Chapter 9 Power Notes Answer Key - Weebly

Chapter 9 Power Notes Answer Key

Section 9.1

Collected from--bacteria Used for--cutting DNA Cut DNA at--specific nucleotide sequences (restriction sites) Can leave--blunt ends (straight cuts) or sticky ends (staggered cuts with free nucleotides) 1. Restriction sites Gel electrophoresis--separates DNA fragments based on size; smaller fragments travel farther in a certain amount of time than larger fragments Restriction maps--fragment sizes between restriction sites; do not show anything about genes or DNA sequence

Section 9.2

PCR--technique that quickly copies a desired segment of DNA 1. temperature increased to separate DNA 2. temperature lowered and primers bind to each strand, bracketing the desired segment of DNA 3. temperature increased; polymerases make new strands of DNA PCR amplifies--every cycle doubles the number of strands of DNA

Section 9.3

DNA fingerprinting Based on--noncoding regions of DNA; number of nucleotide repeats in particular parts of the genome; a person's molecular identity; a type of restriction map using gel electrophoresis Person B--fragments at 2, 3, 4, 5 DNA fingerprints and probability--by investigating several parts of the genome, it is very unlikely that two people would randomly share identical numbers of repeats (multiplying each separate probability to find the total probability of a match) Uses--criminal cases; immigration; paternity; studying biodiversity; identifying species; tracking GM crops

Section 9.4

Cloning in nature--binary fission, some plants; some simple animals Mammals--nuclear transfer; low success rate; Dolly the sheep first clone of adult mammal Potential and controversy --could be used in medical treatments; save endangered species; bring back extinct species; low success rate; decrease biodiversity Genetic engineering--changing an organism's DNA to give the organism new traits Recombinant DNA--DNA with genes from more than one organism; genes often inserted into bacterial plasmids Transgenic bacteria--have plasmid with recombinant DNA; used to make human insulin Transgenic plants--bacteria with recombinant DNA infect plants; used to make crops

resistant to disease, insects, frost Transgenic animals--gene must be inserted in fertilized egg; used for medical research and to study gene expression Concerns--long-term effects of GM crops on human health, biodiversity; possible unintended consequences

Section 9.5

Gene sequencing--determining the sequence of a gene or an entire genome Genomics--study of entire genomes; can include sequencing of entire genome; compare genomes within and across species to find similarities and differences among different organisms Human Genome Project -- sequenced entire human genome; still working on identifying all genes, finding their locations, and determining their functions Bioinformatics--using computer databases to organize and analyze the vast amounts of data that result from studies of genetics (and other biological information) DNA microarrays--allow scientists to study the expression of many genes at one time; used to compare gene expression in different types of cells Proteomics--study and comparison of proteins within and across species; used to study evolutionary relationships and human diseases

Section 9.6

Genetic screening--the process of testing DNA to determine a person's risk of having or passing on a genetic disorder; can involve pedigree analysis Detecting disorders--tests can detect genes that produce disorders such as cystic fibrosis Detecting disease risk--tests for genes related to an increased risk of cancer, heart disease, etc. Gene therapy--replacement of defective or missing gene, or adding a new gene, to treat a disease Methods used Viruses--genes can be inserted into viruses that are used to infect a person's cells; the desired gene is inserted into the cells by the virus Immune system--genes inserted to stimulate a person's immune system to recognize and attack cancer cells Suicide gene--gene inserted into cancer cells that will activate a chemical to kill the cells; normal cells without the gene are not affected Technical challenges--inserting the gene into the correct cells; controlling gene expression; determining whether the new gene affects the expression of other genes

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