions. In this test we are using the test to find antigens. An example is when we are looking for antigens related to cancer such as the prostrate specific antigen.

Step 1) We start off with the antibodies already on the plate.
Step 2) We add the blood sample from the patient. If the patient has lots of PSA (the cancer antigen) it will bind to the antibodies to make the antigen-antibody complex.
Step 3) If they form a complex then they will remain bound when the plate is washed. The reason for washing comes up later.
Step 4) Now we add another antibody, this antibody has a small enzyme attached to it. The antibody will bind to the antigen as well. So in effect, the antigen binds to two antibodies. We now wash to remove any antibody if it didn't bind. If there was no antigen present in the blood, then the antibody we added in this step would not bind as there is no antigen to bind to. This is what it kinda looks like:


|-< >- =Antigen in blood |-<= Antibody already on test plate
|-< >- =Enzyme on the second antibody
|-< >-
|-< >-

As you can see, in the first three. The second antibody will bind as the antigen is present. But on the last one, there is no antigen present so >- will be washed away and no colour produced.

Step 5) We add a substrate, this substrate will react with the enzyme to form an enzyme-substrate complex. Upon forming this, the enzyme breaks down the colourless substrate into a coloured product. So a coloured product is formed only if the antigen is present. We can know do quite a few things from this position. We can look at the intensity of the colour as a measure of the concentration of antigens in the persons blood as MORE ANTIGENS = MORE COLOUR or we can use a colorimeter to measure the conc.

The way to look for antibodies instead of antigens is similar but instead of starting with an antibody on the plate we start with an antigen.


As for monoclonal antibodies - all you need to remember is that the are a group of a single type of antibodies and that they have lots of uses. The formation of them is not on our, the new, spec.

Hope that helped

HERE WE GO.....


The
ELISA test has many uses as I am sure you already know. E.g/ cancer patients to attack tumor cells which are slightly different to normal body cells, transplant surgery - to attack the t-cells from the donor and to find antigens/antibodies:

There are two versions which are taught for our spec:
-The first is using a test tube/plate which has antibodies at fixed positions. In this test we are using the test to find antigens. An example is when we are looking for antigens related to cancer such as the prostrate specific antigen.

Step 1) We start off with the antibodies already on the plate.
Step 2) We add the blood sample from the patient. If the patient has lots of PSA (the cancer antigen) it will bind to the antibodies to make the antigen-antibody complex.
Step 3) If they form a complex then they will remain bound when the plate is washed. The reason for washing comes up later.
Step 4) Now we add another antibody, this antibody has a small enzyme attached to it. The antibody will bind to the antigen as well. So in effect, the antigen binds to two antibodies. We now wash to remove any antibody if it didn't bind. If there was no antigen present in the blood, then the antibody we added in this step would not bind as there is no antigen to bind to. This is what it kinda looks like:


|-< >- =Antigen in blood |-<= Antibody already on test plate
|-< >- =Enzyme on the second antibody
|-< >-
|-< >-

As you can see, in the first three. The second antibody will bind as the antigen is present. But on the last one, there is no antigen present so >- will be washed away and no colour produced.

Step 5) We add a substrate, this substrate will react with the enzyme to form an enzyme-substrate complex. Upon forming this, the enzyme breaks down the colourless substrate into a coloured product. So a coloured product is formed only if the antigen is present. We can know do quite a few things from this position. We can look at the intensity of the colour as a measure of the concentration of antigens in the persons blood as MORE ANTIGENS = MORE COLOUR or we can use a colorimeter to measure the conc.

The way to look for antibodies instead of antigens is similar but instead of starting with an antibody on the plate we start with an antigen.


As for monoclonal antibodies - all you need to remember is that the are a group of a single type of antibodies and that they have lots of uses. The formation of them is not on our, the new, spec.

Hope that helped