Gene regulation and expression Big Q: How are prokaryotic genes regulated? Big Q: How are genes regulated in eukaryotic cells? Big Q: What controls the development of cells and tissues in multicellular organisms?
Engage - Gene Regulation Why are cells so different from one another in structure and function? Nerve cells have dendrites and axons and are specialized to transmit information. Red blood cells have no nuclei and are packed with hemoglobin. If the characteristics of a cell depend upon the proteins that are synthesized, what does this tell you about protein synthesis? Work with a partner to discuss and answer the questions that follow. . 1. Do you think that cells produce all of the proteins for which the DNA (genes) code? Why or why not? How do the proteins made affect the type and function of cells? . 2. Consider what you may know about genes and protein synthesis. What might be some ways that a cell has control over the proteins it produces?
Explain - Prokaryotic Gene Regulation Gene regulation is controlled by the presence or absence of proteins. Transcription is driven by the presence of the protein. Jacob and Monod discovered lactose transcription in E.Coli bacteria.
Elaborate - The Lac Operon The Lac Operon Model Contains: 1. Operon - group of genes that are regulated together 2. Operator - Lac repressor enzyme can bind here 3. Promotor - binding site for RNA polymerase
Elaborate - Turn On or Off One Gene One Polypeptide Theory - one gene directs the synthesis of a specific protein Repressor blocks transcription Lactose turns operator on
Explain - Eukaryotic Gene Regulation Most genes are controlled individually. 1. TATA region - spot where RNA polymerase attaches based on the 25-30 base pair TATA region 2. Transcription Factors - help facilitate transcription by attracting RNA polymerase, relaxing chromatin, or blocking genes 3. Introns - loops of extra RNA that are cut out. They do not code for amino acids 4. Exons - code of amino acids to become a protein
Explain - Eukaryotic Gene Regulation
Explore - RNA Interference Look at the picture and describe what you think is happening.
Elaborate - The Discovery of RNA Interference Analyze the data in the given chart ***Answers questions on your worksheet
Explain - Homeotic Genes Homeotic Genes - master genes that regulate organ development in specific parts of the body Homeobox Genes - code for information to activate genes used in differentiation Hox Genes - determine segmentation
Elaborate - Hox Genes Watch the video about Hox genes and explain how this process is important to developing body segments in organisms.
Evaluate - Gene regulation Complete your exit ticket before you leave