Selected sections of…. Ch 11 How Genes are Controlled Ch 12 DNA Technology and Genomics (how we contol genes!)

Gene Expression is controlled. …the kinds and amounts of proteins that are in a cell at any time. The cell coordinates the synthesizing, stockpiling, using, exporting and degrading thousands of types of proteins

Points of Protein Production Control: p 217 1 Points of Protein Production Control: p 217 1. Before Transcription (access to DNA) 2. Transcript Processing (post transcriptional modification) 3. Translation 4. After Translation (the polypeptide)

Proteins interacting with DNA turn prokaryotic genes on or off in response to environmental changes p 210 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. Student Misconceptions and Concerns 1. The broad concept of selective reading of the genetic code associated with differentiation and types of cellular activity can be missed when concentrating on the extensive details of regulation. Analogies, noted below in the teaching tips, can help students relate this overall selective process to their own experiences. Students already understand the selective reading of relevant chapters in textbooks and the selective referencing of software manuals to get answers to different questions. These experiences are similar in many ways to the broad processes of gene regulation. 2. The many levels of gene regulation in eukaryotic cells can be confusing and frustrating. The water pipe analogy depicted in Figure 11.7 can be a helpful reference to organize the potential sites of regulation. Teaching Tips 1. The lactose operon is turned on by removing the repressor . . . a sort of double negative. Students might enjoy various analogies to other situations, including the familiar refrain “When the cat's away, the mice will play.” Like a cat watching mice, if a mom keeps her kids away from cookies, but somebody occupies her attention, kids can sneak by and snatch some cookies. Thus, the person occupying Mom’s attention functions most like lactose binding to the repressor. 2. A key advantage of an operon system is the ability to turn off or on a set of genes with a single “switch.” You can demonstrate this relationship in your classroom by turning off or on a set of lights with a single switch. 3. The control of gene expression is analogous to buying a book about how to build birdhouses and reading only the plans needed to build one particular model. Although the book contains directions to build many different birdhouses, you read and follow only the directions for the particular birdhouse you choose to build. The pages and directions for the other birdhouses remain intact. When cells differentiate, they read, or express, only the genes that are needed in that particular cell type. © 2012 Pearson Education, Inc. 4

Operon turned off (lactose is absent): OPERON Regulatory gene Promoter Operator Lactose-utilization genes DNA mRNA RNA polymerase cannot attach to the promoter Protein Active repressor Operon turned on (lactose inactivates the repressor): Figure 11.1B The lac operon DNA RNA polymerase is bound to the promoter mRNA Translation Protein Inactive repressor Lactose Enzymes for lactose utilization 5

Lac Operon Animations http://www.youtube.com/watch?v=oBwtxdI1zvk http://www.youtube.com/watch?v=iPQZXMKZEfw http://www.phschool.com/science/biology_place/biocoach/lacoperon/intro.html

Complex assemblies of proteins control eukaryotic transcription Prokaryotes and eukaryotes employ regulatory proteins (activators and repressors) that bind to specific segments of DNA and either promote or block the binding of RNA polymerase, turning the transcription of genes on and off. Student Misconceptions and Concerns 1. The broad concept of selective reading of the genetic code associated with differentiation and types of cellular activity can be missed when concentrating on the extensive details of regulation. Analogies, noted below in the teaching tips, can help students relate this overall selective process to their own experiences. Students already understand the selective reading of relevant chapters in textbooks and the selective referencing of software manuals to get answers to different questions. These experiences are similar in many ways to the broad processes of gene regulation. 2. The many levels of gene regulation in eukaryotic cells can be confusing and frustrating. The water pipe analogy depicted in Figure 11.7 can be a helpful reference to organize the potential sites of regulation. Teaching Tips The authors note that the selective unpackaging of chromosomes is the “coarse adjustment” of eukaryotic gene expression. The initiation of RNA synthesis is the fine-tuning of the regulation. If you have recently asked your students to use microscopes in lab, you might relate these degrees of adjustment to the coarse and fine control knobs of a microscope. 7

DNA technologies: Understanding and Manipulating DNA Human Genome Project- mapping human genes Cloning Recombinant DNA DNA profiling (fingerprinting)

Human Genome Project 1990-2003 p 248 longest gene 37,122 bp, smallest gene 114 bp, average 3,000 bp Human Genome Project identified all 20,500 genes in human DNA, determine the sequences of the 3 billion chemical base pairs that make up human DNA http://web.ornl.gov/sci/techresources/Human_Genome/index.shtml

Cloning- embryo splitting Embryo splitting has been a routine part of research for decades

Cloning- SCNT

The thing about Dolly…. 1996 Dolly was born. First organism cloned from an adult (fully differentiated) cell. Cell was from sheep mammary gland.

What’s been cloned? In 1952, the first animal, a tadpole, was cloned. Before the creation of Dolly, the first mammal cloned from the cell of an adult animal, clones were created from embryonic cells. Since Dolly, researchers have cloned a number of large and small animals including sheep, goats, cows, mice, pigs, cats, rabbits, and a gaur. For more information on cloning…. http://www.ornl.gov/sci/techresources/Human_Genome/elsi/cloning.shtml

Restriction Enzymes: p 232-234 Naturally produced and found in bacteria Used to cut double stranded DNA at a specific base sequence (4-8 bps in length) ….. “SCISSORS”

The basic mechanism of DNA Recombinant Technology

Recombinant DNA: Animation Plasmid- small circle of DNA with only a few genes. Creating a plasmid with gene “of interest” http://www.dnai.org/text/mediashowcase/index2.html?id=549 Can act as a vector!

DNA fingerprinting/DNA profiling The basic procedure for creating a “picture” of DNA bands. http://www.pbs.org/wgbh/nova/sheppard/labwave.html

Gel Electrophoresis