The file called "genetics2" contains the original assignment with the background information and questions to be solved. Files Unit+4+notes and Unit+5+notes contain more extensive background information, which is not directly related to the assignment. The attached file 407374Instrucations contains the original questions and advise on answering these questions (in blue ink). This solution is also pasted as a simple text here.© BrainMass Inc. brainmass.com October 25, 2018, 5:07 am ad1c9bdddf
III) Please answer the following questions. IMPORTANT: When referring to specific
nucleotides, give the letters of the bases (A,C,G or T), as well as their numerical positions in the original DNA sequence. For questions 1-6, please just give me the bases and their numbers, or the range of bases--don't include the question or add any editorial material. (Ex."GAC at 234, 235, 236" or "pre-mRNA = 456-879" if I am asking for a range of nucleotides).
1. a. How many nucleotides in the entire sequence entry?
Answer: As it is indicated in the introductory part, there are 2052 nucleotides
b. How many exons are in the gene?
Answer: You can see from the scheme there are 3 exons, which are labeled with E1, E2, E3.
c. How many introns are in the gene?
Answer: You can see from the scheme there are 2 introns, which are labeled with I1 and I2
To help you answer later questions, please highlight the three exons.
2. Transcription is initiated by the binding of transcription factors to the promoter region at the front end of the gene. The promoter region usually includes a variable number of nucleotides that lie in front of exon 1, and often includes approximately the first third of exon 1. Transcription factor binding sites sometimes have characteristic sequences. Among these are what people cutely call the "cat box motif," which involves the nucleotides C, A and T in some arrangement that spells out CAT or something like it, examples: CAAT, CCAATT, CATAAAA. Please identify two sequences that might serve as "cat box" promoter sequences. First remind ...
The solution addresses nine questions covering the process of transcription, splicing and translation of the human beta-globin gene. First, the solution discusses the meaning and the function of a promoter in transcription initiation. Then, we talk about the generation of the mRNA transcript, and the splicing process. Next, we cover the translation initiation and the importance of specific amino acids for the protein function. We learn how to work with the sequence provided in GenBank to identify the coding sequence of the gene.
Transcription in Eukaryotes
1. a. What unit is considered to compose the first order of chromatin folding in eukaryotes?
b. Define the terms "heterochromatin" and "euchromatin."
c. Why is transcription control necessary in eukaryotes?
2. a. List the three types of RNA polymerase enzyme, and for each, give the RNA molecule type it produces.
b. What are the three components of a preinitiation complex?
c. Describe the promoter sequence recognized by RNA polymerase II. Why might it be more complex than the other two promoters?
3. Take any RNA polymerase and describe the sequence of events of transcription of a specific DNA sequence. Include the assembly of the preiniation complex through elongation to termination.
4. a. Describe two post-transcriptional mechanisms.
b. What is the purpose of such mechanisms?
c. What is R-looping?
5. Consider the whole process of transcription in both eukaryotes and prokaryotes. Compare and contrast the two mechanisms in detail.