Chapter 20 - Biotechnology

Question 1

recombinant DNA

Answer 1

A DNA molecule made <em>in vitro</em> with segments from different sources.

Question 2

biotechnology

Answer 2

The manipulation of organisms or their components to produce useful products.

Question 3

genetic engineering

Answer 3

The direct manipulation of genes for practical purposes.

Question 4

plasmid

Answer 4

A small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chromosome; in DNA cloning, used as vectors carrying up to about 10,000 base pairs (10 kb) of DNA. Plasmids are also found in some eukaryotes, such as yeasts.

Question 5

gene cloning

Answer 5

The production of multiple copies of a gene.

Question 6

restriction enzyme

Answer 6

An endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites).

Question 7

restriction site

Answer 7

A specific sequence on a DNA strand that is recognized and cut by a restriction enzyme.

Question 8

restriction fragment

Answer 8

A DNA segment that results from the cutting of DNA by a restriction enzyme.

Question 9

sticky end

Answer 9

A single-stranded end of a double-stranded restriction fragment.

Question 10

DNA ligase

Answer 10

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).

Question 11

cloning vector

Answer 11

In genetic engineering, a DNA molecule that can carry foreign DNA into a host cell and replicate there. Cloning vectors include plasmids and bacterial artificial chromosomes (BACs), which move recombinant DNA from a test tube back into a cell, and viruses that transfer recombinant DNA by infection.

Question 12

genomic library

Answer 12

A set of cell clones containing all the DNA segments from a genome, each within a plasmid, BAC, or other cloning vector.

Question 13

bacterial artificial chromosome

Answer 13

A large plasmid that acts as a bacterial chromosome and can carry inserts of 100,000 to 300,000 base pairs (100-300 kb).

Question 14

complementary DNA (cDNA)

Answer 14

A double-stranded DNA molecule made <em>in vitro</em> using mRNA as a template and the enzymes reverse transcriptase and DNA polymerase. A cDNA molecule corresponds to the exons of a gene.

Question 15

cDNA library

Answer 15

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.

Question 16

nucleic acid hybridization

Answer 16

The process of base pairing between a gene and a complementary sequence on another nucleic acid molecule.

Question 17

nucleic acid probe

Answer 17

In DNA technology, a labeled single-stranded nucleic acid molecule used to located a specific nucleotide sequence in a nucleic acid sample. Molecules of the probe hydrogen-bond to the complementary sequence wherever it occurs; radioactive, fluorescent, or other labeling of the probe allows its location to be detected.

Question 18

expression vector

Answer 18

A cloning vector that contains a highly active 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. Expression vectors are also available that have been genetically engineered for use in specific types of eukaryotic cells.

Question 19

electroporation

Answer 19

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 cell’s plasma membranes, through which DNA can enter.

Question 20

polymerase chain reaction (PCR)

Answer 20

A technique for amplifying DNA <em>in vitro</em> by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides.

Question 21

gel electrophoresis

Answer 21

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 made of agarose or another polymer.

Question 22

restriction fragment length polymorphism (RFLP)

Answer 22

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.

Question 23

Southern blotting

Answer 23

A technique that enables specific nucleotide sequences to be detected in samples of DN A. It involves gel electrophoresis of DNA molecules and their transfer to a membrane (blotting), followed by nucleic acid hybridization with a labeled probe.

Question 24

Northern blotting

Answer 24

A technique that enables specific nucleotide sequences to be detected in samples 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.

Question 25

reverse transcriptase-polymerase chain reaction (RT-PCR)

Answer 25

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.

Question 26

<em>in situ</em> hybridization

Answer 26

A technique using nucleic acid hybridization with a labeled probe to detect the location of a specific mRNA in an intact organism.

Question 27

DNA microarray assay

Answer 27

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.

Question 28

<em>in vitro</em> mutagenesis

Answer 28

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.

Question 29

RNA interference (RNAi)

Answer 29

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.

Question 30

genome-wide association study

Answer 30

A large-scale analysis of the genomes of many people having a certain phenotype or disease , with the aim of finding genetic markers that correlate with that phenotype or disease.

Question 31

single nucleotide polymorphism (SNP)

Answer 31

A single base-pair site in a genome where nucleotide variation is found in at least 1% of the population.