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88 Cards in this Set
- Front
- Back
A good transition state analog binds to the enzyme ______.
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more tightly than the substrate
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The benefit of measuring the initial rate of a reaction (Vo) is that ___.
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at the beginning of the reaction changes in [S] are negligible, so [S] can be treated as a constant
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The role of an enzyme in an enzyme-catalyzed reaction is to ____.
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increase the rate at which substrate is converted into product
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How is trypsinogen converted to trypsin?
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Proteolysis of trypsinogen forms trypsin
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To calculate the turnover number of an enzyme, you need to know____.
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the enzyme concentration and the initial velocity of the catalyzed reaction at S >> Km
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Enzymes are potent catalysts because they _____.
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lower the activation energy for the reactions they catalyze
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Penicillin related durgs inhibit the enzyme ______; this enzyme is produced by _____.
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transpeptidase; bacteria
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Can increase the reaction rate for a given reaction by a thousand-fold or more
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enzyme catalyst
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Used to solve graphically for the rate of an enzymatic reaction at infinite substrate concentration
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Lineweaver-Burk
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A small molecule that decreases the activity of an enzyme by binding to a site other than the catalytic site is termed an _______.
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allosteric inhibitor
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The concept of ____________ refers to the fact that substrate binding may induce a conformational change in the enzyme, which then brings catalytic groups into proper orientation.
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induced fit
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Name the six internationally accepted classes of enzymes
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Oxidoreductases, Lyases, Transferases, Hydrolases, Isomerases, Ligases
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One of the enzymes involved in glycolysis, aldolase, requires Zn for catalysis. Under conditions of zinc deficiency, when the enzyme may lack zinc, it would be referred to as the _____.
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apoenzyme
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In a plot of 1/V against 1/[S] for an enzyme catalysed reaction, the presence of a competitive inhibitor will ______.
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alter the intercept on the 1/S axis.
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Enzymes differ from other catalyst in that _____.
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Only enzymes display specificity toward a single reactant
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Carbon Monoxide (CO) is toxic to humans because _____
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it binds to the Fe in hemoglobin and prevents the binding of oxygen.
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In hemoglobin the transition from T to R state (low to high affinity) is triggered by _____.
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oxygen binding
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A non correct fact about 2,3 bisphosphoglycerate is that ___
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it increases the affinity of hemoglobin for oxygen
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The amino acid substitution of Val for Glu in hemoglobin S results in aggregation of the protein because of ______.
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hydrophobic interactions between molecules.
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The interactions of ligands with proteins are usually ____.
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transient
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Myoglobin and the subunits of hemoglobin have very similar ______ but very different ______.
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tertiary structures; primary structures
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An allosteric interaction between a ligand and a protein is one in which ______.
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binding of a molecule to a binding site affects binding properties of another site on the protein.
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In the binding of oxygen to myoglobin the relationship between the concentration of oxygen and the fraction of binding sites occupied can best be described as ______.
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hyperbolic
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The predominant structural feature in myosin molecules is an ____.
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alpha helix
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A monoclonal antibody differs from a polyclonal antibody in that _____.
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monoclonal antibodies are synthesized by a population of identical or cloned cells.
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Amino acid residues commonly found in the middle of Beta turn are _____.
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Pro and Gly.
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Which of the following is least likely to result in protein denaturing?
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changing salt concentration
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To alter Alpha keratin chains shape you first reduce, then you _______.
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shape remodeling and then chemical oxidation
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In an aqueous solution, protein conformation is determined by two major factors: _______.
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maximum number of hydrogen bonds and placement of hydrophobic amino acid residues within the interior of the protein.
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Proteins often have regions that show specific, coherent patterns of folding or function. These regions are called:
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domains
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Determining the precise arrangement of atoms within a large protein is possible only through the use of _____.
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xray diffraction
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In an alpha helix, the R groups on the amino acid residues are found_____.
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on the outside of the helix spiral
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Roughly how many amino acids are there in one turn of an alpha helix?
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3.6
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A non weak interaction in proteins is _____.
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peptide bonds
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Protein S will fold into its native conformation only when protein Q is also present. However Q can fold into its native conformation without protein S. Protein Q therefore may function as a _____ for protein S.
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molecular chaperone
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The information carrying intermediates of translation
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mRNA
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Scientist who noted the A:T and G:C ratios in DNA are pproximately 1:1.
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Erwin Chargroff
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the temperature at which double stranded DNA separates into separate strands
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the melting temperature
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DNA renaturation after melting is called
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annealing
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Organisms in which the flow of genetic information can be RNA > DNA
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retroviruses
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Codons that specify the same amino acids are termed
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synonyms
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a three-base codon defines a specific
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amino acid
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stop codons are read by
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release factors
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DNA is more resistant to base-catalyzed hyrdolysis than RNA. What feature of DNA is responsible for this characteristic?
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The absence of a 2'-hydroxyl group in deoxyribose
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How does a nucleotide differ from a nucleoside?
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A nucleotide is a nucleoside with a phosphate ester linked to the sugar
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What is the nucleotide sequence (5'>3') on the DNA template strand that yields the 5' > 3' CUA codon for leucine?
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TAG
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The technique used by Franklin and Wilkins to deduce the structure of DNA was
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Xray diffraction
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The feature of DNA deduced by Watson and Crick included:
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two antiparalled polynucleotide chains coiled in a helix around a common axis, the pyrimidine and purine bases lie on the inside of the helix, the bases are nearly perpendicular to the axis
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What are the common promoter regions found in bacterial genes?
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A Pribnow box about -10 and a -35 region
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Features of the genetic code include
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the code is degenerate and a codon is defined by three bases
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The first amino acid in bacterial proteins is
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fMet
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In which codon position do most synonyms differ?
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third position
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Arber, Smith, and Nathans discovered and pioneered the use of
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restriction enzymes
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A pattern of DNA fragments can serve as a _____ of a particular DNA molecule.
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genetic fingerprint
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the most common type of DNA sequencing is
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Sanger dideoxy nucleotide method
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Instead of radioactivity, current DNA sequencing commonly uses ____ base analogues.
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fluorescent
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The first genome to be sequenced of a free-living organism
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Haemophilus influenza
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Won the Nobel prize for discovery of the polymerase chain reaction.
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Kary Mullis
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A plasmid is an example of a common ____.
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vector
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the enzyme used to create DNA from RNA is
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reverse transcriptase
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The enzyme that catalyzes the formation of a phosphodiester linkage at a break in DNA strand
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DNA ligase
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cleaves DNA at sites with inverted repeat sequences referred to as palendromic sequences
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restriction endonucleases
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Complementary, single-strand overhangs that are produced by some restriction endonucleases are referred to as
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sticky ends or cohesive ends
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The Sanger technique for sequencing DNA involves the use of ___ nucleotide analogs that terminate chain elongation.
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2',3' dideoxy
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DNA fragments can be visualized in polyacrylamide gel electrophoresis by staining with ____ which binds to double stranded DAN and fluoresces an intense orange when irradiated by UV light.
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ethidium bromide
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The viological role of restriction enzymes in bacteria is to
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cleave foreign DNA
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Which of the following DNA sequences contains a 48 base palindromic site?
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GCATATGC
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Plasmids used in recombinant DNA technology typically
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posses a gene for antibiotic resistance, replicate independently of the host genome, are circular double stranded molecules
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A polylinker site contains
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many closely spaced restriction enzyme sites
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Reverse transcriptase is normally found in
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retroviruses
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Foreign genes can be inserted into eukaryotic cells by
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viruses, liposomes, chemical treatment, and microinjections
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Animals that harbor a foreign gene as a result of recombinant gene manipulation are called
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transgenic
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techniques for engineering new proteins by site-directed gene mutations include:
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oligonucleotide directed mutagenesis and cassette mutagenesis
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The temperature at which half the DNA helical character is lost is referred to as
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Tm
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The difference in RNA bases compared to DNA bases is
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RNA contains U instead of T
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What are two primary components of a gene?
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exons and introns
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Why are deletion and insertion mutations usually lethal?
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changes the reading frame
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What is an advantage of codon degeneracy?
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it lessens the chance of deleterious mutations
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A plasmid vector that contains the beta-galactosidase gene and is useful for screening cells with recombined DNA
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pUC18
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How can DNA fragments of various sizes be separated?
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gel electrophoresis
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A labeled complementary single stranded DNA used in things such as southern blotting
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DNA probe
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What is the basis of the Sanger method for DNA sequencing?
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DNA can be sequenced by controlled termination of replication using 2',3'-dideoxy nucleotide analogs
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Explain the the basis of the polymerase chain reaction
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To analyze and amplify specific DNA sequences using 3 steps: 1) strand separation 2) hybridization of primers 3) DNA synthesis
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Briefly outline the steps necessary to create a recombinant DNA molecule
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1) Cleave with restriction enzymes
2) Anneal DNA fragments and join with DNA ligase |
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How is a single gene of interest identified on a plate containing many different library clones?
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screening a genomic library for a specific gene
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How is gene disruption used to determine the function of a gene?
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uses process of homologous recombination
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How is a gene gun used?
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most effective way of transforming plant cells DNA is coated onto tungsten pellets and they are fired at the target cells with very high velocities
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Briefly outline how a cDNA library is made
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complementary DNA for all mRNA that a cell contains can be made, inserted into vectors, and then inserted into bacteria
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