<p>Hey guys, I have a question and ask you for some help? </p>
<p>I still donāt quite get 3. line of defense (specific defense) of our immune system. What exactly is the humoral response? Do B cells engulf the antigens and bring them to their surface so that helper t cells can bind to them? If so, what is the cell-mediated response?
Barronās says: T.lymphocytes. These fight pathogens by hand-to-hand combat in what is called a cell-mediated response. </p>
<p>So letās just say an pathogen is not disabled by the first two lines of defense. What happens to it? Do B or T cells enable it? </p>
<p>Itās much more complicated than the SAT2/AP level which is why, IMO, they donāt talk much about it.</p>
<p>In any event, the humoral immune response is the response to specific antigens.</p>
<p>Certain cells like macrophages and dendritic cells phagocytose foreign substances and then express on their surface self and non-self markers. (Basically they bind to the MHC, major histochemical complex.)</p>
<p>If the markers are a mix of self/ non-self, the T-helper cell matured in the thymus is activated and divides into THelper Cells, Cytotoxic T cells and memory t cells. Cytotoxic t cells basically destroy non-self entities. Memory T-cells hang around until the next use. </p>
<p>(This is specifically called the humoral response:
Then, (usually), the T Helper cells stimulate B-cell production. Two types of B cells are made: plasma cells and B-memory cells. The former just replicates and makes a tonne of antibodies that bind to non-self bacteria. The stimulation of B cells works through cytokines (specifically, interleukins). </p>
<p>There are lots of lymphocytes include Natural Killer-T cells and specific lineages but I donāt really think we need to know all of that.</p>
<p>Thank you! it does make sense. I am sorry to bother you again but what exactly is the cell-mediated response? Natural killer t cells killing antigens?</p>
<p>Hi guys! just 2 days to go!
I havenāt taken up Bio in 11th and 12th. So, I just prepared from PR, Barrons and sparknotes. Any other book suggestions? I am willing to do some last minute preparation.
Also the thing about cladograms, it wasnāt even covered by Barrons but another book called Petersons. Or rather, it was asked in one of its practice tests. It is like a phylogenetic tree.The position of species on the line tells us how closely related they are.</p>
<p>There are some terms like āoutgroupā etc. that you might want to check out.
Btw, this book, petersons, has barely any study material but practice tests that are a hundred times tougher than Barrons!</p>
<p>I would really appreciate it if you guys could suggest books/practice tests. Any online material since it is too close to the test date. And also, are there any important things that are not covered by Barrons other than the Phosphorous cycle?</p>
<p>And yeah, if time permits, can we mark all answers for all the 100 questions and, in the end, decide to darken either the Bio E or Bio M circle. Is it necessary to erase the circles of the sub-section that one isnāt attempting.</p>
<p>@book05, sorry if I didnāt make it clear enough:</p>
<p>the T-cell bit is the cell mediated response</p>
<p>the B-cell bit is the humoral response.</p>
<p>Together, they make the secondary immune response carried out by lymphocytes.Itās also called the āthird line of defenceā or āadaptive immunity.ā</p>
<p>I went through CliffsAP first and am now going through Barrons as final prep. Previously I did just Barrons but I think it helps to know both.</p>
<p>Idk about tests though, sorry. Thanks for the cladeogram link! </p>
<p>Make sure you know the weird ecological graphs btw.</p>
<p>Hey! finished the test about 12 hours back! it was pretty good. So, the cladogram did appear! Btw, is the test the same for international areas and the US?</p>
</p>