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Unformatted text preview: BIO 1140 SLIDE #1 Unit 2 Information flow Unit 2 What explains the variety of systems and their regulation? DNA RNA Protein The Central Dogma Replication Transcription Translation Reading Chapter 13.3,13.4 Chapter 14 Chapter 15 Objectives DNA Replication in eucaryotes What is a gene? Transcription in eucaryotes Translation in eucaryotes Regulation BIO 1140 SLIDE #2 BIO1140 CELL BIOLOGY Examples of netiquette rules concerning peer respect (from Centre for University Teaching) Be sure your device sound is set to off at the beginning of class Stay on task. Activities such as Web surfing or gaming may distract classmates. Listen to your classmates if they complain to you that your use is distracting BIO 1140 SLIDE #3 Unit 2 Information flow Gene Regulation WHY IS UNDERSTANDING REGULATION THE KEY TO UNDERSTANDING SO MUCH OF LIFE? Changes in environment or changes in nutrients Changes in make up of cell is response to signals In a multicellular organism, cellular differentiation Conserve energy Gene regulation refers to the regulation of activity and may occur at any level. While the main control is at the level of transcription additional controls are at the posttranscriptional, translational and posttranslational levels. At the level of transcription, trans-acting factors Interacting with cis-acting sequences.- tells us how everything is integrated- all of these involve cis acting sequences and trans- if you don't produce the right proteins, or if you don't produce enough... etc in trouble - which is why regulation is important - must be able to respond to changes in enviro or nutrients and respond adequately BIO 1140 SLIDE #4 Regulation of Gene Expression in Prokaryotes Start with a simple, but powerful model. Prokaryotic gene expression reflects life history. In many cases rapid, reversible responses to the environment are observed. Typically RNA polymerase binds to a DNA sequence 5 to the gene called the promoter . Within the promoter may be the consensus sequence 5'-TATAAT-3' called a TATA box . Repressor proteins binding to other regulatory DNA sequences may prevent the gene from being expressed. Activator proteins binding to other regulatory DNA sequences may turn on expression of the gene. Repressors and activators may regulate the same gene. Unit 2 Information flow BIO 1140 SLIDE #5 Unit 2 Information flow In prokaryotes many genes are organized into clusters ( transcription units ) that are implicated in a single function. At a smaller scale many genes are organized into operons (one or more operons may be found within a transcription unit ) The operon itself can be considered as a unit of transcription with several genes controlled by a single promoter . In effect an operon is a cluster of genes and DNA sequences involved in their regulation. RNA polymerase binds at the promoter and transcribes all the genes in the operon into one mRNA (called...
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