PLoS Biology : Publishing science, accelerating research A Peer-Reviewed, Open Access Journal Current Issue PLOS Biology is a peer-reviewed, open-access journal featuring research articles of exceptional significance in all areas of biological science, from molecules to ecosystems. Lecture Notes October 24, 2013 Introduction We began by reviewing our introduction to levels of regulation in bacterial gene expression from last time. Cells can regulate transcription or translation, or regulate proteins post-translationally. The fastest response will be post-translational and the slowest will be transcriptional. We also reviewed the concepts of positive and negative regulation of transcription. There are examples of both positive and negative regulation of transcription in the lac operon. We reviewed the circuitry of the lac operon in response to three different states: abundant glucose but no lactose, both glucose and lactose, and lactose alone. As shown below, in the presence of abundant glucose but no lactose, cAMP levels will be low, so CAP protein will not bind to the lac operon to enhance transcription. As shown below, in the presence of abundant glucose and also lactose, cAMP levels will be low, so CAP protein will not bind to the lac operon to enhance transcription.
Microscope Imaging Station. Stem Cells: Cells with Potential. What are stem cells? Your body contains over 200 types of cells, each with a specific job: blood cells carry oxygen; muscle cells contract so that you can move; nerve cells transmit chemical signals. The job of a stem cell is to make new cells. It does this by undergoing an amazing process—differentiating, or changing into another type of cell. Each time a stem cell divides, one of the new cells might remain a stem cell while the other turns into a heart, blood, brain, or other type of cell. Stem cells are the source, or “stem,” for all of the specialized cells that form our organs and tissues. Next: Why invest so much in studying stem cells? Scientists observe single gene activity in living cells in detail for first time Researchers at Albert Einstein College of Medicine of Yeshiva University have for the first time observed the activity of a single gene in living cells. In an unprecedented study, published in the April 22 online edition of Science, Einstein scientists were able to follow, in real time, the process of gene transcription, which occurs when a gene converts its DNA information into molecules of messenger RNA (mRNA) that go on to make the protein coded by the gene. Robert Singer, Ph.D., co-director of the Gruss Lipper Biophotonics Center at Einstein and professor and co-chair of anatomy and structural biology, is senior author of the paper. The study's lead author is Daniel Larson, Ph.D., previously a member of Dr. Using florescent proteins, the researchers were able to follow mRNA activity by inserting DNA sequences into a gene in live yeast cells. This research was funded by the National Institutes of Health and the National Institute of General Medical Sciences.
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DAVID: Gene Functional Classification What does this tool do? Quickly translate given gene IDs to corresponding gene names in a batch way Provide links for each genes to DAVID Gene Report for in-depth information Search functionally related genes within user's input gene list or genome Key Concepts of "Search Related Genes" Any given gene is associating with a set of annotation terms. If genes share similar set of those terms (annotation profile), they are most likely involved in similar biological mechanisms. Find Related Genes Tool is very different and complementary to the common gene clustering methods, such as homologous genes based on sequence similarity; protein families based on one common biological activity.
MCAT Biology | Prokaryotic Cells Background Prokaryotic Cell Structure Prokaryotes are simple organisms that contain no membrane bound organelles. These simple organisms are commonly known as bacteria, viruses and bacteriophages. They may also contain plasmids, which is a small ring that contains a few genes that may offer antibacterial resistance. Prokaryotes also have 50s/30s subunit ribosomes and have locomotion through their flagella Prokaryotic Asexual Replication Simple prokaryotic cells such as bacteria and viruses replicate asexually which means that they do not require a partner to make an offspring. Binary Fission Budding Regeneration Parthenogenesis Binary Fission Binary fission is a rapid process of replication that occurs in prokaryotes. Binary fission is a little bit different than mitosis as the separate DNA regions attach to the cell membrane as the cells begin to stretch apart. Budding Budding is a type of replication that produces a daughter cell with an unequal division of cytoplasm. Regeneration Bacteria