AQA BIOL1 ~ 14 May 2012 ~ AS Biology

Original post by scratcher

Can anyone help with this, it's from an old spec question june 05.

Describe how antibodies are produced following a viral infection? (6marks)

Mark scheme:
1. virus contains antigen;
2. virus engulfed by phagocyte/macrophage;
3. presents antigen to B-cell;
4. memory cells/B-cell becomes activated;
5. (divides to) form clones;
6. by mitosis;
7. plasma cells produce antibodies;
8. antibodies specific to antigen;
9. correct reference to T-cells/ cytokines;

So the question is, should point 3 say present to T cells, as antigen-presenting cells are cell mediated response which is T cells?

Thanks

no as that is a secondary response. you should mention memory T cells as well thoguh.

Reply 582

Original post by 4MANU4EVER4

it is 85 x 93.

This is because you take the highest volume of blood 148cm3 - the lowest 55cm3 as this difference shows how much blood is pumped out by the ventricle.

Pls cud u answer mine

Do we have to know how monoclonal antibodies are formed?

i have.

Reply 583

4MANU4EVER4

4

Original post by AlligatorSky

If you need antibodies to a specific antigen (lets say antigen X)

You will inject a mouse with X.

The mouse's B cells will produce poly clonal antibodies, which are removed from its spleen.

These B cells cant divide outside the body, so they are mixed with cells that do divide outside the body like cancer tumor cells.

To fuse the 2 cells together, detergent is added. this breaks their membranes and they join.

The fused cells are separated and each cell is cloned. (Each clone is tested to see whether it produces the right antibody)

If there ARE cells that produced the required antibody, theyre grown on a large scale

Because they are cloned from a single cell, they are called Monoclonal.

They need to go through a process called humanization so that that they work on humans.

Thank you so much!!!

Reply 584

HopefulFutureMedic

Original post by 4MANU4EVER4

it is 85 x 93.

This is because you take the highest volume of blood 148cm3 - the lowest 55cm3 as this difference shows how much blood is pumped out by the ventricle.

Pls cud u answer mine

Do we have to know how monoclonal antibodies are formed?

Aaaah! Right, i see :smile:

Cheers.

And yes i shall return the favour :wink:

•How are monoclonal antibodies made?

A mouse is exposed to foreign material, against which antibodies are required. B cells in the mouse produce a mixture of antibodies and then the B cells are extracted from the spleen of the mouse; they are then mixed with cells from a cancer tumour so the B cells can divide outside the body. Detergent is added so the cell surface membranes of both cells break down and they can fuse together. The fused cells are separated and each cell is cultured to from a group. Each clone is tested to see whether it is producing the required antibody. Any clone producing the correct antibody is cultured on a large scale and its antibodies are extracted. However as these antibodies came from a mouse, they need to be humanised before they can be used on humans.

Thats all you need to know and well the ethical issues concerning it

(edited 11 years ago)

Reply 585

Original post by 4MANU4EVER4

Thank you so much!!!

np.

Reply 586

Original post by AlligatorSky

If you need antibodies to a specific antigen (lets say antigen X)

You will inject a mouse with X.

The mouse's B cells will produce poly clonal antibodies, which are removed from its spleen.

These B cells cant divide outside the body, so they are mixed with cells that do divide outside the body like cancer tumor cells.

To fuse the 2 cells together, detergent is added. this breaks their membranes and they join.

The fused cells are separated and each cell is cloned. (Each clone is tested to see whether it produces the right antibody)

If there ARE cells that produced the required antibody, theyre grown on a large scale

Because they are cloned from a single cell, they are called Monoclonal.

They need to go through a process called humanization so that that they work on humans.

do you really need to know that? it isnt in the revision guide. (ive taught myself from the revision guide, had no lessons)

Reply 587

Original post by sconter

do you really need to know that? it isnt in the revision guide. (ive taught myself from the revision guide, had no lessons)

Sadly, yes you do.
Sometimes they ask that in the 5 marker question, so you need to know the correct sequence and everything.

But if you read through it a few times, it will make sense and it'll stick in your head.

Reply 588

Original post by AlligatorSky

Sadly, yes you do.
Sometimes they ask that in the 5 marker question, so you need to know the correct sequence and everything.

But if you read through it a few times, it will make sense and it'll stick in your head.

yea, will do
thanks!!

Reply 589

HopefulFutureMedic

Original post by Jakez123

stroke volume is the volume of blood pumped out of the heart in 1 cardiac cycle, to work it out you take the maximum volume from the minimum volume

148-55=93cm^3

therefore 93 x 85.7 = cardiac output

Thank you!!

Reply 590

username605217

10

Just saw a question in old spec: Describe how the antibody gene could be isolated from an animal cell and introduced into a crop plant such as maize?

Do we need to know this?

Reply 591

Original post by sconter

yea, will do
thanks!!

Reply 592

HopefulFutureMedic

Im getting STRESSED OUT!!!!!!!!!!!!

Reply 593

EmilyBea

1

Original post by AlligatorSky

Sadly, yes you do.
Sometimes they ask that in the 5 marker question, so you need to know the correct sequence and everything.

But if you read through it a few times, it will make sense and it'll stick in your head.

are you sure?! its not on the spec! you just need to know what they do/why they're used i thought?!

Reply 594

Ricky1995

Help on this question..

"Describe how maltose in the small intestine is digested, absorbed and transported to the liver as
glucose. " (7)

Reply 595

Original post by EmilyBea

are you sure?! its not on the spec! you just need to know what they do/why they're used i thought?!

My teacher said we do need to know them.
We spent like a whole lesson on them, so they should be important, unless its just my teacher.

Maybe you dont need to know it in that much detail but im pretty sure you need to know how theyre made.

Reply 596

username570910

2

Original post by sconter

yea, will do
thanks!!

You don't need to know how they're made. All you need to know is "The use of monoclonal antibodies in enabling the targeting of specific substances and cells" (From the AQA specification)

Reply 597