The nonmutant allele of the brca1 gene to suppress tumor formation in women who are heterozygous for the mutation. women heterozygous for brca1 nevertheless have a 50% to 70% chance of developing breast cancer before age 70, and the usual reason is that the nonmutant allele is lost or inactivated in a lineage of cells. one possible mechanism for such "loss of heterozygosity" is:
a. germ cells in the affected individual develop a mutation in the nonmutant allele of brcal.
b. a somatic mutation in a breast cell inactivates the nonmutant brca1 allele.
c. a silent mutation occurs in the nonmutant brca1 allele.

Option B

Explanation:

A silent mutation has no effect on the gene activity and function hence option C is incorrect. Germ cells would affect the gametes produced, not the body's proteins hence the answer would be B.

the cytokine-activated janus kinase (jak)-signal transducer and activator of transcription (stat) pathway has an important role in the control of immune responses. dysregulation of jak-stat signaling is associated with various immune disorders.

you are certainly talking about this picture:

a: is the label of the white square, it is showing the  replication fork, formed by helicase (d) ==> so it is the site of dna separation and replication 

b: is a new dna brand that is following directly the replication fork, so it is continuous ==> built continuously from 5' to 3

c: dna polymerase cannot replicate dna on its own, it needs the of their proteins, and one of them plays the role of a clamp which fixes  the dna with the dna template and increases  the processivity of the enzyme. ==>   stops polymerase from falling off the  template.

d: is the enzyme responsible for forming the replication fork (helicase) ==> unwinds and separates dna into two strands

e: is the delayed strand, it is built  in the opposite sense of the helicase, so dna will be built in fragments ==> built  fragments from 5' to 3 joins

and finally f: is the enzyme that builds  the new dna strand (dna polymerase) ==>   adds nucleotides to make a new dna helix.

credit: gradman555p98x9p

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