This document contains instructions and questions for a genetics homework assignment. It asks the student to: 1) Draw the structure of two base-paired dinucleotides and indicate relevant atoms and bonds. 2) Identify which of several pairs of mutations would have a greater consequence to a gene's function and explain why. 3) Analyze domain structures and mutations in a gene responsible for hearing and memory and explain the resulting phenotypes. 4) Describe the consequences of various mutations in a gene on transcript and protein production. 5) Briefly explain how a gene family can arise. 6) Discuss how the idea that ATP is not limiting in eukaryotic cells relates to the presence of intr

4. 4. Describe the fate of “the p1 protein” for each of the mutants listed. In the p1 protein the specific amino acids 1,2,3 and 6 are essential for function; amino acids 4 and 5 are “linker” and can be any amino acid. p1 synthesis requires DNA damage and the p53 enhancer (see below). Describe a likely consequence of each mutation; is a transcript made , is the transcript translated, how long is the translated protein, and the overall amount of functional protein in the cell. Bases in the TATA box that are essential for RNA polymerase binding are capitalized. Capital letters in the ORF are to help you identify the amino acids essential for function. Consult Genetic Code Table. You can answer with More, Less, Unchanged compared to wt. p53 binding site TATA box +1 12 TATAccg ggccaattgcg A TGGGCATA cccctg CCCTGA wild type YES YES 6 YES a. Deletion in the p53 binding site Less Less still 6 Less b. Mutation of TATA to TATtgca Less Less still 6 Less c. Base 12; A to C YES NO 0 NO d. ATA to ATT YES YES 6 YES e. ATA to TTC YES YES 6 NO f. cccc to tagc YES YES 3 NO g. Insertion c after g at +2 YES YES 6 YES h. ATG to TGA YES NO 0 NO Transcript Translated #AA Function p53 biology: p53 is a transcriptional activator, or enhancer. Without it, the RNA polymerase cannot transcribe the p1 gene very well. Note to class: c thru h was graded. 1pt each line.

5. 5. Describe briefly how a gene family arises. The gene family can consist of two genes with related but slightly different functions. First there was one gene. An error led to a gene duplication, so there were two identical genes. Then mutation occurs in one of them to alter function. 6. Discuss briefly the relevance of the idea that ATP is not limiting for many processes in higher eucaryotic cells for the presence of introns. A student pointed out that to transcribe 250kb, then delete most of the RNA to make a mRNA of 6 kb seems ‘wasteful” in terms of ATP..indeed, each nucleotide polymerized costs to make the NTP. We surmise, then that ATP is not limiting, otherwise introns would not be so huge and “wasteful” of the cells energy.