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

     Gene regulation is the ability for cells to control their level of gene expression. Cells need to only express genes when the need them. Otherwise, way too much energy would be wasted. It also ensures genes are expressed in appropriate cell type and at the correct stage in development. The genomes of every cell in the body is the same, but they all function differently because the proteomes are different.

     In prokaryotes, gene regulation is used to respond to the changes in the environment. In eukaryotes, gene regulation produces different cell types in an organism or cell differentiation, as explained above.

     Activator proteins can increase the rate of binding (or the binding constant). They can also increase the rate of strand opening. The end result is more RNA. If RNA Polymerase bonds better and it opens up the strands fasted, more RNA will be made. That results in more proteins. A repressor protein will have the opposite effect, because it's the negative control and inhibits transcription.

     mRNA can make different proteins because there's different binding sites. When lactose is absent in E. coli, no b-galactosidase, lactose permease, and galactoside transavetylase is made because they only wanna make it when lactose is present. they're off in the default state, and only turn on when lactose is available.

     Now, we'll talk about regulation of transcription in eukaryotes. Some of the same principles are present as the ones in prokaryotes, such as activator and repressor proteins influence ability of RNA polymerase to initiate transcription, and many are regulated by small effector molecular. However, unlike prokaryotes, their genes are almost always organized individually, which makes the regulation more intricate. This is why we have different types of cells in our body, but the genomes are the same.

B.  Useful Materials

Video: Cell Differentiation

http://www.teachersdomain.org/resource/tdc02.sci.life.stru.different/

     This video shows a fertilized egg developing into an embryo, a fetus, and eventually a fully formed organism (in this case, it's a baby chick). It shows how the cells keep on dividing. Then, cells start to develop into different, unique types of cells. They start forming a spinal cord, and then eventually form the other organs. All the different cells have the same genome, but they have different functions. This process of cells changing into other cells is called cell differentiation. This is discussed in section 13.1.

Animation: Lac Repressor

http://www.sumanasinc.com/webcontent/animations/content/lacoperon.html

     The lac repressor is a protein that is expressed whether or not lactose is present, however, lactose's absence or presence changes its effect. When lactose is not present, the lac repressor binds to the lac operator site of the DNA. This prevents the RNA polymerase from continuing on, and thus prevents transcription, meaning no proteins will be made. When lactose is present, it binds to the lac repressor and changes its shape so it's no longer able to bind to the DNA. Transcription can now occur, and the proteins for metabolizing lactose are made. This is discussed in section 13.2.

Article: Chromatin and Alternative Splicing

http://www.ncbi.nlm.nih.gov/pubmed/21289049

     When it comes to humans, 90% of our genes are affected by alternative splicing. Alternative splicing is a form of gene regulation that allows an organism to use the same gene to make different proteins at different stages of development, in different cell types, and/or in response to a change in the environmental conditions. Changes in the chromatin could modulate splicing choices. A recent report shows that physiological stimulus can cause this, and in another report, it shows it can occur by creating specific histone modifications at targeted genes. Alternative splicing is discussed in section 13.4.