AP Bio Midterm Key Terms Ch. 20

Question 1

bacterial artificial chromosome (BAC)

Answer 1

An artificial version of a bacterial chromosome that can carry inserts of 100, 000 to 500, 000 base pairs.

Question 2

biotechnology

Answer 2

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

Question 3

cDNA library

Answer 3

A limited gene library using complementary DNA. The library includes only the genes that were transcribed in the cells examined.

Question 4

clone

Answer 4

(1) A lineage of genetically identical individuals or cells. (2) In popular usage, a single individual organism that is genetically identical to another individual. (3) As a verb, to make one or more genetic replicas of an individual or cell.

Question 5

cloning vector

Answer 5

An agent used to transfer DNA in genetic engineering. A plasmid that moves recombinant DNA from a test tube back into a cell is an example of a cloning vector, as is a virus that transfers recombinant DNA by infection.

Question 6

complementary DNA (cDNA)

Answer 6

A DNA molecule made in vitro using mRNA as a template and the enzyme reverse transcriptase. A cDNA molecule therefore corresponds to a gene, but lacks the introns present in the DNA of the genome.

Question 7

denaturation

Answer 7

In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix. Denaturation occurs under extreme conditions of pH, salt concentration, and temperature.

Question 8

DNA fingerprint

Answer 8

An individual’s unique collection of DNA restriction fragments, detected by electrophoresis and nucleic acid probes.

Question 9

DNA ligase

Answer 9

A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of a new DNA fragment to the 5’ end of a growing chain.

Question 10

DNA microarray assay

Answer 10

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. These fragments, ideally representing all the genes of an organism, are tested for hybridization with various samples of cDNA molecules.

Question 11

electroporation

Answer 11

A technique to introduce recombinant DNA into cells by applying a brief electrical pulse to a solution containing cells. The electricity creates temporary holes in the cells’ plasma membranes, through which DNA can enter.

Question 12

expression vector

Answer 12

A cloning vector that contains the requisite prokaryotic promoter just upstream of a restriction site where a eukaryotic gene can be inserted.

Question 13

gel electrophoresis

Answer 13

The separation of nucleic acids or proteins, on the basis of their size and electrical charge, by measuring their rate of movement through an electrical field in a gel.

Question 14

gene cloning

Answer 14

The production of multiple copies of a gene.

Question 15

gene therapy

Answer 15

The alteration of the genes of a person afflicted with a genetic disease.

Question 16

genetic engineering

Answer 16

The direct manipulation of genes for practical purposes.

Question 17

genetically modified (GM) organism

Answer 17

An organism that has acquired one or more genes by artificial means; also known as a transgenic organism.

Question 18

genomic library

Answer 18

A set of thousands of DNA segments from a genome, each carried by a plasmid, phage, or other cloning vector.

Question 19

genomics

Answer 19

The study of whole sets of genes and their interactions.

Question 20

Human Genome Project

Answer 20

An international collaborative effort to map and sequence the DNA of the entire human genome.

Question 21

in vitro mutagenesis

Answer 21

A technique to discover the function of a gene by introducing specific changes into the sequence of a cloned gene, reinserting the mutated gene into a cell, and studying the phenotype of the mutant.

Question 22

linkage map

Answer 22

A genetic map based on the frequencies of recombination between markers during crossing over of homologous chromosomes.

Question 23

nucleic acid hybridization

Answer 23

Base pairing between a gene and a complementary sequence on another nucleic acid molecule.

Question 24

nucleic acid probe

Answer 24

In DNA technology, a labeled single-stranded nucleic acid molecule used to tag 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.

Question 25

physical map

Answer 25

A genetic map in which the actual physical distances between genes or other genetic markers are expressed, usually as the number of base pairs along the DNA.

Question 26

polymerase chain reaction (PCR)

Answer 26

A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides.

Question 27

proteomics

Answer 27

The systematic study of the full protein sets (proteomes) encoded by genomes.

Question 28

recombinant DNA

Answer 28

A DNA molecule made in vitro with segments from different sources.

Question 29

restriction enzyme

Answer 29

A degradative enzyme that recognizes and cuts up DNA (including that of certain phages) that is foreign to a bacterium.

Question 30

restriction fragment

Answer 30

DNA segment resulting from cutting of DNA by a restriction enzyme.

Question 31

restriction fragment length polymorphisms (RFLPs)

Answer 31

Differences in DNA sequence on homologous chromosomes that can result in different patterns of restriction fragment lengths (DNA segments resulting from treatment with restriction enzymes); useful as genetic markers for making linkage maps.

Question 32

restriction site

Answer 32

A specific sequence on a DNA strand that is recognized as a cut siteby a restriction enzyme.

Question 33

RNA interference (RNAi)

Answer 33

A technique to silence the expression of selected genes in non mammalian organisms. The method uses synthetic double-stranded RNA molecules matching the sequence of a particular gene to trigger the breakdown of the gene’s messenger RNA.

Question 34

single nucleotide polymorphisms (SNPs)

Answer 34

One base-pair variation of the genomic sequence.

Question 35

Southern blotting

Answer 35

A hybridization technique that enables researchers to determine the presence of certain nucleotide sequences in a sample of DNA.

Question 36

sticky end

Answer 36

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

Question 37

Ti plasmid

Answer 37

A plasmid of a tumor-inducing bacterium that integrates a segment of its DNA into the host chromosome of a plant; frequently used as a carrier for genetic engineering in plants.

Question 38

yeast artificial chromosome (YAC)

Answer 38

A vector that combines the essentials of a eukaryotic chromosome–an origin for DNA replication, a centromere, and two telomeres–with foreign DNA.