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Biology · 2024 · 3 marks
CBSE 2024 · Region 1 · Set 2 · Q26
Given below is a picture that shows the magnified blood smear of a patient under a microscope. (a) Name the disease the blood smear is indicative of.…
Given below is a picture that shows the magnified blood smear of a patient under a microscope.
(a)
Name the disease the blood smear is indicative of. Write the symptoms of the disease and its cause.
(b)
Explain the inheritance pattern of the disease with the help of a suitable cross.
Marking-scheme solution
(a)
Sickle cell Anemia
Cause – Substitution of glutamic acid by valine at sixth position of beta globin chain of haemoglobin molecule / due to single base substitution at the sixth codon of the beta globin gene from GAG to GUG.
Symptoms– Change in shape of RBC from biconcave disc to elongated sickle like structure causes anemia due to which oxygen carrying capacity of the RBCs decreases / tiredness/ breathlessness
.
(b) Autosomal recessive genetic disorder. Controlled by pair of allele HbA HbS
HbA HbS
× HbA
HbS
(carrier male) (carrier female)
HbA
HbS
HbA
HbAHbA
Normal
HbAHbS
Carrier
HbS
HbAHbS
Carrier
HbS HbS
Affected
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