Lab 7 Flashcards
what is biotechnology
it is the use of organisms or their components (e.g. DNA, proteins) to make or modify products useful to humans
what is modern biotechnology
it has been developed since the 1970s and specifically refers to the manipulation of DNA invitro
what does modern biotechnology permit
the alteration of specific DNA sequences as well as the transfer of genes between organisms which enabled revolutonary advances in the field of forensics, medicine, ag, polution control and evolutonary biology
what is the structure of DNA like
-large double stranded double helix
-each strand is composed of nucleotides
-each nucleotide is composed of 3 parts
-within each of the two strands of DNA nucloetides are joined by covalent phosphodiester bonds
-between the two strands of DNA, H bonds are formed between complementry N bases ( A+T C+G)
what is the 3 parts a nucletide is composed of
-nitrognous base
-sugar (deoxyribose)
-phosphate group which is - charged
what is the central dogma
-the flow of info from DNA to RNA
-info that is encoded in the DNA is transcribed into a complementry RNA copy. the RNA copy is translated into a sequence of amino acids which are the building blocks of proteins
what does forensic refer to
the use of scientific methods in a wide array of legal or investigation situations
what is forensic biology
it is an that area of science that deals with DNA from body tissues and fluids
what must biological samples collected for DNA contain
it must contain nucleated cells
what are suitable nucleated cells
bodily fluids (saliva, blood, semen, vaginal secrtrations, urine), hair folecles, skin, organs, bones
what are the most common types of biological samples obtained from
blood, hair, or buccal (cheek) cells
can all blood contain DNA
blood contains 4 components—RBC, WBC, plateletes, and plasma. in mammals mature RBC alone are not suitable for DNA extraction. they lack nuclei and organelles whereas WBC are nucleated
how is DNA extracted from the nuclei of the cells in a sample
extraction is accomplished by chemically lysing (breaking open) the cells and the nuclei to liberate the DNA which is then chemically precipitated out of solution
why are sports drinks used as a medium for collecting intact banana cells
because it is isotonic to the inside of the banana cell
when extracting DNA why do we add alcohol
DNA is highly soluble in water but insoluble in alcohol therefor DNA ppts out in solution into the ethanol layer
what is polymerased chain reaction
it is a process that rapidly makes identical copies of DNA sequences
why would you need to use polymerase chain reaction for an investigation
often only small biological samples are available to invesigators. much less required for investigations. the numerous copies of spicific DNA sequences can then be used in subsequent analysis
what DNA is the polymerase chain reaction usually used for
it is used to copy a particular DNA sequence of intrest (e.g a ene) for comparison, rather then the entire DNA complement
what are the 4 ingredience needed for polymerase chain reaction
-DNA extract
-each of the 4 deoxyribosenucleotide triphosphates (dNTPs: DATP, dCTP, dGTP, dTTP) these are the building blocks used to produce the copies of DNA
-primers—short segments of synthetic DNA necessary for the initiation of DNA replication
-DNA polymerase (taq polymerase) a heat soluble enzy,e that elonglates the DNA chain by adding dNTPs to the primers
-the ingredience are combined and the solution is placed in a thermal cycler, an automated system that maintains a series of temperatures for specified periods.
what are the 3 steps of a PCR cycle
-denaterization of DNA (heat to seperate the two strands of the DNA double helix)
-annealing of primers (cool so that primers can bond to the single strands of DNA
-extension of primers (heat allow DNA polymerase (Taq) to add dNTPs to the end of the primers
what is the result at the end of each PCR cycle
the DNA sequence specified by the primers in doubled in quantity which results in an exponental increase. therefore the end resule of numerous consecutive cycles is billions of identical copied of the same specific DNA sequence. this rapid selective amplification is complete within hours
what does restriction fragment analysis allow
it enables an indirect comparison of nucleotide sequences in different DNA samples through the use of restriction enzymes which “cut” DNA within different DNA within specific recognition sequences/restriction sites
what are restriction fragments
for eample restriction enzyme ecori recognizes and cuts DNA within the nitrogenous base sequence GAATTC. the resulting lengths of DNA are what is called restriction fragments
for restriction fragments what cant determine genetically different people
since alleles of genes very in their nucleotide sequences they may similarly very in the number of potential restriction sites contained within those sequences. differences in the number of restriction sites yield restriction fragments that differ both in number and the size in genetically different individuals
what is the first step used in restriction fragment analysis
it is a restriction digest
what is restriction digest processfor fragment analysis
a restriction enzyme is added to the PCR product and the solution is placed in an incubator. the enzyme cuts the DNA in the PCR product into specific fragment sizes and numbers, depending on the number of restriction sites present
what is the second step in restriction fragment analysis
gel electrophoresis
how does the gel electrophoresis procedure in restriction fragment analysis work
it is a process that allows is to separate the restriction fragments based upon molecular size differences in size of the DNA fragments
what is the gel electrophoresis in restriction fragment analysis made form
-agarose (a polysaccaride derived from algae)
-the gel is submerged in a chamber containing salt water which conducts electricity
what happens in gel electrophoresis once all the samples of DNA have been loaded. what are the mechanics
electrodes are attached to both ends of the chamber and a current is applied. the DNA which is - charged due to its phosphate backbone migrate towards the + electrode. the gel is a porous matrix which slows the movement of DNA fragments. larger DNA fragments cannot pass through the matrix of the gel as easily as smaller frangments so they do not travel as far
what are the odds of individuals having identical patters of restriction enzymes
between 1 and 100,000 and 1 in one billion
what is recombinant DNA
when DNA from two different sources (i.g two species) is combined into one molecule
what things has recombinant DNA been engineered to facilitate the manufacture of
-numerous of medically and agriculturally important proteins
-also been used to produce crops that are resistant to herbicides, pest and diseases
what is a genetically modified organism
an organsim that acquired genes through any artificial process, including recombinant DNA technology
