6.3b & 11.1a Defense Against Disease
18/11/2013 § Leave a comment
But mommy, I don’t want to go to school today.
DATA BASED QUESTION
Page 233, use of monoclonal antibodies to diagnose pregnancy
1. Explain how a blue band appears at point C if the woman is pregnant. –> Okay, so a pregnant woman would produce the hormone HCG. Upon taking the pregnancy test, the antibodies in the test attached to enzymes bind to the HCG molecules. The urine necessary for the test continues to wash the HCG molecules up into the test zone (point C) where they will bind with other antibodies who, in response, will do a chemical reaction involving changing colour.
2. Explain why a blue band does not appear at point C if the woman is not pregnant. –> If a woman isn’t pregnant, though the urine still washes up the test to point C, there are no HCG hormone molecules that can bind to the antibodies in the pregnancy test that will cause the colour change reaction.
3. Explain the reasons for the use of immobilised monoclonal antibodies at point D, even thought they do not indicate whether a woman is pregnant or not. –> Point D is the control, which tells the user if the test worked or not. Whether or not the test is a positive or a negative, point D should always change colour.