Chapter 15 Flashcards Preview

Biology 107 > Chapter 15 > Flashcards

Flashcards in Chapter 15 Deck (78):
1

hypothesis showing the direct relationship between genes and enzymes

one gene-one enzyme hypothesis

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

one gene-one polypeptide hypothesis

3

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

transcription

4

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

translation

5

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

central dogma

6

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

template strand

7

A gene encoding a protein

protein-coding gene

8

an RNA molecule that serves as a template for protein synthesis

messenger RNA (mRNA)

9

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

genetic code

10

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

codon

11

a codon that specifies an amino acid

sense codons

12

the first codon read in an mRNA in translation-AUG

start codon/ initiator codon

13

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

stop codons/nonsense codon/termination codon

14

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

degeneracy

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

commaless

16

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

universal

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

promoter

18

a region of DNA that transcribes a single primary transcript

transcription unit

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

initiation

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

transcription factor (TF)

21

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

RNA polymerase

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

elongation

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

termination

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

transcription factors

25

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

terminators

26

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

noncoding RNA genes

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

5' untranslated region (5' UTR)

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

3' untranslated region (3' UTR)

29

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

precursor-mRNA (pre-mRNA)

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

5' cap

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

polyadenylation signal

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

poly(A) tail

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

introns

34

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

exons

35

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

mRNA splicing

36

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

spliceosome

37

a complex of RNA and proteins

small ribonucleoprotein particles

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

alternative splicing

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

exon shuffling

40

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

transfer RNA (tRNA)

41

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

anticodon

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

wobble hypothesis

43

the process of adding an amino acid to a tRNA

aminoacylation/charging

44

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

auxotrophs

45

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

aminoacyl-tRNA

46

an enzyme that catalyzes aminoacylation

aminoacyl-tRNA synthetase

47

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

ribosomes

48

the RNA component of ribosomes

ribosomal RNA (rRNA)

49

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

A(aminoacyl) site

50

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

P(peptidyl) site

51

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

E(exit) site

52

a protein that aids an initiation step of translation

initiation factors (IF)

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

ribosome binding site

54

the series of codons for a polypeptide encoded by the mRNA

reading frame

55

a protein that aids in an elongation step of translation

elongation factor (EF)

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

peptidyl transferase

57

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

peptidyl-tRNA

58

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

ribozyme

59

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

release factor/termination factor

60

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

polysome

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

chaperones/chaperonins

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

signal peptide/signal sequence

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

cotranslational import

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

posttranslational import

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

transit sequences

66

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

nuclear localization signals

67

a spontaneous and heritable change in DNA

mutations

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

missense mutation

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

nonsense mutation

70

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

silent mutation

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

frameshift mutation

72

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

transposable element (TEs)

73

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

transposition

74

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

target site

75

transposable element that contains only genes for its transposition

insertion sequences

76

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

transposase

77

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

transposon

78

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

retrotransposons