AP Biology Vocabulary & Roots: Ch. 20
1. bacterial artificial chromosome (BAC)-A large plasmid that acts as a bacterial chromosome
and can carry inserts of 100,000 to 300,000 base pairs.
2. biofuel-A fuel produced from dry organic matter or combustible oils produced by plants.
3. biotechnology-The manipulation of organisms or their components to produce useful products.
4. 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.
5. clone-(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. See also gene cloning.
6. 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.
7. 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.
8. DNA ligase-(li´-gas) 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).
9. 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.
10. 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.
11. 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.
12. gel electrophoresis-(e-lek´-tro-for-e´-sis) 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.
13. gene cloning-The production of multiple copies of a gene.
14. gene therapy-The introduction of genes into an afflicted individual for therapeutic purposes.
15. genetic engineering-The direct manipulation of genes for practical purposes.
16. genetic profile-An individual’s unique set of genetic markers, detected most often today by
PCR or, previously, by electrophoresis and nucleic acid probes.
17. genetically modified (GM) organism-An organism that has acquired one or more genes by
artificial means; also known as a transgenic organism.
18. genomic library-A set of cell clones containing all the DNA segments from a genome, each
within a plasmid, phage, or other cloning vector.
19. Huntington’s disease-A human genetic disease caused by a dominant allele; characterized by
uncontrollable body movements and degeneration of the nervous system; usually fatal 10 to 20
years after the onset of symptoms.
20. 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.
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21. 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.
22. 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.
23. nucleic acid hybridization-The process of base pairing between a gene and a complementary
sequence on another nucleic acid molecule.
24. 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 hydrogenbond to the complementary sequence wherever it occurs; radioactive or other labeling of the probe
allows its location to be detected.
25. Parkinson’s disease-A progressive brain disease characterized by difficulty in initiating
movements, slowness of movement, and rigidity.
26. plasmid-(plaz´-mid) 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.
27. pluripotent-Describing a cell that can give rise to many, but not all, parts of an organism.
28. polymerase chain reaction (PCR)-(puh-lim´-uh-ras) A technique for amplifying DNA in vitro
by incubating it with specific primers, a heat-resistant DNA polymerase, and nucleotides.
29. recombinant DNA-A DNA molecule made in vitro with segments from different sources.
30. restriction fragment-A DNA segment that results from the cutting of DNA by a restriction
enzyme.
31. 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.
32. restriction site-A specific sequence on a DNA strand that is recognized and cut by a restriction
enzyme.
33. 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.
34. 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.
35. short tandem repeat (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.
36. sickle cell disease - A human genetic disease caused by a recessive allele that results in the
substitution of a single amino acid in a globin polypeptide that is part of the hemoglobin protein;
characterized by deformed red blood cells (due to protein aggregation) that can
37. single nucleotide polymorphism (SNP)- A single base-pair site in a genome where nucleotide
variation is found in at least 1% of the population.
38. 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.
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39. 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.
40 sticky end-A single-stranded end of a double-stranded restriction fragment.
41. 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.
42. yeast artificial chromosome (YAC)-A cloning vector that combines the essentials of a
eukaryotic chromosome—an origin for DNA replication, a centromere, and two telomeres—with
foreign DNA.
Word Roots
electro- = electricity (electroporation: a technique to introduce recombinant DNA into cells by
applying a brief electrical pulse to a solution containing cells)
liga- = bound, tied (DNA ligase: a linking enzyme essential for DNA replication)
muta- = change; -genesis = origin, birth (in vitro muta-genesis: 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)
poly- = many; morph- = form (single nucleotide polymorphisms: one-base-pair variations in the
genome sequence)
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