i need help with question 3 and 4 please or just 4, kind of got 3 but just wante

Question

i need help with question 3 and 4 please or just 4, kind of got 3 but just wanted to confirm with my answer.thanks

Microsoft Word C https://blackboard.smcm.edu /bbcswebdav/pid-289431-dt-content-rid-1067681 1/courses/16FA-BIOL270.01.02/Biol270, 2016 Take Home Final pd he information listed below summanzes the current state of our knowl concerning Syndrome All o e data presented are real. The actual name of the syndrome has been fabricated so as not to deprive our students of the intellectual joy derived from utilizing the data to formulate responses to the questions that follow the summary given below a) Syndrome X is a human genctic disorder that results from a defect at one genctic locus and patients with the disorder manifest plciotropic effects that occur during cmbryonic develop These effects include ment. malformation of the anterior of the eye (which causes the eye disease known as glaucoma in 50% of Syndrome X patients mild head and face malformations and underdeveloped teeth. One of the pedig used to determine the mode of inheritance of the disorder is found belo b) Families displaying the disease were examined for linkage of the disease locus to a polymorphic site unique to each family. From such studies scientists were able to report linkage of the gene that is defective in the disorder to chromosome 4. (E rom this point on we will use the term "genc x" to designate the normal form of the gene that is defective in Syndrome X) c Investigators used positional cloning strategies, a methodology for isolating a cDNA clone coding for a gene when one knows nothing about the function of the protein encoded by the gene and has no probe for use in screening a cDNA library, and ultimately isolated a full length cDNA clone coding for the normal gene x. Subsequently, they isolated a human genomic clone coding for gene x. d) The cDNA clone as well as parts of the genomic clone were sequenced. The results are shown in Fig. 1 e) since nothing was known about the structure or function of the protein encoded by gene x, scientists deduced its amino acid sequence from the cDNA nucleotide sequence of gene x and used it for further studies. The deduced amino acid sequence was analyzed via software capable of predicting with some degree of accuracy, the secondary structure of a protein (but not the complete tertiary structure) and the presence of a helix-turn-helix was revealed. Mutant gene x isolated from members of 10 differen families diagnosed with Syndrome x were analyzed to identity the mutations therein. One family showed the following mutation. Nucleotide number 981 was changed from a G to an A as shown in Fg.1. The other nine families showed other distinct mutations. It is often helpful when studying human genetic disorders to have a mouse model ofthe disease as well as a mouse cDNA clone for the gene under study. or this reason, scientists isolated a mouse cDNA clone whose deduced amino acid sequence showed a 9 similarity to the deduced amino acid sequence for human genc Utilizing all of the data presented, in conjunction with the many concepts that you have learned this semester, answer the questions that follow. nahnyama

Explanation / Answer

I am referring to the question number 4 asking for the reasons for the change of protein sequence resulting due to mutation. I am sorry the uploaded photos are not clear and i dont understand them. but i will help you understand how the protein sequence changes with mutation of a nucleotide. I will give a general idea :)

In gene mutation, when one allele of a gene changes into a different allele, the gene mutation is called a point mutation. The point mutational changes that take place at the DNA level have an effect on the protein level.

At the DNA level, there are two main types of point mutational changes: base substitutions and base additions or deletions. Base substitutions are those mutations in which one base pair is replaced by another. Base substitutions are of two subtypes: transitions and transversions. A transition is the replacement of a base by the other base of the same chemical category (purine replaced by purine: either A to G or G to A; pyrimidinereplaced by pyrimidine: either C to T or T to C). A transversion is the replacement of a base of one chemical category by a base of the other (pyrimidine replaced by purine: C to A, C to G, T to A, T to G; purine replaced by pyrimidine: A to C, A to T, G to C, G to T).

Addition or deletion mutations are nucleotide pairs. The simplest of these mutations are single-base-pair additions or single-base-pair deletions.

As a result of such point mutations, there are functional consequences. In other words, change in the protein sequence. Such fuctional consequences caused as a result are:

Silent substitutions: the mutation changes one codon for an amino acid into another codon for that same amino acid.

Missense mutations: the codon for one amino acid is replaced by a codon for another amino acid.

Nonsense mutations: the codon for one amino acid is replaced by a translation termination (stop) codon.

Therefore the resulting protein sequence will change

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