Biology Test

d) Propose three features of a model to connect the genetic mutation you predicted with the activity of the signaling pathway involving a LDS2B gene product.

-Change in the genetic sequence may decrease the function of the signaling pathway -It also might activate signaling instead -Will cause a structural change in the polypeptide

c) One genetic change associated with the disorder results in a methionine to valine substitution at amino acid 425 of the encoded polypeptide, as shown in Figure 1. Predict the DNA mutation that will result from this substitution.

AUG-> GUG

Short Answer- a) Based on a pedigree of a family in which one parent has Loeys-Dietz syndrome, a researcher claims that the disorder is an autosomal dominant condition. Describe TWO characteristics of the pedigree that would support this.

-The characteristic is likely to be autosomal if it is inherited equally by males and females -Evidence to support dominant inheritance is if each individual has one or more affected parent.

b) Calculate the minimum number of nucleotides required in the coding region of the LDS2B mRNA molecule to produce and terminate the 565-amino acid polypeptide. Provide two reasons that the number of nucleotides in the mature mRNA may differ from the number of base pairs in the gene.

Calculations: 565 x 3= 1695 (Because there is a triplet code in the production of polypeptide) Reasoning: -Introns are removed from the mRNA but remain in the gene structure -The gene has regulatory enhancers such as promoters that are not transcribed