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Romm Rachel Biology 1H Ms. Mackley 10 February 2009 Focus Questions 1. Imagine you are trying to explain the difference between chromosomes, genes, and DNA to your younger brother or sister who is two years younger than you. Write down your explanation in simple words that they could understand. DNA is a code found in every cell in our body that contains instructions on how to be you. Your DNA is made up of many genes. Each gene tells you if you have blue eyes, black hair Your DNA is organized into 46 different chromosomes. Chromosomes are just curled up DNA. You have 46 chromosomes of DNA that contains about 40,000 genes. 2. Does a liver cell contain the same chromosomes as a cheek cell? Yes, liver cells and cheek cells contain the same chromosomes. 3. If you wanted to isolate a copy of a gene that codes for a protein found in the stomach, could that gene be located in cheek cells? Explain your reasoning. Yes, the copy of the gene that codes for a protein found in the stomach could be located in the cheek cell because all cells, except germ cells, contain the same DNA, therefore the same genes. 4. Label the cellular compartments, including the cell membrane, cytoplasm, and nucleus. 5. In which cellular compartment do you expect to find you genomic DNA? In the nucleus. 6. Why is an intermediate like mRNA needed to copy the information from the genomic DNA so it can be translated into protein? DNA is too big to go through the pores in the nuclear membrane. Therefore, mRNA is needed to copy just a single gene from the DNA and translate it into a protein. 7. What do you think will be the first step in isolating DNA from your cells? After obtaining the cells, the cell nuclear and membranes needs to be broken in order for the DNA to be free. 8. Once the membranes have been dissolved, the DNA is released into the solution, but so are many other types of cellular molecules. List some types of molecules besides DNA that you would expect to find a cell. - Water - Carbon - Glucose -Mitochondria - Oxygen dioxide - RNA -Phospholipids 9. What method or agent do you think might be used to break down these unwanted molecules? An enzyme might be used to break down unwanted molecules. 10. What proteins do you think would be associated with DNA in the cell? Some proteins that can be associated with DNA in the cell are histones and enzymes related to DNA replication. 11. The protease used in this procedure functions best at 50C. Would you expect this enzyme to be isolated from E. coli bacteria? Explain your answer. Hint: Where does E. coli live? This enzyme cannot be used to isolate DNA from E. coli bacteria because E. coli cant sustain temperatures of 50C. 12. Meat tenderizer is often used to tenderize tough pieces of meat, like steak. Knowing that steak is made of protein-rich muscle tissue from cows, can you think of an explanation for how meat tenderizer works? Meat tenderizer contains an enzyme or some chemical that denatures the proteins in the meat. 13. Match the outcomes on the left with the laboratory steps on the right. A. Harvest the cells gently chew the inside of your mouth and then rinse vigorously with water C. Dissolve cell membrane- mix in a detergent solution D. Precipitate the DNA layer cold alcohol over cell extract B. Break down protein - add protease, incubate at 50C E. Make the DNA less soluble in water add salt ... View Full Document

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