Chat with AIExam 15: Genomics
What are the advantages and disadvantages to using gene chip or microarray technology to study gene expression? How are microarrays created and used? What can be done to overcome the disadvantages of this technology?
(32) 
VerifiedNew technologies now allow scientists to produce microarrays that contain thousands of hybridization probes on a single membrane or other solid support.
Microarrays of oligonucleotide or cDNA probes are produced in several ways: (1)microsynthesis of oligonucleotides in situ (on the chip),(2)spotting prefabricated oligonucleotide probes on solid supports,and (3)spotting DNA fragments or cDNAs on the supports.The probes on the microarrays are then hybridized to labeled (usually with a fluorescent tag)RNA or cDNA samples.The amount of RNA or cDNA hybridized to each probe in a microarray is quantified by using sophisticated scanners with micrometer resolution and appropriate computer software.As knowledge in the field has advanced,geneticists have been able to study the expression of more and more genes.Now,for the first time,they can study the expression of all the genes of an organism simultaneously.The ability to analyze the expression of entire genomes will enhance the current explosion of new information in biology and will eventually lead to an understanding of the normal process of human development and the causes of at least some human diseases.Array hybridizations and gene chips can be used to determine whether genes are transcribed,but they provide no information about the translation of the gene transcripts.Thus,biologists often use antibodies to detect the protein products of genes of interest.Western blots are used to detect proteins separated by electrophoresis,and antibodies coupled to fluorescent compounds are used to detect the location of proteins in vivo.However,both of these approaches provide only a single time-point assay of a protein in a cell,tissue,or organism.The discovery of a naturally occurring fluorescent protein,the green fluorescent protein (GFP)of the jellyfish Aequorea victoria,has provided a powerful tool that can be used to study gene expression at the protein level.GFP is now being used to monitor the synthesis and localization of specific proteins in a wide variety of living cells.These studies entail constructing fusion genes that contain the nucleotide sequence encoding GFP,coupled in frame to the nucleotide sequence encoding the protein of interest; introducing the chimeric gene into cells by transformation; and studying the fluorescence of the fusion protein in transgenic cells exposed to blue or UV light.Because GFP is a small protein,it can often be coupled to proteins without interfering with their activity or interaction with other cellular components.
Which of the following is not true regarding mtDNA?
(39) VerifiedC
Which of the following is a disadvantage of using gene chips to study gene expression?
1)Gene chips cannot provide information on whether a sequence has been transcribed
2)Gene chips cannot provide information on whether a sequence has been translated
3)Gene chips hold sequences for entire genomes so it makes it harder to study individual sequences
(39) VerifiedB
Markers that have been mapped both physically and genetically on a chromosome are known as:
(39) Which of the following could be a future application of the technology,skills,and data acquired from the Human Genome Project?
1)Individuals can have their DNA sequenced
2)Researchers can determine genetic variations among different populations of humans
3)Drugs can be developed based upon an individuals genetic makeup
(40) Why was it necessary to use radiation hybrid mapping to help construct a map of the human genome,and how is radiation hybrid mapping conducted?
(37) The science of gathering,manipulating,storing,retrieving,and classifying recorded biological information is known as:
(40) Which of the following is a method for correlating a physical map of a chromosome with a genetic map and/or a cytological map?
1)Genes that have been cloned can be positioned on the cytological map by in situ hybridization
2)Locating clones of genetically mapped genes or RFLPs on the physical map
3)Using PCR to amplify short unique genomic DNA sequences and Southern blots to relate these sequences to overlapping clones on physical maps
(34) If a molecular marker such as a restriction fragment-length polymorphism (RFLP)maps close to a gene,the gene can usually be isolated by which of the following?
(34) Variations in the lengths of DNA fragments produced by restriction enzyme digestion are known as:
(38) How does the technique of chromosome walking compare with the technique of chromosome jumping?
(37) Which of the following is true for the procedures of both chromosome walking and chromosome jumping?
1)It is initiated by using a molecular probe such as an RFLP as a starting point
2)DNA fragments are prepared by partial digestion with a restriction enzyme
3)Genomic fragments are circularized using DNA Ligase
(34) Which of the following criteria would allow a researcher to perform chromosome walking in an organism? 1.Small genome size
2)A small amount of dispersed repetitive DNA
3)A large amount of dispersed repetitive DNA
(36) Which of the following is used to construct a genetic map of a chromosome?
1)Recombination frequencies
2)Banding patterns of chromosomes
3)Molecular distances separating sites on a DNA fragment
(34) Based on the sequencing data acquired from the Human Genome Project,how many genes are in the human genome?
(32) Which of the following proteins is being used to monitor the synthesis and localization of proteins in vivo?
(38) Short unique anchor sequences that correlate physical,genetic,and cytological maps of chromosomes are known as:
(34) Which of the following is a type of RFLP,particularly useful for mapping in humans,that is not based upon the cleavage pattern of a particular restriction enzyme but on the difference of the number of copies of a repeated sequence between restriction sites?
(31) 
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