Tag: blood group

Rh incompatibility arises when mother and the baby carries different protein factors. The problem arises when mother is Rh negative and the child she is carrying is Rh positive. This can take place even when two blood groups with different proteins are either mixed in a test tube or transfused into a person. Rh negative people do not have this protein and if Rh positive blood is mixed with Rh negative blood anti Rh antibodies develop which can lead to problems. 

Erythroblastosis fetalis also called the hemolytic disease of the newborn, type of anemia in which the red blood cells (erythrocytes) of a fetus are destroyed in a maternal immune reaction resulting from a blood group incompatibility between the fetus and its mother. Symptoms of erythroblastosis fetalis range from mild to severe; death of the fetus or newborn sometimes results.

The Rh system is responsible for the most severe form of the disease, which can occur when a Rh-negative woman (a woman whose blood cells lack the Rh factor) conceives a Rh-positive fetus. Sensitization of the mother’s immune system (immunization) occurs when fetal red blood cells that carry the Rh factor (an antigen in this context) cross the placental barrier and enter the mother’s bloodstream. They stimulate the production of antibodies, some of which pass across the placenta into fetal circulation and lyse, or break apart, the red blood cells of the fetus (hemolysis). Hence option B is correct.

There are two main causes of erythroblastosis fetalis: Rh incompatibility and ABO incompatibility. Rh incompatibility occurs when a Rh-negative mother is impregnated by a Rh-positive father. The result can be a Rh-positive baby. In such a case, your baby’s Rh antigens will be perceived as foreign invaders, the way viruses or bacteria are perceived. Your blood cells attack the baby’s as a protective mechanism that can end up harming the child. If you’re pregnant with your first baby, Rh incompatibility isn’t as much of a concern. However, when the Rh-positive child is born, your body will create antibodies against the Rh factor. These antibodies will attack the blood cells if you ever become pregnant with another Rh-positive baby.

Erythroblastosis foetalis is a disease of the new born which is caused by Rh incompatibilty. This happens when mother is Rh negative and the child she is bearing is Rh positive. Thus the Rh antigen of child can trigger the antibodies inside mother which can travel through circulation thus destroying foetus blood cells. Thus, correct answer is option D.

Alleles are alternative forms of a gene. They are responsible for differences in phenotypic expression of a given trait. When a gene exists in three or more allelic forms it is called multiple allele. Homologous chromosomes are chromosome pairs, one from each parent. They are similar in length, gene position and centromere location. Multiple alleles are situated in homologous chromosome at the same locus. Thus the correct answer is option A.

Albinism is a autosomal genetical recessive gene disorder. It occurs in homozygous recessive state. The gene for albinism is a. it does not produce the enzyme tyrosinase, but is normal Allele A is does. Thus only homozygous individuals (aa) is affected. When both parents are albinic, all the offsprings also albinic generally.

So, the correct option is ‘Albino’.

When heterozygotes have a selective or reproductive advantage (overdominance or heterozygote advantage), alleles for both dominant and recessive traits are maintained in the gene pool, ensuring both homozygous genotypes continue to appear in future generations.