ch 20 molecular technologies

Question 1

recombinant dna technology

Answer 1

the use of in vitro molecular techniques to to manipulate fragments of dna to produce new arrangements

Question 2

recombinant dna molecules

Answer 2

molecules that are produced in a test tube by covalently linking dna fragments from two different sources

Question 3

gene cloning

Answer 3

the production of many copies of a gene using molecular methods, such as pcr or the introduction of the gene in to a vector that replicates in a host cell

Question 4

vector

Answer 4

a small dna molecule that is used as a carrier of a dna segment into a cloning experiment

Question 5

host cell

Answer 5

a cell that is infected with a virus of bacterium, or one that harbors a vector

Question 6

plasmid

Answer 6

a general term for a dna molecule (most often circular) that exists independently of the chromosomal dna; some plasmids are used as vectors in cloning experiments

Question 7

R factor

Answer 7

a type of plasmid found commonly in bacteria that gives resistance to a toxic substance, such as an antibiotic

Question 8

origin of replication

Answer 8

a site on a chromosome that functions as an initiation site for the assembly of several proteins that begins the process of dna replication

Question 9

selectable marker

Answer 9

a gene that provides a selectable phenotype in a cloning experiment; many markers are genes that give antibiotic resistance

Question 10

shuttle vector

Answer 10

a cloning vector that can propagate in two or more different species, such as e. coli or yeast

Question 11

expression vector

Answer 11

a cloning vector that contains a promoter so that the gene of interest is transcribed into rna when the vector is introduced into a host cell

Question 12

restriction enzyme

Answer 12

(also called restriction endonuclease) an endonuclease that cleaves dna; restriction enzymes used in cloning experiments bind to specific base sequences and then cleave the dna backbone at two defined locations, one in each strand

Question 13

dna ligase

Answer 13

an enzyme that catalyzes the formation of a covalent bond within the sugar-phosphate backbones of two dna strands

Question 14

palindromic

Answer 14

describes sequences in the two strands of a dna molecule that are identical when read in opposite directions

Question 15

recombinant vector

Answer 15

a vector that contains an inserted fragment of dna such as a gene from a chromosome

Question 16

competent cells

Answer 16

cells that can take up dna from the environment or an extracellular medium

Question 17

transformation

Answer 17

1. when a bacterial cell takes up a plasmid vector or segments of chromosomal dna from the environment
2. when a normal cell is converted into a malignant cell

Question 18

reverse transcriptase

Answer 18

an enzyme that uses an rna template to make a double stranded dna molecule

Question 19

complementary dna (cDNA)

Answer 19

dna that is made form an rna template by the action of reverse transcriptase

Question 20

dna library

Answer 20

a collection of many recombinant vectors, each carrying a particular fragment od dna from a larger source; for example, each recombinant vector in a dna library might carry a small segment of chromosomal dna from a particular species

Question 21

genomic library

Answer 21

a dna library of recombinant vectors that carry chromosomal dna fragments

Question 22

cDNa library

Answer 22

a dna library whose recombinant vector carry cdna inserts

Question 23

polymerase chain reaction (PCR)

Answer 23

the method for amplifying a dna region involving the sequential use of oligonucleotide primers and Taq polymerase

Question 24

primer

Answer 24

a short segment of dna or rna that initiates dna replication

Question 25

template dna

Answer 25

a sample of dna, such as chromosomal dna, that is used in a pcr experiment

Question 26

Taq polymerase

Answer 26

a thermostable form of dna polymerase used in pcr experiments

Question 27

primer annealing

Answer 27

in PCR, the process in which a primer binds to a strand of template dna

Question 28

primer extension

Answer 28

in pcr, the step during which complementary strands of dna are synthesized from the denatured template dna, staring primers

Question 29

thermocycler

Answer 29

a device that automates the timing of temperature changes in each cycle of a pcr experiment

Question 30

reverse transcriptase PCR

Answer 30

a modification of pcr in which the first round of replication involves the use of rna and reverse transcriptase to make a complementary strand of dna

Question 31

real-time pcr

Answer 31

a method of pcr in which the synthesis of dna is monitored in real time; this method can quantitate the starting amount of dna in a sample

Question 32

cycle threshold method

Answer 32

(also called Ct method) in quantitative pcr, a method of determining the starting amount of dna based on a threshold level at which the accumulation of fluorescence in significantly greater than the background level

Question 33

dna sequencing

Answer 33

a method for determining the base sequence in a segment of dna

Question 34

dideoxy sequencing

Answer 34

a method of dna sequencing that uses dideoxyribonucleotides to terminate growth of dna strands

Question 35

dideoxyribonucleotide (ddNTP)

Answer 35

a nucleotide used in dna sequencing that is missing the 3’ –OH group; if a dideoxyribonucleotide is incorporated into a dna strand, it stops any further growth of the strand

Question 36

chain termination

Answer 36

an event that stops the growth of a dna stand, rna strand or polypeptide

Question 37

automated dna sequencing

Answer 37

the use of fluorescently labeled dideoxyribonucleotides and a fluorescence detector to sequence dna

Question 38

sequencing ladder

Answer 38

a series of bands on a gel that can be followed in order (ie from the bottom of the gel to the top of the gel) to determine the base sequence of a stand of dna

Question 39

gene editing

Answer 39

experimentally altering the sequence of a gene

Question 40

site-directed mutagenesis

Answer 40

a gene-editing technique that allows a researcher to produce a mutation at a specific location within a cloned dna segment by using an oligonucleotide primer with a mismatch

Question 41

CRISPR-Cas technology

Answer 41

a method that uses the components of the crispr-cas system of genome defense found in prokaryotes to introduce mutations into genes

Question 42

northern blotting

Answer 42

a technique used to detect a specific rna within a mixture of many rna molecules

Question 43

western blotting

Answer 43

a technique used to detect a specific protein within a mixture of proteins

Question 44

antibodies

Answer 44

(also known as immuniglobins) proteins that are produced by the immune system of vertebrates, which recognize foreign material (ie viruses, bacteria, etc) and target it for destruction

Question 45

epitope

Answer 45

the structure on the surface of an antigen that is recognized by an antibody

Question 46

antigen

Answer 46

foreign substances that elicit an immune response because they are recognized by antibodies

Question 47

electrophoretic mobility shift assay (EMSA)

Answer 47

(also called gel retardation assay) a technique for studying protein-dna or protein-rna interactions in which the binding of proteins to dna fragments retards its mobility during gel electrophoresis

Question 48

DNase I footprinting

Answer 48

a method for studying protein-dna interactions in which the binding a protein to dna protects the dna from digestion by dnase i