Biology Chapter 9 & Honors Biology Chapter 13 Frontiers Of .

Biology Chapter 9 &Honors Biology Chapter 13FrontiersOfBiotechnology

DNA TECHNOLOGY IS ABOUT: Manipulating DNA for man’s purposes.– It includes: cutting DNA, Gel Electrophoresis andPolymerase Chain ReactionsScientists use several techniquesto manipulate DNA.

DNA TECHNIQUE #1: Cutting DNAHow do you “cut DNA?Restriction enzymes cut DNA at a specific nucleotidesequence called a restriction site. Restriction enzymes act as “molecular scissors.”– come from various types of bacteria– allow scientists to more easily study and manipulategenes

Different restriction enzymes cut DNA in differentways.– each enzyme has a different restriction site– DNA chemical bonds are broken in the “cutting”

– some cut straight across and leave “blunt ends”– some make staggered cuts and leave “sticky ends” have overhanging nucleotides

9.1 Manipulating DNA Restriction Enzyme Activity http://www.classzone.com/cz/books/bio 07/get chapter group.htm?cin 3&ci 9&rg animated biology&at animated biology&npos 2&spos 9&var animated biology

DNA TECHNIQUE #2: Gel Electrophoresis Gel electrophoresis is used to separate DNAfragments by size.– A DNA sample is cut with restriction enzymes.– Uses Electrical current to pull DNA fragmentsthrough a gel.

– Smaller fragments travel faster and travel fartherthan longer, larger fragments.– Fragments of differentsizes appear asbands on the gel.

A restriction map shows the lengths of DNA fragmentsbetween restriction sites.– only indicate size,not DNA sequence– useful in geneticengineering– used to studymutations

9.1 Manipulating DNAKEY CONCEPTDNA fingerprints identify people at the molecularlevel.

9.1 Manipulating DNAA DNA fingerprint is a type of restriction map. DNA fingerprints are based on parts of an individual’sDNA that can by used for identification.– based on noncoding regions of DNA– noncoding regions have repeating DNA sequences– number of repeats differs between people– banding pattern on a gel (from gel electrophoresis isa DNA fingerprint

9.1 Manipulating DNA

9.1 Manipulating DNADNA fingerprinting is used for identification. DNA fingerprinting depends on the probability of amatch.(mother) (child 1) (child 2) (father)– Many people have thesame number ofrepeats in a certainregion of DNA.– The probability that twopeople share identicalnumbers of repeats inseveral locations isvery small.

9.1 Manipulating DNA– Individual probabilities are multiplied to find theoverall probability of two DNA fingerprints randomlymatching.11111 chance in 5.4 million people500 x 90 x 120 5,400,000 – Several regions of DNA areused to make DNA fingerprints.

9.1 Manipulating DNA DNA fingerprinting is used in several ways.– evidence in criminalcases– paternity tests– immigration requests– studying biodiversity– tracking geneticallymodified crops–Ex. Tortoise species areidentified with DNAfingerprinting to determinewhich Galapagos Island theycame from, so raised tortoisesmay be reintroduced to theirNative islands to increasetheir numbers. (San Diego Zoo)

KEY CONCEPTThe polymerase chain reaction (PCR) rapidlycopies segments of DNA.

PCR uses polymerases to copy DNA segments. PCR makes many copies of a specific DNA sequence in afew hours.target sequence of DNA PCR amplifies DNA samples. PCR is similar to DNA replication.

PCR is a three-step process. PCR uses four materials.– DNA to be copied– DNA polymerase– A, T, C, and G nucleotides– two primers short strandsDNA strandsof DNA tobuild the newpolymerasestrands on,act like“bookends” nucleotidesprimer 1primer 2

9.1 Manipulating DNAPCR animation http://www.classzone.com/cz/books/bio 07/get chaptergroup.htm?cin 3&ci 9&rg animated biology&at animated biology&npos 2&spos 9&var animated biology

The three steps of PCR occur in a cycle.– heat is used to separate double-stranded DNAmolecules– primers bind to each DNA strand on opposite ends ofthe segment to be copied– DNA polymerase binds nucleotides together to formnew strands of DNADNA strandsprimer 1polymerasenucleotidesprimer 2

Each PCR cycle doubles the number of DNA molecules.

Biology Chapter 9 & Honors Biology Chapter 13 Frontiers Of Biotechnology. DNA TECHNOLOGY IS ABOUT: Manipulating DNA for man’s purposes. –It includes: cutting DNA, Gel Electrophoresis and Polymerase Chain Reactions Scientists use several techniques . McDougal Littell Created Date: