1. A cell must duplicate its DNA so the daughter cell with have the same about of identical DNA
2. Mitosis
Hope this helps
Answer: Structural chromosomal mutation
Explanation: In translocation, a small piece of chromosome is detached from one chromosome and is attached to another non-homologous chromosome. Translocation can be simple, shift or reciprocal.
Simple translocation involves single break in the chromosome. The broken piece gets attached to the end of the non-homologous chromosome.
In Shift translocation, the broken segment of one chromosome gets inserted interstitially in a non-homologous chromosome.
Segment from one chromosome is exchanged with a segment from another non-homologous chromosome simultaneously in Reciprocal translocation.
Answer: All the statements of the question are correct.
Sickle cell disease is an autosomal recessive disorder that is characterized by formation of defective hemoglobin protein, which results in sickle shaped RBC ( red blood cell).
This disease is caused by mutation in the gene that is responsible for the protein hemoglobin ( which transport oxygen throughout body).
It is inherited by the offspring when both the mutated copy of genes ( one from each parent) are passed to him.
Carriers of the disease exhibit increased resistance to malarial parasites by controlling the level of free haem in the blood ( through enzyme heme oxygenase that produces a toxic carbon monoxide gas). The resistance thus developed, is a mutation.
Therefore, all the statements in the given question are correct.
Answer:
(a) 1/2; (b) no
Explanation:
Glucose-6-phosphate dehydrogenase deficiency (G6PD) is an X-linked recessive disorder and the woman's father was diseased so it means that woman is a carrier of the allele but has normal phenotype. It means that she will have XXᵇ genotype.
In contrast to this, her husband is diseased so his genotype will be XᵇY.
The Punnett square diagram related to the cross is attached.
(a) Proportion of their sons expected to be G6PD is 1/2:
They both may give birth to 4 progeny with genotypes XXᵇ, XᵇXᵇ, XY and XᵇY. It means they both may have 2 sons out of which one with genotype XᵇY will be diseased while the one with genotype XY will be healthy. So the proportion of their sons having G6PD is 1/2 or 50%.
(b) If the husband were G6PD deficient, the answer will not change.
The reason behind this is that this disease is caused by an allele located in X chromosome. But father contributes only Y chromosome to his son not X chromosome. The X chromosome will affect the genotype of his daughter not son that is why answer will not change. It means they will still have 1/2 of their sons diseased.
