How Genes Are Regulated

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Wireless CommunicationsWireless Wide Area Networks 2Objectives•Describe wireless wide area networks (WWANs) and how they are used•Describe the applications that can be used on a digital cellular telephone•Explain how cellular telephony functions•List features of the various generations of cellular telephony•Discuss how satellite transmissions work 3Cellular Telephone Applications•Digital cellular telephones can be used to:–Browse the Internet–Send and receive short messages and e-mails–Participate in videoconferencing–Receive various sorts of information–Run a variety of business applications–Connect to corporate networks–Watch television or on-demand movies–Take and transmit pictures and short movies–Locate family members and employees using GPS 4Cellular Telephone Applications (continued)•Short Message Services (SMS)–One of the most widely used applications–Allows for the delivery of short, text-based messages between wireless devices•Messages are limited to about 160 characters–Applications•Person-to-person•Agent-to-person•Information broadcast services•Software configuration•Advertising 5How Cellular Telephony Works•Keys to cellular telephone networks–Cells•City cells measure approximately 10 square miles•At the center of each cell is a cell transmitter connected to a base station•Each base station is connected to a mobile telecommunications switching office (MTSO)–Link between the cellular network and the wired telephone world–Controls all transmitters and base stations 6How Cellular Telephony Works (continued) 7How Cellular Telephony Works (continued)•Keys to cellular telephone networks (continued)–Transmitters and cell phones operate at low power•Enables the signal to stay confined to the cell•Signal at a specific frequency does not go far beyond the cell area–Same frequency can be used in other cells at the same time–Except in adjacent cells•Cell phones have special codes 8How Cellular Telephony Works (continued) 9How Cellular Telephony Works (continued)•When user moves within the same cell–Transmitter and base station for that cell handle all of the transmissions•As the user moves toward the next cell–A handoff process occurs•Roaming–User moves from one cellular network to another 10How Cellular Telephony Works (continued) [...]... 1xRTT • Operates on two 1.25 MHz -wide frequency channels • Supports 144 Kbps packet data transmission 2 Objectives • Describe wireless wide area networks (WWANs) and how they are used • Describe the applications that can be used on a digital cellular telephone • Explain how cellular telephony functions • List features of the various generations of cellular telephony • Discuss how satellite transmissions... 26 Satellite Broadband Wireless • Use of satellites for personal wireless communication is fairly recent • Satellite use falls into three broad categories – Satellites are used to acquire scientific data and perform research in space – Satellites look at Earth from space – Satellites include devices that are simply reflectors 22 Wireless Application Protocol (WAP How Genes Are Regulated How Genes Are Regulated Bởi: OpenStaxCollege For a cell to function properly, necessary proteins must be synthesized at the proper time All organisms and cells control or regulate the transcription and translation of their DNA into protein The process of turning on a gene to produce RNA and protein is called gene expression Whether in a simple unicellular organism or in a complex multicellular organism, each cell controls when and how its genes are expressed For this to occur, there must be a mechanism to control when a gene is expressed to make RNA and protein, how much of the protein is made, and when it is time to stop making that protein because it is no longer needed Cells in multicellular organisms are specialized; cells in different tissues look very different and perform different functions For example, a muscle cell is very different from a liver cell, which is very different from a skin cell These differences are a consequence of the expression of different sets of genes in each of these cells All cells have certain basic functions they must perform for themselves, such as converting the energy in sugar molecules into energy in ATP Each cell also has many genes that are not expressed, and expresses many that are not expressed by other cells, such that it can carry out its specialized functions In addition, cells will turn on or off certain genes at different times in response to changes in the environment or at different times during the development of the organism Unicellular organisms, both eukaryotic and prokaryotic, also turn on and off genes in response to the demands of their environment so that they can respond to special conditions The control of gene expression is extremely complex Malfunctions in this process are detrimental to the cell and can lead to the development of many diseases, including cancer Prokaryotic versus Eukaryotic Gene Expression To understand how gene expression is regulated, we must first understand how a gene becomes a functional protein in a cell The process occurs in both prokaryotic and eukaryotic cells, just in slightly different fashions Because prokaryotic organisms lack a cell nucleus, the processes of transcription and translation occur almost simultaneously When the protein is no longer needed, 1/6 How Genes Are Regulated transcription stops As a result, the primary method to control what type and how much protein is expressed in a prokaryotic cell is through the regulation of DNA transcription into RNA All the subsequent steps happen automatically When more protein is required, more transcription occurs Therefore, in prokaryotic cells, the control of gene expression is almost entirely at the transcriptional level The first example of such control was discovered using E coli in the 1950s and 1960s by French researchers and is called the lac operon The lac operon is a stretch of DNA with three adjacent genes that code for proteins that participate in the absorption and metabolism of lactose, a food source for E coli When lactose is not present in the bacterium’s environment, the lac genes are transcribed in small amounts When lactose is present, the genes are transcribed and the bacterium is able to use the lactose as a food source The operon also contains a promoter sequence to which the RNA polymerase binds to begin transcription; between the promoter and the three genes is a region called the operator When there is no lactose present, a protein known as a repressor binds to the operator and prevents RNA polymerase from binding to the promoter, except in rare cases Thus very little of the protein products of the three genes is made When lactose is present, an end product of lactose metabolism binds to the repressor protein and prevents it from binding to the operator This allows RNA polymerase to bind to the promoter and freely transcribe the three genes, allowing the organism to metabolize the lactose Eukaryotic cells, in contrast, have intracellular organelles and are much more complex Recall that in eukaryotic cells, the DNA is contained inside the cell’s nucleus and it is transcribed into mRNA there The newly synthesized mRNA is then transported out of the nucleus into the cytoplasm, where ribosomes translate the mRNA into protein The processes of transcription and translation are physically separated by the nuclear membrane; transcription occurs only within the nucleus, and translation only occurs outside the nucleus in the cytoplasm The regulation of gene expression can occur at all stages of the process ([link]) Regulation may occur when the DNA is uncoiled and loosened from nucleosomes to bind transcription factors (epigenetic level), when the RNA is transcribed (transcriptional level), when RNA is processed and exported to the cytoplasm after it is transcribed (post-transcriptional level), when the RNA is translated into protein (translational level), or after the protein has been made (post-translational level) 2/6 How ... Copyright 2011, Social Media Examiner 2 0 1 1 S O C I A L M E D I A M A R K E T I N G I N D U S T R Y R E P O R T How Marketers Are Using Social Media to Grow Their Businesses A P R I L 2 0 1 1 BY MICHAEL A. STELZNER Sponsored by 2011 Social Media Marketing SocialMediaExaminer.com Page 2 of 41 Industry Report © 2011 Social Media Examiner Letter from the author… Hello, fellow marketer; Social media has gone mainstream. And for businesses it represents an unprecedented marketing opportunity that transcends traditional middlemen and connects companies directly with customers. This is why nearly every business on the planet is exploring social media marketing initiatives. This is our third annual study. Two years ago, businesses were uncertain about social media. Now it's here to stay and companies are rapidly responding to new social media opportunities. This 41-page report contains insight into how marketers are currently using social media and their future plans. If you're in charge of marketing your business, you'll want to closely examine the following pages. My team turned over every rock, looking for the "not so obvious" findings among this data-rich content. We set out to uncover the "who, what, where, when and why" of social media marketing. More than 3300 of your fellow marketers provided the kind of insight you won't find elsewhere. I hope you enjoy it! If you find value here, please let your peers know about this report. You can find the original page for the report here: http://www.socialmediaexaminer.com/social-media-marketing-industry-report-2011/ All my best! Michael A. Stelzner Founder, SocialMediaExaminer.com Join the discussion on Facebook at http://www.facebook.com/smexaminer Copyright Statement: All content © 2011 by Social Media Examiner - Copyright holder is licensing this under the Creative Commons License, Attribution-Noncommercial-No Derivative Works 3.0 Unported, http://creativecommons.org/licenses/by-nc-nd/3.0/. (This means you can post this document on your site and share it freely with your friends, but not resell it or use as an incentive for action.) 2011 Social Media Marketing SocialMediaExaminer.com Page 3 of 41 Industry Report © 2011 Social Media Examiner Table of contents EXECUTIVE SUMMARY . 4 MAJOR FINDINGS 5 TOP 10 SOCIAL MEDIA QUESTIONS MARKETERS WANT ANSWERED 6 USE OF SOCIAL MEDIA MARKETING How semiconductors are made Minhhuan4_9@yahoo.com Outline  Part 1: Mask design creation  Part 2: Front end Processing  Part 3: Back end processing Design/mask creation  Circuit design  Photomask creation Logic Circuit Design / Layout Design  Based on the development plan, the IC's function and performance are first decided, and the logic circuit is designed. During logic circuit design, a logic circuit diagram is drawn to determine the electronic circuit required for the requested function. Once the logic circuit diagram is complete, simulations are performed multiple times to test the circuit’s operation. If there is no issue with the operation, the actual layout pattern for the devices and the interconnects is designed by computer-aided design(CAD), and a mask pattern is drawn. Logic Circuit Design / Layout Design Photomask Creation  After design of the logic circuit and the layout, a photomask is required to transcribe the design onto the wafer for use during front-end processing. The photomask is a copy of the circuit pattern, drawn on a glass plate coated with a metallic film. The glass plate lets light pass, but the metallic film does not. A state-of-the-art mask drawing system is used for the pattern exposure of the photomask. Due to increasingly high integration and miniaturization of the pattern, the size of the photomask is usually magnified four to ten times the actual size, depending on the irradiation equipment. Photomask creation [...]... films and metallic films using the resist pattern as a mask Etching with liquid chemicals is called "wet etching" and etching with gas is called "dry etching" The oxide films are etched with chemicals (HF acid), and the metallic films are etched with plasma Etching Photoresist Stripping  The photoresist remaining on the wafer surface is no longer necessary after etching is complete Ashing by oxygen plasma... Usually ion implantation today • But regions are still called diffusion N-diffusion, Cont’d  Strip off oxide to complete patterning step P-Diffusion • Similar set of steps form p+ diffusion regions for pMOS source and drain and substrate contact Contacts Now we need to wire together the devices • Cover chip with thick field oxide • Etch oxide where contact cuts are needed Metallization - Sputter on aluminum... the "design / mask creation" step is placed over the photoresist-coated wafer, which is then irradiated to have the circuit diagram transcribed(sao chép) onto it The positions of the wafer and the mask are adjusted, and then an irradiation device called the "stepper" is used to irradiate the wafer through the mask with ultraviolet (UV) light Where unmasked, the wafer is exposed to the UV light, and the... patterning, the wafer is placed in a hightemperature furnace to make the silicon react with oxygen or water vapor, and to develop oxide films on the wafer surface (thermal oxidation) These oxide films are used for the insulation of transistor gates and for the insulation of interconnect layers To develop nitride films and polysilicon films, the chemical vapor deposition (CVD) method is used, in which... performed to remove the residual photoresist The wafer is also rinsed with an acidic solution to remove any impurities, such as metals and organic matters The steps from deposition to photoresist stripping are repeated multiple times to form a complex circuit pattern on the wafer Photoresist Stripping n-Well • n-well formed with diffusion or ion implant • Diffusion – Place wafer in furnace with arsenic... until As atoms diffuse into exposed Si • Ion Implantation – Blast wafer with beam of As ions – Ions blocked by SiO2, only enter exposed Si Strip Oxide Strip off the remaining oxide using HF • Back to bare wafer with n-well • Subsequent steps involve similar series of steps Polysilicon       Deposit very thin layer of gate What are snoRNAs? e biosynthesis of eukaryote ribosomes is complex, involving numerous processing events to generate mature ribosomal RNAs (rRNAs) and the subsequent assembly of processed rRNAs with dozens of ribosomal proteins. Small nucleolar RNAs (snoRNAs) are central to ribosome maturation, being required in key cleavage steps to generate individual rRNAs, and in their capacity as guides for site-specific modification of rRNA. In the rRNA of the budding yeast Saccharomyces cerevisiae, on the order of 100 snoRNA-guided modifications are made during the biosynthesis of a single ribosome; this number is approximately double in humans. Around half of these modifications are methylations of the 2’ position on ribose, and are carried out by C/D-box small nucleolar ribo nucleoproteins (snoRNPs), which consist of a guide snoRNA acting in concert with several proteins, includ- ing Nop1p, the RNA methylase component of the snoRNP. e remaining modifications produce pseudo- uridine, an isomer of uridine, and are guided by H/ACA- box snoRNPs, with the Cbf5p subunit performing the pseudouridylation reaction [1]. Figure 1 illustrates the inter action between the two types of snoRNA and their respective RNA targets. Over the past decade, the snoRNA universe has expanded rapidly. H/ACA- and C/D-family RNAs have been discovered in Archaea (where they are dubbed sRNAs, as Archaea lack nucleoli), and likewise modify rRNA, and in the Cajal body of the eukaryote cell (small Cajal body scaRNPs), where they modify small nuclear RNAs (snRNAs), the RNA constituents of the spliceo- some [2]. Recently, HBII-52, a human C/D snoRNA, has been shown to regulate splicing of serotonin receptor 2C mRNA, indicating a wider role in gene regulation [3], and another C/D snoRNA has been shown to be expressed from the Epstein-Barr virus genome [4]. As our know- ledge of snoRNAs expands beyond RNA modification and hints at wider regulatory roles, there is a need to identify the full repertoire of snoRNAs in a genome and establish when and on what RNAs they act. Against this backdrop, experimental screens that trawl organism-by- organism for snoRNAs are vital, as bioinformatic screens have so far failed to provide a robust computational alternative to labour-intensive experimental methods of RNA identification. Two recent papers in BMC Genomics by Zhang et al. [5] and Liu et al. [6] report the identi fic- ation of novel snoRNAs from the rhesus monkey Macaca mulatta and the filamentous fungus Neurospora crassa, respectively. Both sets of authors experimentally investi- gated snoRNA pools by sequencing cDNAs derived from RNA extracted from their species of interest. Subsequent bioinformatics analysis was used by each group to classify sequences as either of the two snoRNA classes or other- wise. ese approaches netted 48 H/ACA and 32 C/D box snoRNAs in the monkey and 20 H/ACA and 45 C/D box snoRNAs in the fungus. Studies like these are vital to the extension of our knowledge of how complements of snoRNAs vary through evolution. Given the intense effort required for such analyses, it is worth taking stock and asking, where are the current gaps in our knowledge of snoRNAs? The taxonomic distribution of known snoRNAs To investigate the taxonomic distribution of the known snoRNAs and highlight where potential new discoveries can be made, we have gathered data from the Pfam (protein families), Rfam (RNA families), Genomes Online (GOLD) and EMBL databases (Figure 2). e Rfam database uses experimentally validated ncRNA sequences that have been deposited in EMBL to search for homologous sequences across all nucleotide sequences (see the red and pink bars in Figure2). e results show Abstract Small nucleolar RNAs (snoRNAs) are among the most evolutionarily ancient classes of small RNA. Two experimental screens published in BMC Genomics expand the eukaryotic snoRNA catalog, but many more snoRNAs remain to be found. © Chapter 11 How Genes Are Controlled PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey © 2012 Pearson Education, Inc Lecture by Edward J Zalisko Introduction  Cloning is the creation of an individual by asexual reproduction  The ability to clone an animal from a single cell demonstrates that every adult body cell – contains a complete genome that is – capable of directing the production of all the cell types in an organism © 2012 Pearson Education, Inc Introduction  Cloning has been attempted to save endangered species  However, cloning – does not increase genetic diversity and – may trivialize the tragedy of extinction and detract from efforts to preserve natural habitats © 2012 Pearson Education, Inc Figure 11.0_1 Chapter 11: Big Ideas Control of Gene Expression The Genetic Basis of Cancer Cloning of Plants and Animals CONTROL OF GENE EXPRESSION © 2012 Pearson Education, Inc 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes  Gene regulation is the turning on and off of genes  Gene expression is the overall process of information flow from genes to proteins  The control of gene expression allows cells to produce specific kinds of proteins when and where they are needed  Our earlier understanding of gene control came from the study of E coli © 2012 Pearson Education, Inc Figure 11.1A E coli 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes  A cluster of genes with related functions, along with the control sequences, is called an operon  With few exceptions, operons only exist in prokaryotes © 2012 Pearson Education, Inc 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes  When an E coli encounters lactose, all the enzymes needed for its metabolism are made at once using the lactose operon  The lactose (lac) operon includes three adjacent lactose-utilization genes, a promoter sequence where RNA polymerase binds and initiates transcription of all three lactose genes, and an operator sequence where a repressor can bind and block RNA polymerase action © 2012 Pearson Education, Inc 11.1 Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes  Regulation of the lac operon – A regulatory gene, located outside the operon, codes for a repressor protein – In the absence of lactose, the repressor binds to the operator and prevents RNA polymerase action – Lactose inactivates the repressor, so – the operator is unblocked, – RNA polymerase can bind to the promoter, and – all three genes of the operon are transcribed © 2012 Pearson Education, Inc Figure 11.16A Proto-oncogene (for a protein that stimulates cell division) DNA A mutation within the gene Multiple copies of the gene Oncogene Hyperactive growthstimulating protein in a normal amount The gene is moved to a new DNA locus, under new controls New promoter Normal growthstimulating protein in excess Normal growthstimulating protein in excess Figure 11.16B Tumor-suppressor gene Normal growthinhibiting protein Cell division under control Mutated tumor-suppressor gene Defective, nonfunctioning protein Cell division not under control 11.17 Multiple genetic changes underlie the development of cancer  Usually four or more somatic mutations are required to produce a full-fledged cancer cell  One possible scenario is the stepwise development of colorectal cancer An oncogene arises or is activated, resulting in increased cell division in apparently normal cells in the colon lining Additional DNA mutations cause the growth of a small benign tumor (polyp) in the colon wall Additional mutations lead to a malignant tumor with the potential to metastasize © 2012 Pearson Education, Inc Figure 11.17A An oncogene A tumor-suppressor DNA changes: is activated gene is inactivated A second tumorsuppressor gene is ... eukaryotes; according to one estimate, 70% of genes in humans are expressed as multiple proteins through alternative splicing 4/6 How Genes Are Regulated There are five basic modes of alternative splicing... level), or after the protein has been made (post-translational level) 2/6 How Genes Are Regulated Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in.. .How Genes Are Regulated transcription stops As a result, the primary method to control what type and how much protein is expressed in a prokaryotic