A man who smokes heavily has developed lung cancer. The tobacco smoke has caused mutations in some of the cells in his lungs, ma
king them unable to stop reproducing and dividing. He is worried that his children, none of whom smoke, may have inherited the lung cancer from him. Under what circumstances might his concern for his children be justified? A. If his smoking had already mutated the DNA in the cells in his lungs at the time his children were conceived, the mutations would have been passed to his children. B. If he inherited a mutation which made him more susceptible to lung cancer, it may have been present in some of the gametes he produced and passed to his children. C. If the mutation resulted from the duplication of a gene in his lung cells, his children would be at greater risk than if it were caused by a base pair substitution. D. If the smoke had caused multiple different mutations in his lung cells, it would be more likely that one or more of the mutations would be passed to his children.
The correct answer is: B. If he inherited a mutation which made him more susceptible to lung cancer, it may have been present in some of the gametes he produced and passed to his children.
Explanation:
The inheritance of genes from the parents to the offspring is mediated by the germinal cells or sex cells or gametes of the parents.
The genetic material present in the somatic cells of the parents are not transmitted to the offspring.
In the given case, the man who develops lung cancer generates some tobacco smoke induced mutations in some of the cells of his lungs.
The cells of the lungs are type up of somatic cells. Hence, any mutations in the genome of these cells will never be transmitted to the offspring.
Therefore, the children of the man will never become prone to develop lung cancer due to development of mutations in the lung cells of the man.
However, if the man has inherited any mutation from his parents which can increase the risk of development of lung cancer, then these mutations will be present in his germinal cells and also in some of his gametes.
Now, if a child is born due to the fusion of the the maternal gamete with one of these mutated paternal gametes, there is an increased chance of developing lung cancer in the child, irrespective of the fact whether he is a smoker or a non-smoker.
The cell is in METAPHASE PHASE OF MEIOSIS. At this phase, the pairs of homologous chromosomes moves to the cell equator. These pairs of homologous chromosomes will be separated in anaphase I. The number of chromosomes remains constant until the first cell division is completed, then the chromosomes will be divided into two daughter cells.
