Chapter 15

Question 1

hypothesis showing the direct relationship between genes and enzymes

Answer 1

one gene-one enzyme hypothesis

Question 2

restatement of this one gene-one enzyme hypothesis, taking into account that some proteins consist of more than one polypeptide and not all proteins are enzyme

Answer 2

one gene-one polypeptide hypothesis

Question 3

the mechanism by which the information encoded in DNA is made into a complementary RNA copy

Answer 3

transcription

Question 4

the use of the information encoded in mRNA to assemble amino acids into a polypeptide

Answer 4

translation

Question 5

the name give by Francis Crick to the flow of information from DNA to RNA to protein

Answer 5

central dogma

Question 6

The DNA strand that is copied into an RNA molecule during gene transcription

Answer 6

template strand

Question 7

A gene encoding a protein

Answer 7

protein-coding gene

Question 8

an RNA molecule that serves as a template for protein synthesis

Answer 8

messenger RNA (mRNA)

Question 9

the nucleotide information that specifies the amino acid sequence of a polypeptide

Answer 9

genetic code

Question 10

each 3-letter word (triplet) of the genetic code

Answer 10

codon

Question 11

a codon that specifies an amino acid

Answer 11

sense codons

Question 12

the first codon read in an mRNA in translation-AUG

Answer 12

start codon/ initiator codon

Question 13

A codon that does specify amino acids. the 3 nonsense codons are UAG, UAA, and UGA

Answer 13

stop codons/nonsense codon/termination codon

Question 14

the feature of the genetic code in which with 2 exceptions, more than one codon represents each amino acid

Answer 14

degeneracy

Question 15

the sequential nature of the words of the nucleic acid code, with no indicators such as commas or spaces to mark the end of one codon and the beginning of the next

Answer 15

commaless

Question 16

A feature of the nucleic acid code, with the same codons specifying the same amino acids in all living organisms

Answer 16

universal

Question 17

the site to which RNA polymerase binds(prokaryotes) or to which general transcription factors bind and recruit RNA polymerase (eukaryotes) for initiating transcription of a gene

Answer 17

promoter

Question 18

a region of DNA that transcribes a single primary transcript

Answer 18

transcription unit

Question 19

in transcription, the step in which the molecular machinery that carries out transcription assembles at the promoter and begins synthesizing an RNA copy of the gene. in translation, the step in which the translation components assemble on the start codon of the mRNA

Answer 19

initiation

Question 20

in eukaryotes, the proteins required for RNA polymerase to initiate transcription or that regulate that process. one class of transcription factors recognizes and binds to the promoter in the area of the TATA box and then recruit RNA polymerase

Answer 20

transcription factor (TF)

Question 21

an enzyme that catalyzes the assembly of ribonucleotides into and RNA strand

Answer 21

RNA polymerase

Question 22

in transcription, the step in which RNA polymerase (RNA polymerase II in eukaryotes) moves along the gene extending the RNA chain, with the DNA continuing to unwind ahead of the enzyme. in translation, the step in which the assembled translation complex reads the string of codons in the mRNA one at a time while joining the specified amino acids into the polypeptide

Answer 22

elongation

Question 23

in transcription, the step in which transcription ends and the RNA transcript and RNA polymerase (RNA polymerase II in the case of eukaryotes) are released from the DNA template. in translation, the step in which the translation complex disassembles after the last amino acid of the polypeptide specified by the mRNA has been added to the polypeptide

Answer 23

termination

Question 24

in eukaryotes, the proteins required for RNA polymerase to initiate transcription or that regulate that process. one class of transcription factors recognizes and binds to the promoter in the area of the TATA box and then recruit RNA polymerase

Answer 24

transcription factors

Question 25

specific DNA sequence for a gene that signals the end of transcription of a gene. terminators are common for prokaryotic genes

Answer 25

terminators

Question 26

a gene encoding an RNA that is not translated; that is, a gene other than a protein-coding gene

Answer 26

noncoding RNA genes

Question 27

the part of an mRNA between the 5' end of the molecule and the start codon; this region does not code for amino acids

Answer 27

5' untranslated region (5' UTR)

Question 28

the part of an mRNA between the stop codon and the 3' end of the molecule; this region does not code for amino acid

Answer 28

3' untranslated region (3' UTR)

Question 29

the primary transcript of a eukaryotic protein-coding gene, which is processed to form messenger RNA

Answer 29

precursor-mRNA (pre-mRNA)

Question 30

in eukaryotes, a guanine-containing nucleotide attached in a reverse orientation to the 5' end of pre-mRNA and retained in the mRNA produced form it. on an mRNA is the site where ribosomes attach to initiate translation

Answer 30

5' cap

Question 31

sequence near the 3' end of a eukaryotic gene which, in the pre-mRNA transcript of the gene, specifies where the transcript should be cleaved. once cleaved, a poly(A) tail is added to the 3' end of the RNA

Answer 31

polyadenylation signal

Question 32

the string of A nucleotides added posttranscriptionally to the 3' end of a cleaved pre-mRNA molecule and retained in the mRNA produced from it that enables the mRNA to be translated efficiently and protects it from attack by RNA-digesting enzymes in the cytoplasm

Answer 32

poly(A) tail

Question 33

a non-protein-coding sequence that interrupts the protein-coding sequence in a eukaryotic gene and are removed by splicing in the processing of pre-mRNA to mRNA

Answer 33

introns

Question 34

an amino acid-coding sequence present in pre-mRNA that is retained in a spliced mRNA that is translated to produce a polypeptide

Answer 34

exons

Question 35

process that removes introns from pre-mRNAs and joins exons together

Answer 35

mRNA splicing

Question 36

a complex formed between the pre-mRNA and small ribonucleoprotein particles, in which mRNA splicing takes place

Answer 36

spliceosome

Question 37

a complex of RNA and proteins

Answer 37

small ribonucleoprotein particles

Question 38

mechanism by which a pre-mRNA in a eukaryotic cell is processed by reactions that join exons in different combinations to produce different mRNAs from a single gene

Answer 38

alternative splicing

Question 39

molecular evolutionary process that combines exons of 2 or more existing genes to produce a gene that encodes a protein with an unprecedented function

Answer 39

exon shuffling

Question 40

the RNA that brings amino acids to the ribosome for addition to the polypeptide chain

Answer 40

transfer RNA (tRNA)

Question 41

the 3-nucleotide segment in a tRNA that pairs with a codon in an mRNA

Answer 41

anticodon

Question 42

hypothesis stating that the complete set of 61 sense codons can be read by fewer than 61 distinct tRNAs because of particular pairing properties of the bases in the anticodons

Answer 42

wobble hypothesis

Question 43

the process of adding an amino acid to a tRNA

Answer 43

aminoacylation/charging

Question 44

a mutant strain that requires for its growth a nutrient supplement that i not needed by the wild-type strain

Answer 44

auxotrophs

Question 45

a tRNA linked to its "correct" amino acid, which is the finished product of aminoacylation

Answer 45

aminoacyl-tRNA

Question 46

an enzyme that catalyzes aminoacylation

Answer 46

aminoacyl-tRNA synthetase

Question 47

a ribonucleoprotein particle that carries out protein synthesis by translating mRNA into chains of amino acids

Answer 47

ribosomes

Question 48

the RNA component of ribosomes

Answer 48

ribosomal RNA (rRNA)

Question 49

the site where the incoming aminoacyl-tRNA carrying the next amino acid to be added to the polypeptide chain binds to the mRNA

Answer 49

A(aminoacyl) site

Question 50

the site in the ribosome where the tRNA carrying the growing polypeptide chain is bound during translation

Answer 50

P(peptidyl) site

Question 51

the site where an existing tRNA binds before its release from the ribosome in translation

Answer 51

E(exit) site

Question 52

a protein that aids an initiation step of translation

Answer 52

initiation factors (IF)

Question 53

in translation initiation in prokaryotes, a sequence just upstream of the start codon that directs the small ribosomal subunit to bind and orient correctly for the complete ribosome to assemble and start translating in the correct spot

Answer 53

ribosome binding site

Question 54

the series of codons for a polypeptide encoded by the mRNA

Answer 54

reading frame

Question 55

a protein that aids in an elongation step of translation

Answer 55

elongation factor (EF)

Question 56

an enzyme that catalyzes the reaction in which an amino acid is cleaved from the tRNA in the P site of the ribosome and forms a peptide bond with the amino acid on the tRNA in the A site of the ribosome

Answer 56

peptidyl transferase

Question 57

A tRNA linked to a growing polypeptide chain containing 2 or more amino acids

Answer 57

peptidyl-tRNA

Question 58

an RNA-based catalyst that is part of the biochemical machinery of all cells

Answer 58

ribozyme

Question 59

a protein that recognizes stop codons in the A site of a ribosome translating an mRNA and terminates translation

Answer 59

release factor/termination factor

Question 60

the entire structure of an mRNA molecule and the multiple associated ribosomes that are translating it simultaneously

Answer 60

polysome

Question 61

"guide" protein that binds temporarily with newly synthesized proteins, directing their conformation toward the correct tertiary structure and inhibiting incorrect arrangements as the new proteins fold

Answer 61

chaperones/chaperonins

Question 62

a short segment of amino acids to which the signal recognition particle binds, temporarily blocking further translation. is found on polypeptides that are sorted to the endoplasmic reticulum

Answer 62

signal peptide/signal sequence

Question 63

a mechanism by which a polypeptide being sorted via the endomembrane system in a eukaryotic cell begins its import into the endoplasmic reticulum simultaneously with translation of the mRNA encoding the polypeptide

Answer 63

cotranslational import

Question 64

a mechanism by which proteins are sorted to their final cellular locations in a eukaryotic cell after they have been made on free ribosomes in the cytosol

Answer 64

posttranslational import

Question 65

short amino acid sequence on a protein that serves to direct the protein to the appropriate organelle (other than the nucleus or ER) in a eukaryotic cell

Answer 65

transit sequences

Question 66

a short amino acid sequence in a protein that directs the protein to the nucleus

Answer 66

nuclear localization signals

Question 67

a spontaneous and heritable change in DNA

Answer 67

mutations

Question 68

a base-pair substitution mutation in a protein-coding gene that results in a different amino acid in the encoded polypeptide than the normal one

Answer 68

missense mutation

Question 69

a base-pair substitution mutation in a gene in which the base-pair change results in a change from a sense codon to a nonsense codon in the mRNA. the polypeptide translated from the mRNA is shorter than the normal polypeptide because of the mutation

Answer 69

nonsense mutation

Question 70

a base-pair substitution mutations in a protein-coding gene that does not alter the amino acid specified by the gene

Answer 70

silent mutation

Question 71

mutation in a proteincoding gene that causes the reading frame of an mRNA transcribed from the gene to be altered, resulting in the production of a different, and nonfunctional, amino acid sequence in the polypeptide

Answer 71

frameshift mutation

Question 72

a sequence of DNA that can move from one place to another within the genome of a cell

Answer 72

transposable element (TEs)

Question 73

the movement of a transposable element from one site to another in a genome

Answer 73

transposition

Question 74

the location in a genome to which a transposable element moves when it transposes

Answer 74

target site

Question 75

transposable element that contains only genes for its transposition

Answer 75

insertion sequences

Question 76

an enzyme that catalyzes some of the reactions inserting or removing the transposable element from the DNA

Answer 76

transposase

Question 77

a bacterial transposable element with an inverted repeat sequence at each end enclosing a central region with one or more genes

Answer 77

transposon

Question 78

a transposable element that transposes via an intermediate RNA copy of the transposable element

Answer 78

retrotransposons