Chemistry of replication, replication initiation, and DNA maintenance
Supplemental Instruction
Iowa State University / Leader: / Matt C.
Course: / Biol/Gen 313
Instructor: / Dr. Myers & Dr. Vollbrecht
Date: / 01/26/2017

Introduction: This worksheet discusses material covered in the sixth and seventh lectures (01/23/17 and 01/25/2017). Chapter 10 examines these topics.

Concepts

  1. RNA background.
  2. RNA transcription.
  3. RNA processing.

Material

  1. RNA background.

In this section, we’ll discuss the types of RNA and differences between RNA and DNA.

  1. Name the three most significant classes of RNA and what they’re used for.
  1. The smaller subclasses of RNA all act like a single one of the major classes. Which? How so?
  1. Why not just use DNA in the place of mRNA? Why don’t your cells use “mDNA?”
  1. RNA transcription.

Just like DNA replication, you’ll have a diagram and a set of proteins you’ll have to remember here. Since the proteins involved in RNA transcription are simpler, though, we’re also adding on the need to understand translation.

  1. What do promoters do?
  1. Here’s a diagram of an RNA-coding double-stranded DNA sequence from bacteria. Label the important parts of it. Include as much information as you can.
  1. What parts of the above diagram are transcribed? What does the mRNA look like?
  1. What are consensus sequences? How’re they used in bacterial promoters?
  1. What are the differences between an mRNA-coding region in bacterial DNA and one in eukaryotic DNA?
  1. What would happen to a bacterium if a mutation occurred which prevented its sigma factor from binding to the RNA polymerase complex? What would happen if a mutation prevented the sigma factor from releasing from the holoenzyme complex?
  1. Explain rho-independent and rho-dependent termination. What does the formation of an RNA hairpin do? Which termination method relies on A/T binding?
  1. RNA processing.

Here, we’re worried about processing of RNA post-transcription. Prokaryotes don’t do much of any of this.

  1. Why is it important to tag the 5’ end with methylated guanosine?
  1. Explain the process of adding the poly (A) tail. Why does this happen?
  1. What is the point of splicing?
  1. How many introns were in the pre-mRNA of the mature mRNA bound to DNA shown below? How do you know?
  1. There are 3 consensus sequences involved in splicing. What do they mark?
  1. How does the spliceosome work? What is the characteristic structure of excised introns?

Things to do next

  • Focus your review on things that were difficult from this worksheet. If it was really challenging, don’t worry; these are meant to be tough and push your understanding of the topics we covered.
  • The RNA-coding DNA diagram is important. Make sure you understand the parts there and how things would look different in a eukaryotic gene. It’s possible that you will be asked to distinguish consensus sequences. Spend some time memorizing those. Otherwise, the three big processes to know are transcription, termination, and splicing.
  • If you have any questions, ask me in session, in class, or by email. I’m more than happy to help.
  • Next session (Sunday 01/29/17) will be our exam review. I’ll post a practice exam and that’s what we will work off of. I won’t use any of the practice exams listed on Blackboard so that you all will have more material to study from independently, however; if you have any questions from those exams, I can answer them on Sunday.
  • Tuesday will be more review for anybody who hasn’t taken the test yet and we’ll finish covering anything not covered on Thursday for Exam 1, including lecture 8.