Antibodies

Question 1

Antibodies

Answer 1

+Proteins with specific binding sites synthesised by B cells.
+When a body is infected, antibody reacts with the antigen.
+Each antibody has two identical binding sites and are complementary to the antigen.
+Made from 4 polypeptide chains.-
1 pair= Heavy chain
1 pair= Light chain
+Forms antigen-antibody complex
+The binding site is different in different antibodies= Variable region
+The rest of the antibody= Constant region
(Receptor binding site)

Question 2

How the antibody leads to the destruction of the antigen

Answer 2

+Do not destroy antigen but prepare it for destruction
–eg; bacterial cell–
+Cause the agglutination of bacterial cells. This causes the Bac cells to clump and makes it easier for phagocytes to find them.
+Act as markers that stimulate phagocytes to engulf the bacterial cell.

Question 3

Monoclonal antibodies

Answer 3

+An antibody that produced by a single clone of cells or cell lines

Question 4

Targeting medication to specific cell types by attaching a therapeutic drug to an antibody.

Answer 4

+eg- cancer cells
Method 1=
-Monoclonal antibodies that are specific to the cancer cells are produced
-Given to the patient and they attach themselves to the cancer cells.
-They attach to the cancer cells and block the chemical signals that stimulate their uncontrollable growth.
eg; herceptin to treat breast cancer.
+ Since antibodies are non toxic and highly specific, they cause less side effects.

Method 2=
-Attaching a radioactive or cytotoxic drugs to the monoclonal antibody.
When it attaches to C cell, it kills it.

Question 5

Medical diagnosis

Answer 5

Eg- Men with prostate cancer have high levels of the antigen PSA in their blood. The usage of the antigen that reacts with PSA, we can get the level of PSA in blood.

Question 6

Pregnancy testing

Answer 6

+Placenta produces a hormone called Human Chorionic Gonadatrophin(hCG)
+M A that attach to hCG is on the test strip. If present the colour complex moves along the strip and is trapped by another antibody.

Question 7

Ethical use of monoclonal antibodies

Answer 7

+Production of monoclonal antibodies involves the use of mice. The production of tumour cells in mice involves deliberately inducing cancer in them.
+There have also been some deaths associated with their use in treating multiple sclerosis. Informed consent is important.
+Testing for new drugs includes certain dangers.