Ch 10 From DNA to Proteins Flashcards

1
Q

ribosomal RNA (rRNA)

A

along with ribosomal protein subunits, makes up the ribosome

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2
Q

messenger RNA (mRNA)

A

carries the coding instructions for polypeptide chains from DNA to the ribosome

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3
Q

pre-messenger RNAs (pre-mRNAs)

A

large precursor molecules; are the immediate products of transcription in eukaryotic cells
not found in bacterial cells

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4
Q

transfer RNA (tRNA)

A

serves as the link between the coding sequence of nucleotides in an mRNA molecule and the amino acid sequence of a polypeptide chain

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5
Q

small nuclear RNAs (snRNAs)

A

combine with small protein subunits to form small nuclear ribonucleoproteins (snRNPs)

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6
Q

small nucleolar RNAs (snoRNAs)

A

takes part in the processing of rRNA

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7
Q

microRNAs (miRNAs) and small interfering RNAs (siRNAs)

A

two types of very small and abundant RNA molecules found in the cytoplasm of eukaryotic cells

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8
Q

RNA interference (RNAi)

A

a process in which these small RNA molecules help trigger the degradation of mRNA or inhibit its translation into protein

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9
Q

three major components of transcription

A

1) A DNA template
2) The raw materials (ribonucleotide triphosphates) needed to build a new RNA molecule
3) The transcription apparatus, consisting of the proteins necessary for catalyzing the synthesis of RNA

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10
Q

template strand

A

the nucleotide strand used for transcription

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11
Q

nontemplate strand

A

not ordinarily transcribed

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12
Q

transcription unit

A

a stretch of DNA that encodes an RNA molecule and the sequences necessary for its transcription

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13
Q

promoter

A

a DNA sequence that the transcription apparatus recognizes and binds
indicates which of the two DNA strands is to be read as the template and the direction of transcription

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14
Q

RNA-coding region

A

a sequence of DNA nucleotides that is copied into an RNA molecule

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15
Q

three critical regions within a transcription unit

A

a promoter, an RNA-coding sequence, and a terminator

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16
Q

terminator

A

a sequence of nucleotides that signals where transcription is to end

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17
Q

ribonucleoside triphosphates

A

RNA is synthesized from this

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18
Q

RNA polymerase

A

carries out all the required steps of transcription

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19
Q

core enzyme

A
five subunits (individual polypeptide chains) make up this
enzyme catalyzes the elongation of the RNA molecule by the addition of RNA nucleotides
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20
Q

sigma factor

A

controls the binding of RNA polymerase to the promoter

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21
Q

holoenzyme

A

sigma factor associates with the core enzyme

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22
Q

consensus sequences

A

short stretches of common nucleotides; they possess considerable similarity, or consensus

23
Q

10 consensus sequence

A

sometimes called the Pribnow box

written simply as TATAAT

24
Q

35 consensus sequence

A

sequence common to most bacterial promoters is TTGACA, which lies approximately 35 nucleotides upstream of the start site

25
Q

Rho-dependent terminators

A

able to cause the termination of transcription only in the presence of an ancillary protein called the rho factor

26
Q

Rho-independent terminators

A

also known as intrinsic terminators

able to cause the end of transcription in the absence of rho

27
Q

rho utilization site (rut)

A

serves as a binding site for the rho protein, which binds the RNA and moves toward its 3’ end, following the RNA polymerase

28
Q

hairpin

A

inverted repeats (sequences of nucleotides on the same strand that are inverted and complementary) are transcribed into RNA and bind to each other, forms this secondary structure

29
Q

polycistronic RNA

A

produced when a single terminator is present at the end of a group of several genes that are transcribed together, instead of each gene having its owen terminator

30
Q

exons

A
  • many eukaryotic genes contain these coding regions

- are joined to yield the mature RNA

31
Q

introns

A

noncoding regions called intervening sequences
common in eukaryotic genes but are rare in bacterial genes
tend to be longer than exons
do not encode proteins

32
Q

codon

A

in mRNA, each amino acid in a protein is specified by a set of three nucleotides

33
Q

three primary regions of prokaryotic and eukaryotic mRNAs

A

5’ untranslated region, the protein-coding region, and the 3’ untranslated region

34
Q

5’ untranslated region

A

5’ UTR, sometimes called the leader

a sequence of nucleotides at the 5’ end of the mRNA, does not encode any of the amino acids of a protein

35
Q

Shine-Dalgarno sequence

A

a consensus sequence (UAAGGAGGU) which serves as the ribosome-binding site during translation
found approximately seven nucleotides upstream of the first codon translated into an amino acid (the start codon)

36
Q

protein-coding region

A

comprises the codons that specify the amino acid sequence of the protein
begins with a start codon and ends with a stop codon

37
Q

5’ untranslated region

A

3’ UTR, sometimes called a trailer

a sequence of nucleotides that is at the 3’ end of the mRNA and is not translated into protein

38
Q

5’ cap

A

cap consists of an extra modified nucleotide at the 5’ end of the mRNA as well as methyl groups (CH3) on the 2’-OH group of the sugar of one or more nucleotides at the 5’ end

39
Q

poly(A) tail

A

addition of 50-250 or more adenine nucleotides at the 3’ end; these nucleotides are not encoded in the DNA, but are added after transcription in a process termed polyadenylation

40
Q

RNA splicing

A

removal of introns

takes places in the nucleus, before the RNA moves to the cytoplasm

41
Q

5’ splice site and 3’ splice site

A

these splice sites possess short consensus sequences

42
Q

branch point

A

an adenine nucleotide that lies from 18 to 40 nucleotides upstream of the 3’ splice site

43
Q

spliceosome

A

splicing takes place within a large structure which is one of the largest and most complex of all molecular structures

44
Q

lariat

A

pre-mRNA is cut at the 5’ splice site which frees exon 1 from the intron, and the 5’ end of the intron attaches to the branch point; that is, the intron folds back on itself

45
Q

alternative processing

A

many eukaryotic mRNAs undergo this which is a single pre-mRNA is processed in different ways to produce alternative types of mRNA, resulting in the production of different proteins from the same DNA sequence

46
Q

alternative splicing

A

the same pre-mRNA can be spliced in more than one way to yield multiple mRNAs that are translated into different amino acid sequences and thus different proteins

47
Q

cloverleaf structure

A

some of the nucleotides in a tRNA are complementary to each other and form intramolecular hydrogen bonds which results in this

48
Q

anticodon

A

a set of three nucleotides which pairs with the corresponding codon on the mRNA during protein synthesis to ensure that the amino acids link in the correct order

49
Q

trimming

A

additional nucleotides may then be removed one at a time from the 5’ and 3’ ends of the tRNA in a process known as this

50
Q

two subunits of a functional ribosome

A

large ribosomal subunit and small ribosomal subunit

51
Q

RNA interference (RNAi)

A

a powerful and precise mechanism used by eukaryotic cells to limit the invasion of foreign genes (from viruses and transposons) and to censor the expression of their own genes
triggered by double-stranded RNA molecules, which may arise in several ways: by the transcription of inverted repeats into an RNA molecule that then base pairs with itself to form double-stranded RNA; by the simultaneous transcription of two different RNA molecules that are complementary to one another and that pair, forming double-stranded RNA; or by infection by viruses that make double-stranded RNA

52
Q

two abundant classes of RNA molecules that function in RNA

A

small interfering RNA and microRNAs

53
Q

RNA-induced silencing complex (RISC)

A

both siRNA and miRNA molecules combine with proteins to form this
the key to functioning of RISCs is a protein called Argonaute

54
Q

CRISPR RNAs

A

Assist in the destruction of foreign DNA molecules