Question

3. In the event of a bacterial contamination in cell culture the easiest thing to do is_ and why? a. Discard the cells and have a new thaw frozen vial of fresh cells b. Simply add antibiotics to kill the contaminant c. Keep the culturing like nothing happened d. Wash the cells several times with PBS 4. What are ABO antigens? 5. Describe the immunological reaction that occurs in the Erythroblastosis Fetalis?

can u please help me with question 3 and explain the answer. Also, question 4

Answer 1

Q.3 In an event of bacterial contamination in cell culture, the easiest way is to discard the cells and have a new thaw frozen vial from fresh cell. This will easiest method. One can use antibiotics but they should be used for irreplaceable sample( if one don't have frozen vials) but antibiotics may and may not save it , it take considerable effort and chances of success is rare and in future can sometime lead to problems. But if you have preserved stock you can use it.Because their are no chances of contamination. If you left flask after contamination as such bacterial contamination will kill all your cells and also spread to your other experimental media's and chemicals. Best thing is to discard it. If you wash cdlls with PBS it will simply wash wastes of cell and provide some nutrients to cell it do nothing with contamination. It doesn't remove contamination. So option a) is right choice of this question.

Q.4 ABO antigens are antigen who's presence or absence on surface of erythrocytes determines the blood group in human. The antigens are A and B which determines the A, B, AB and O blood group.

Person having A blood group have A antigen present on surface of it's erythrocytes. Similarly B blood group person had B antigen, person with AB blood group has both A and B antigen preent on its erythrocytes and person with O blood group doesnot have neither A not B on surface of it's erythrocytes. Similarly antibodies are also produced in every four above blod group cases as shown below in table

Blood group	Antigen present	Antibody produced
A	A	B
B	B	A
AB	A and B	-
O	-	A and B

Q.5 Erythroblastosis felatis is a disease caused due to blood group incompatibility between mother and foetus. In this RBC of foetus are destroyed by mother's antibody leading to anemia in foetus. It is due to inheritance of Rh factor in foetus from father that in not present in mother. It can even lead to death of foetus. You can understand it in better way from diagram drawn below.As shown in figure Rh factor incompatibility.

During Preana At deleiary Month i lasta RW positive antibodies Loetus Rh positive male (Father) Rh negative female (Mother) Rh-positive Rh+) baby's blood cells enter motherle bloodstream These cells lead to production of Rh KI antibodies antibodies and bodies Femain tv- mother's blood - SACAS Rh positie antibody kill Rh. Positive baby's blood cells Late with baby pregnancy Rh positive

When Rh positive father and Rh negative mother have a Rh positive baby, then baby cells are Rh positive. No immune response occur towards this baby by mother's immune system. At the deleivery when baby born some cells of baby enter in mother blood so mother immune system recognise it as foreign and produce antibodies against Rh factor. At the time of later pregnancy if mother have a Rh positive foetus antibodies of mother react and destroy erythrocytes of baby containing Rh factor leading to anemia or even death of baby.

So Rhogram injection is given by doctors in case of such incompatibility so save baby.