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Chapter 13 Blog: Gene Regulation (Philip)

Page history last edited by Philip Wang 13 years, 3 months ago

In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.

 

A.  Daily Blog

In class, we learned about the importance of gene regulation. There are two main reasons why gene regulation is important: it conserves energy and it helps with cell differentiation. Activator proteins essentially lower activation energies while repressor proteins increase it. Small effector molecules cause conformational changes. Prokaryotes have operons, which are clusters of two or more genes under a single promoter. Polycistronic mRNA contains coding sequences for two or more genes. The lac operon contains genes for enzymes that allow it to metabolize lactose. The lacP is the promoter, which also contains lacZ, lacY, and lacA. The lacO is the operator, which provides the binding site for repressor proteins. The CAP site is the binding site for the activator protein. The lacI gene codes for the lac repressor. Eukaryotes have activator and repressor proteins that influence the ability to initiate transcription. They also have small effector molecules. What makes them different from prokaryotes is that they lack operons, which means their genes are organized individually. Also, the general regualtion is more complex. Combinaterial control is when one or more activator/repressor proteins may stimulate/inhibit the ability of RNA polymerase to initiate transcription. Activator proteins are necessary to unwind chromosomes for transcription and DNA methylation inhibits transcription. There are three features in promoters. The TATA box determines the starting point of transcription. The transcriptional start site is where transcription begins. It forms the core promoter with TATA box and this results in low level basal transcription. The regulatory elements enhance/diminish transcription and consists of enhancers and silencers. Three proteins are needed for transcription: RNA polymerase II, 5 different transcription factors, and a large protein complex called a mediator. There are three ways to control RNA polymerase II. Activators and repressors regulate the function of RNA polymerase II by binding to general transcription factors or the mediator. The activator binds to the enhancer to recruit transcription factors. Control of the RNA polymerase II is via the mediator. Activators stimulate the function of the mediator by allowing faster initiation repressors to inhibit the mediator to stop elongation. Lastly, proteins that influence DNA packing are recruited.

 

B.  Useful Materials

This is a video that tells about the lac operon and how prokaryotes use it to regulate gene expression.

 

This is a video that tells about how transcription is regulated.

 

http://www.biotecharticles.com/Genetics-Article/Gene-Regulation-by-Minerals-and-Vitamins-193.html

 

This is an article on gene regulation by minerals and vitamins. It tells about how minerals and vitamins found in our bodies also involve gene regulation.  

 

Comments (1)

Derek Weber said

at 12:47 am on Feb 16, 2011

Need more detail in your item summaries. Please see the syllabus.

Use the learning objectives as a guide when writing your chapter summary.

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