Ch.8 Interactive Glossary

Question 1

A agent that causes tumors in humans.

Answer 1

Carcinogen

Question 2

A bacterial protein toxic to other bacteria.

Answer 2

Bacteriocin

Question 3

A change in the characteristic of an organism arising from a permanent alteration of a DNA sequence in a gene.

Answer 3

Mutation

Question 4

A diagnostic procedure used to detect potential cancer agents by their ability to cause back mutations in Salmonella cells.

Answer 4

Ames test

Question 5

A molecule of RNA that unites with amino acids and transports them to the ribosome during protein synthesis.

Answer 5

Transfer RNA (tRNA)

Question 6

A mutant cell that has regained a physiological or biochemical property.

Answer 6

Revertant

Question 7

A mutant selection technique where one identifies colonies missing on a minimal medium plate.

Answer 7

Negative selection

Question 8

A mutation arising from a mutagenic agent used under controlled laboratory conditions.

Answer 8

Induced mutation

Question 9

A mutation that arises from chance events in the environment.

Answer 9

Spontaneous mutation

Question 10

A nucleotide segment removed after transcription of a eukaryotic messenger RNA.

Answer 10

Intron

Question 11

A segment of DNA that forms a copy of itself, after which the copy moves into areas of gene activity to interrupt the genetic coding sequence.

Answer 11

Insertion sequence

Question 12

A segment of DNA that moves from one site on a DNA molecule to another site, carrying information for protein synthesis; also known as a jumping gene.

Answer 12

Transposon

Question 13

A segments of DNA resulting from discontinuous DNA replication.

Answer 13

Okazaki fragment

Question 14

A selection technique where one is looking for colonies growing on a minimal medium plate.

Answer 14

Positive selection

Question 15

A small, circular DNA molecule that occurs frequently in bacteria and carries genes for drug resistance; also called R factor.

Answer 15

R plasmid

Question 16

A small, closed-loop molecule of DNA apart from the chromosome; plasmids carry genes for drug resistance and pilus formation, and are used in genetic engineering techniques.

Answer 16

Plasmid

Question 17

A three-base sequence on the mRNA molecule that specifies a particular amino acid in the protein molecule.

Answer 17

Codon

Question 18

A three-base sequence on the tRNA molecule that binds to the codon on the mRNA molecule during translation.

Answer 18

Anticodon

Question 19

A type of DNA replication in which a strand of DNA “rolls off” the loop and serves as a template for the synthesis of a complementary strand of DNA.

Answer 19

Rolling circle mechanism

Question 20

An alteration in the genetic information in a microorganism arising from the acquisition of DNA; in bacterial cells, recombination occurs by transformation, conjugation, or transduction.

Answer 20

Recombination

Question 21

An enzyme that catalyzes DNA replication by combining complementary nucleotides to an existing template strand.

Answer 21

DNA polymerase

Question 22

An enzyme that catalyzes RNA synthesis by combining complementary nucleotides to one strand of a gene.

Answer 22

RNA polymerase

Question 23

An enzyme that joins together separate Okazaki fragments during DNA replication.

Answer 23

DNA ligase

Question 24

An organism that contains all its nutritional needs in the medium.

Answer 24

Auxotroph

Question 25

An organism that lacks a nutritional need.

Answer 25

Prototroph

Question 26

An RNA transcript containing the information for synthesizing a specific polypeptide.

Answer 26

Messenger RNA (mRNA)

Question 27

An RNA transcript that forms part of the ribosome’s structure.

Answer 27

Ribosomal RNA (rRNA)

Question 28

One of the genes transcribed in an operon.

Answer 28

Structural gene

Question 29

That portion of an operon where a repressor protein binds.

Answer 29

Operator

Question 30

That portion of an operon where the RNA polymerase binds.

Answer 30

Promoter

Question 31

The biochemical process in which RNA is synthesized according to a code supplied by the bases of a gene in the DNA molecule.

Answer 31

Transcription

Question 32

The biochemical process in which the code on the mRNA molecule is translated into a sequence of amino acids in the protein molecule.

Answer 32

Translation

Question 33

The complete set of genes in a virus or an organism.

Answer 33

Genome

Question 34

The continuous strand synthesized during DNA replication.

Answer 34

Leading strand

Question 35

The discontinuous strand synthesized during DNA replication.

Answer 35

Lagging strand

Question 36

The doctrine stating that DNA is transcribed into RNA, which is then translated into protein.

Answer 36

Central dogma

Question 37

The first codon (AUG) translated in a mRNA.

Answer 37

Start codon

Question 38

The form of gene control where a repressor protein binds to an operator unless inhibited; the lactose (lac) operon is an example.

Answer 38

Negative control

Question 39

The gene outside an operon that codes for a repressor protein.

Answer 39

Regulatory gene

Question 40

The genetic material of all cells and some viruses.

Answer 40

Deoxyribonucleic acid (DNA)

Question 41

The last codon (UGA, UAA, or UAG) in an mRNA read but not translated by a ribosome.

Answer 41

Stop codon

Question 42

The mature eukaryotic mRNA produced after introns have been removed.

Answer 42

Exon

Question 43

The protein that binds to the operator in an operon.

Answer 43

Repressor protein

Question 44

The twisting and tight packing of the DNA into a chromosome.

Answer 44

Supercoiling

Question 45

The type of replication carried out by all organisms where each double helix is composed of one old and one new polynucleotide strand.

Answer 45

Semiconservative replication

Question 46

The unit of bacterial DNA that controls and expresses a particular set of structural genes.

Answer 46

Operon