Chapter 20: DNA tools and Biotech – Flashcards
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Biotechnology is ...
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the manipulation of organisms or their components to make useful products
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DNA technology affects:
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agriculture criminal law medical research research of anything in biology
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Nucleic acid hybridization
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the base pairing of one strand of nucleic acid to the complementary sequence of another strand
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Genetic engineering is...
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the direct manipulation of genes for practical purposes
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DNA sequencing...
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Complementary base pairing allow researchers to determine a gene's complete nucleotide sequence
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Next-generation sequencing
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techniques use a single template strand that is immobilized and amplified to produce an enormous number of identical fragments
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transcriptome is
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mRNA
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Steps to Sequencing: 1-3
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1- Genomic DNA is fragmented 2- Each fragment is isolated witha bead. 3- Using PCR, 106 copies of eachfragment are made, each attachedto the bead by 5′ end
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Steps to Sequencing: 4-6
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4- The bead is placed into a well withDNA polymerases and primers. 5- A solution of each of the four nucleotidesis added to all wells and then washed off.The entire process is then repeated. 6- If a nucleotide is joined to a growing strand, PPi is released, causing a flash of light that is recorded.
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Steps to Sequencing: 7&8
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7- If a nucleotide is notcomplementary to thenext template base,no PPi is released, andno flash of light is recorded. 8- The process is repeated until everyfragment has a complete complementarystrand. The pattern of flashes reveals thesequence.
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DNA cloning is when scientists prepare...
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well-defined DNA segments in multiple identical copies
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Plasmids are...
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small circular DNA molecules that replicate separately from the bacterial chromosome
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Researchers can insert ___ into ________ to produce recombinant DNA, a molecule with DNA from two different sources
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DNA; plasmids
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Steps to producing recombinant DNA:
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1- gene inserted into plasmid 2- plasmid put into bacterial cell 3- host cell grown in culture to form a clone of cells containing the "cloned" gene of interest 4- Basic research and various applications
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Bacterial restriction enzymes
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cut DNA molecules at restriction sites
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Restriction sites
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where DNA is cut at specific DNA sequences
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Restriction fragments are produced from the many cuts made by ________ __________.
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restriction enzyme
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The most useful restriction enzymes cut DNAin a staggered way, producing fragments with "_____ ___"
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sticky ends
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Sticky ends can bond with _______sticky ends of other fragments.
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complementary
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DNA ligase is
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an enzyme that seals the bonds between restriction fragments
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polymerase chain reaction aka:
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PCR
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PCR ...
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can produce many copies of a specific target segment of DNA
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PCR has a...
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three-step cycle
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The 3 step cycle of PCR consists of:
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heating, cooling, and replication
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PCR is used in
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cloning, studies of gene expression, DNA sequencing and more!
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PCR primers can be designed to
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include restriction sites that allow the product to be cloned into plasmid vectors
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Expression vector have 5 characteristics:
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Ability to replicate Recognition sequence A strong promoter A selectable marker gene Small size
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The process that uses nucleic acid probes to study gene expression in intact organisms is called __________.
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in situ hybridization
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What is a "pharm" animal?
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a transgenic organism that expresses a foreign gene that was added to the zygote
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Which of the following enzymes is key to the automation of PCR (polymerase chain reactions)?
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Taq polymerase
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A nucleic acid probe is used to __________.
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identify genes that have been inserted into bacterial plasmids or separated by electrophoresis
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One method for cloning organisms is nuclear transplantation. What happens in this process?
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The nucleus of an unfertilized egg is removed and replaced with the nucleus of a differentiated cell.
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What enzyme is used to bind DNA fragments with sticky ends that have hydrogen bonded to each other?
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DNA ligase
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The term "STR" stands for __________.
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short tandem repeat
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Reverse transcriptase produces __________ from an RNA template.
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cDNA
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A pluripotent embryonic stem cell __________.
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can differentiate into many different cell types
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In Gurdon's work with nuclear transplantation in frogs, which of the following characteristics of donor cells affected the extent to which the donor cell nuclei could support normal development in the egg cells that received the donor nuclei?
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The older the donor nuclei, the lower the percentage of normally developing tadpoles
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When a typical restriction enzyme cuts a DNA molecule, the cuts are staggered so that the DNA fragments have single-stranded ends. This is important in recombinant DNA work because __________.
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the fragments will bond to other fragments with complementary single-stranded ends
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In the PCR process, once the identified segment of DNA is heated to separate the strands, what substances are then added to facilitate the copying of the segment?
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primers, nucleotides, and polymerase
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Bacteria use restriction enzymes to __________.
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destroy foreign DNA
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In recombinant methods, the term vector refers to __________.
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a plasmid or other agent used to transfer DNA into a living cell
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The efficiency of cloning, and the ability to generate healthy cloned animals, has been largely hampered by the difficulty of __________.
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completely reversing epigenetic alterations in donor cell nuclei such as DNA methylation and chromatin packing
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What do DNA microarray assays allow scientists to study regarding gene expression?
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These assays allow scientists to identify networks of gene expression across an entire genome.
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Therapeutic cloning refers to __________.
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the use of cloned embryos as a source of stem cells that could be used to treat disease
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Which of the following enzymes could seal a nick in one strand of a double-stranded DNA molecule by creating a sugar-phosphate bond between the adjacent, unjoined nucleotides?
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DNA ligase
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Because eukaryotic genes contain introns, they cannot be translated by bacteria, which lack RNA-splicing machinery. But if you want to engineer a bacterium to produce a eukaryotic protein, you can synthesize a gene without introns. A good way to do this is to __________.
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work backward from mRNA to make a version of the gene without introns
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In the polymerase chain reaction (PCR), the sequence of bases in the primers is important because it __________.
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determines which segment of the genome will be amplified
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What is the source of the reverse transcriptase used in recombinant DNA technology?
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Retroviruses
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In the polymerase chain reaction (PCR) technique, a heating phase and a cooling phase alternate. An original sample of DNA would have to pass through how many total rounds of heating and cooling before a sample is increased eight times in quantity?
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Three
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DNA fingerprints used as evidence in a murder trial look something like supermarket bar codes. The pattern of bars in a DNA fingerprint shows __________.
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the presence of various-sized fragments of DNA
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Which of the following statements best describes the process of in vitro mutagenesis?
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Specific mutations are introduced into a cloned gene, and the mutated gene is returned to the cell in such a way that it disables ("knocks out") the normal cellular copies of the same gene.
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The expression of the PAX-6 gene when vertebrate and fruit fly versions of the gene are exchanged between these animal groups illustrates __________.
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the common ancestry in the evolution of these animal groups
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__________ can give rise to any type of cell whereas __________ can give rise to a subset of cell types.
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Embryonic stem cells; adult stem cells
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Which of the following statements best describes gene therapy?
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Gene therapy adds functioning versions of a defective gene to somatic cells.
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Which of the following describe(s) concerns regarding genetically modified (GM) organisms used as food?
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They may cause allergic reactions in humans. They may pose various environmental risks. Genes for pesticide resistance in lawn and crop grasses may be transferred to wild plants, producing "super weeds." They may pose various health risks in humans.
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How does the process of dideoxyribonucleotide chain termination sequencing determine the base-pair sequence in a piece of DNA?
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One strand of a DNA fragment is used as a template for synthesis of a nested set of complementary fragments; these are further analyzed to yield the sequence.
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Where in a DNA strand do restriction enzymes cut the strand?
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At symmetrical sequences of bases
