Adapted from:
Urry, L., Cain, M., Wasserman, S., Minorsky, P., Jackson, R., & Reece, J. (2014). Campbell biology in focus. Boston: Pearson Education, Inc. (ISBN# 0321813804)
Terms : Hide Images
| 787519823 | Bacterial artificial chromosome | A large plasmid that acts as a bacterial chromosome and can carry inserts of 100,000 to 300,000 base pairs. | |
| 787519824 | Bacteriophage | A virus that infects bacteria; also called a phage. | |
| 787519825 | Biotechnology | The manipulation of organisms or their components to produce useful products. | |
| 787519826 | cDNA library | A gene library containing clones that carry complementary DNA (cDNA) inserts. The library includes only the genes that were transcribed in the cells whose mRNA was isolated to make the cDNA. | |
| 787519827 | Cloning vector | In genetic engineering, a DNA molecule that can carry foreign DNA into a host cell and replicate there. Cloning vectors include plasmids that move recombinant DNA from a test tube back into a cell and viruses that transfer recombinant DNA by infection. | |
| 787519828 | Complementary DNA (cDNA) | A double-stranded DNA molecule made in vitro using mRNA as a template and the enzymes reverse transcriptase and DNA polymerase. A cDNA molecule corresponds to the exons of a gene. | |
| 787519829 | DNA ligase | A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3´ end of one DNA fragment (such as an Okazaki fragment) to the 5´ end of another DNA fragment (such as a growing DNA chain). | |
| 787519830 | DNA microarray assay | A method to detect and measure the expression of thousands of genes at one time. Tiny amounts of a large number of single-stranded DNA fragments representing different genes are fixed to a glass slide and tested for hybridization with samples of labeled cDNA. | |
| 787519831 | DNA polymerase | An enzyme that catalyzes the elongation of new DNA (for example, at a replication fork) by the addition of nucleotides to the 3´ end of an existing chain. There are several different DNA polymerases; DNA polymerase III and DNA polymerase I play major roles in DNA replication in prokaryotes. | |
| 787519832 | Double helix | The form of native DNA, referring to its two adjacent antiparallel polynucleotide strands wound around an imaginary axis into a spiral shape. | |
| 787519833 | Electroporation | A technique to introduce recombinant DNA into cells by applying a brief electrical pulse to a solution containing the cells. The pulse creates temporary holes in the cells' plasma membranes, through which DNA can enter. | |
| 787519834 | Euchromatin | The less condensed form of eukaryotic chromatin that is available for transcription. | |
| 787519835 | Expression vector | A cloning vector that contains the requisite bacterial promoter just upstream of a restriction site where a eukaryotic gene can be inserted, allowing the gene to be expressed in a bacterial cell. | |
| 787519836 | Gel electrophoresis | A technique for separating nucleic acids or proteins on the basis of their size and electrical charge, both of which affect their rate of movement through an electric field in a gel. | |
| 787519837 | Gene cloning | The production of multiple copies of a gene. | |
| 787519838 | Gene therapy | The introduction of genes into an afflicted individual for therapeutic purposes. | |
| 787519839 | Genetic engineering | The direct manipulation of genes for practical purposes. | |
| 787519840 | Genetic profile | An individual's unique set of genetic markers, detected most often today by PCR or, previously, by electrophoresis and nucleic acid probes. | |
| 787519841 | Genetically modified (GM) organism | An organism that has acquired one or more genes by artificial means; also known as a transgenic organism. | |
| 787519842 | Genomic library | A set of cell clones containing all the DNA segments from a genome, each within a plasmid, phage, or other cloning vector. | |
| 787519843 | Helicase | An enzyme that untwists the double helix of DNA at the replication forks, separating the two strands and making them available as template strands. | |
| 787519844 | Heterochromatin | Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed. | |
| 787519845 | Histone | A small protein with a high proportion of positively charged amino acids that binds to the negatively charged DNA and plays a key role in chromatin structure. | |
| 787519846 | In situ hybridization | A technique used to detect the location of a specific mRNA using nucleic acid hybridization with a labeled probe in an intact organism. | |
| 787519847 | In vitro mutagenesis | A technique used to discover the function of a gene by cloning it, introducing specific changes into the cloned gene's sequence, reinserting the mutated gene into a cell, and studying the phenotype of the mutant. | |
| 787519848 | Lagging strand | A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5´→3´ direction away from the replication fork. | |
| 787519849 | Leading strand | The new complementary DNA strand synthesized continuously along the template strand toward the replication fork in the mandatory 5´→3´ direction. | |
| 787519850 | Mismatch repair | The cellular process that uses specific enzymes to remove and replace incorrectly paired nucleotides. | |
| 787519851 | Northern blotting | A technique that enables specific nucleotide sequences to be detected in a sample of mRNA. It involves gel electrophoresis of RNA molecules and their transfer to a membrane (blotting), followed by nucleic acid hybridization with a labeled probe. | |
| 787519852 | Nuclease | An enzyme that cuts DNA or RNA, either removing one or a few bases or hydrolyzing the DNA or RNA completely into its component nucleotides. | |
| 787519853 | Nucleic acid hybridization | The process of base pairing between a gene and a complementary sequence on another nucleic acid molecule. | |
| 787519854 | Nucleic acid probe | In DNA technology, a labeled single-stranded nucleic acid molecule used to locate a specific nucleotide sequence in a nucleic acid sample. Molecules of the probe hydrogen-bond to the complementary sequence wherever it occurs; radioactive or other labeling of the probe allows its location to be detected. | |
| 787519855 | Nucleoid | A dense region of DNA in a prokaryotic cell. | |
| 787519856 | Nucleosome | The basic, bead-like unit of DNA packing in eukaryotes, consisting of a segment of DNA wound around a protein core composed of two copies of each of four types of histone. | |
| 787519857 | Nucleotide excision repair | A repair system that removes and then correctly replaces a damaged segment of DNA using the undamaged strand as a guide. | |
| 787519858 | Okazaki fragment | A short segment of DNA synthesized away from the replication fork on a template strand during DNA replication, many of which are joined together to make up the lagging strand of newly synthesized DNA. | |
| 787519859 | Origin of replication | Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. | |
| 787519860 | Phage | A virus that infects bacteria; also called a bacteriophage. | |
| 787519861 | Plasmid | A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome. Plasmids are also found in some eukaryotes, such as yeasts. | |
| 787519862 | Pluripotent | Describing a cell that can give rise to many, but not all, parts of an organism. | |
| 787519863 | Polymerase chain reaction (PCR) | A technique for amplifying DNA in vitro by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides. | |
| 787519864 | Primase | An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template. | |
| 787519865 | Primer | A short stretch of RNA with a free 3´ end, bound by complementary base pairing to the template strand, that is elongated with DNA nucleotides during DNA replication. | |
| 787519866 | Recombinant DNA | A DNA molecule made in vitro with segments from different sources. | |
| 787519867 | Replication fork | A Y-shaped region on a replicating DNA molecule where the parental strands are being unwound and new strands are growing. | |
| 787519868 | Restriction fragment | A DNA segment that results from the cutting of DNA by a restriction enzyme. | |
| 787519869 | Restriction fragment length polymorphism (RFLP) | A single nucleotide polymorphism (SNP) that exists in the restriction site for a particular enzyme, thus making the site unrecognizable by that enzyme and changing the lengths of the restriction fragments formed by digestion with that enzyme. A RFLP can be in coding or noncoding DNA. | |
| 787519870 | Restriction site | A specific sequence on a DNA strand that is recognized and cut by a restriction enzyme. | |
| 787519871 | Reverse transcriptase-polymerase chain reaction (RT-PCR) | A technique for determining expression of a particular gene. It uses reverse transcriptase and DNA polymerase to synthesize cDNA from all the mRNA in a sample and then subjects the cDNA to PCR amplification using primers specific for the gene of interest. | |
| 787519872 | RNA interference (RNAi) | A technique used to silence the expression of selected genes. RNAi uses synthetic double-stranded RNA molecules that match the sequence of a particular gene to trigger the breakdown of the gene's messenger RNA. | |
| 787519873 | Semiconservative model | Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand. | |
| 787519874 | Short tandem repeats (STR) | Simple sequence DNA containing multiple tandemly repeated units of two to five nucleotides. Variations in STRs act as genetic markers in STR analysis, used to prepare genetic profiles. | |
| 787519875 | Single nucleotide polymorphism (SNP) | A single base-pair site in a genome where nucleotide variation is found in at least 1% of the population. | |
| 787519876 | Southern blotting | A technique that enables specific nucleotide sequences to be detected in a sample of DNA. It involves gel electrophoresis of DNA molecules and their transfer to a membrane (blotting), followed by nucleic acid hybridization with a labeled probe. | |
| 787519877 | Stem cell | Any relatively unspecialized cell that can produce, during a single division, one identical daughter cell and one more specialized daughter cell that can undergo further differentiation. | |
| 787519878 | Sticky end | A single-stranded end of a double-stranded restriction fragment. | |
| 787519879 | Telomerase | An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells. | |
| 787519880 | Telomere | The tandemly repetitive DNA at the end of a eukaryotic chromosome's DNA molecule that protects the organism's genes from being eroded during successive rounds of replication. | |
| 787519881 | Ti plasmid | A plasmid of a tumor-inducing bacterium (the plant pathogen Agrobacterium) that integrates a segment of its DNA (T DNA) into a chromosome of a host plant. The Ti plasmid is frequently used as a vector for genetic engineering in plants. | |
| 787519882 | Topoisomerase | A protein that breaks, swivels, and rejoins DNA strands. During DNA replication, topoisomerase helps to relieve strain in the double helix ahead of the replication fork. | |
| 787519883 | Totipotent | Describing a cell that can give rise to all parts of the embryo and adult, as well as extraembryonic membranes in species that have them. | |
| 787519884 | Transformation | (1) The conversion of a normal animal cell to a cancerous cell. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. | |
| 787519885 | Transgenic | Pertaining to an organism whose genome contains a gene introduced from another organism of the same or a different species. | |
| 787519886 | Yeast artificial chromosome | A cloning vector that combines the essentials of a eukaryotic chromosome—an origin for DNA replication, a centromere, and two telomeres—with foreign DNA. |
