Formative Practice 10.5 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
State the blood group which is the universal donor.

Blood group O

Question 2:
Predict what will happen if the blood group of both recipient and donor is not compatible.

The blood of the recipient will undergo agglutination.

Question 3:
Three babies P, Q and R have blood groups B, O and AB respectively. Three pairs of parents have the following blood groups:

The first pair of parents: B and O
The second pair of parents: A and B
The third pair of parents: AB and O

Match the babies with their correct parents.


Question 4:
An Rh-positive male marries an Rh-negative female. The first Rh-positive child is alive but the second child who is also Rh-positive did not survive. Explain why.

• In the final month of pregnancy, fragments of the first child’s blood cells that has Rhesus antigen mixes with the mother’s blood through the shedding placenta.

• This induces the mother’s immune system to produce antibodies against the Rhesus antigen.

• The antibodies (anti-Rhesus) formed flow across the placenta into the fetal blood circulatory system.

• Normally, the quantity of antibodies formed is not enough to affect the firstborn.

• However, the antibodies that can destroy red blood cells remain in the mother’s blood.

• When a second child is conceived, which is also Rhesus positive, a small amount of fetal blood that enters the mother’s blood will induce more anti-Rhesus secretion.

• Antibodies that diffuse into the fetal blood circulatory system will destroy the fetal’s red blood cells

• The fetal’s red blood cells experience haemolysis.

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