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59 Cards in this Set
- Front
- Back
RNA polymerase |
Binds in a precise location on promoter, determining where transcription starts and which DNA strand is used as template/In bacteria, it recognizes and binds to promoter |
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Transcription factors |
Group of proteins in eukary that mediate binding RNA poly and initiating transcription |
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After transcription factors attach to promoter |
Only when this happens do RNA poly II bind to it |
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Transcription initiation complex |
Complex of transcription factors and RNA poly II bound to the promoter |
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TATA box |
Crucial DNA sequence in promoter |
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Unwinds the two DNA strands |
When transcription factors are attached to promoter DNA and poly is bound to correct orientation, the enzyme does this and starts transcribing template strands |
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10 - 20 DNA nucleotides |
RNA moves along DNA and untwists it, exposing _________ at a time for pairing w/ RNA nucleos/The enzyme adds nucleotides to 3' end of RNA molecule |
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40 nucleotides per second |
Rate of transcription in eukary |
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Transcribed simultaneously |
A single gene can be _______________ by several molecules of RNA poly following each other |
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How far along the template the enzyme has traveled |
A growing strand of RNA trails from each poly, w/ the length of each new strand reflecting |
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To make encoded protein in large amounts |
Group of many poly molecules simultaneously transcribing a single gene increases amount of mRNA transcribed, which helps cells __________ |
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Terminator sequence |
Bacteria's transcription proceeds through this in DNA Termination signal Causes poly to detach from DNA and release transcript |
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RNA poly II |
In eukary, this transcribes the sequence on DNA called polyadenylation signal sequence, which codes for a polyden signal in pre-mRNA |
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pre-mRNA |
At 10-35 nucleos downstream, from polyden signal, proteins associated w/ growing RNA transcript cut is free from the polymerase, releasing ___________, which then goes through processing |
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RNA processing |
When enzymes in eukary nucleous modify pre-mRNA in specific ways before genetic messages go to cytoplasm |
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5' end |
This end in pr-mRNA is processed first |
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5' cap |
A modified form of guanine (G) added to 5' end after transcribing 20 - 40 nucleos |
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3' end |
End of pre-mRNA modified before it leaves nucleous |
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Poly-A-tail |
The 50-250 more adenines (A) added to 3' end |
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5' cap and poly-A-tail shared functions |
Facilitate the export of mature mRNA from nucleus Protect mRNA from degradation by hydrolytic enzymes Help ribosomes attach to 5' end when mRNA reaches cytoplasm |
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UTR |
Parts of mRNA not translated to protein and binds ribosomes |
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27,000 nucleo pairs |
Length of transcription unit along human DNA and RNA |
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Long non coding stretches |
Eukary genes have ____________ of nucleos untranslated |
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Coding segments |
Most non coding sequences are interspersed b/ween __________ of genes |
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DNA nucleo |
This sequence that codes for eukary polypeptide is usually not continuous, but split to segments |
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Introns |
Non coding segments of nucleic acid b/ween coding regions (intervening sequences) |
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Exons |
Other regions that are eventually expressed by being translated into amino acid squences |
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UTR |
Part of exon which makes part of mRNA, but aren't made into proteins |
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RNA splicing |
RNA poly II transcribes introns and extrons to make a primary transcript from a gene (mRNA is abridged version)/introns are cut and exons joined together forming mRNA molecule w/ continuous |
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More than one kind of polypeptide |
The presence of introns in genes causes a single gene to encode ______________ |
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Alternative RNA splicing |
Genes giving rise to two or more different polypeptides, depending on which segments are treated as exons during RNA processing |
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Spliceosome |
Proteins and small RNAs making a large complex that removes introns |
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Released and rapidly degraded |
This happens to the introns, then the spliceosome joins the two exons flanking the intron |
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Ribozome |
RNA molecules acting as enzymes |
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Intron RNA |
Functions as ribosome and catalyzes its own excision |
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Three properties that enable RNA to function as enzymes |
Being single stranded means a region of RNA can base-pair w/ a complementary region elsewhere/gives it 3D structure Some RNA bases have functional groups that participate in catalysis Can hydrogen bond w other nucleic acids which adds specificity to catalytic activity |
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Transfer RNA tRNA |
Translator of message in a series of codons along mRNA |
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Synthesizing them from other compounds or by taking them up from the surrounding solution |
Cells keep 20 amino acids in cytoplasm by _________ |
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The growing end of polypeptide chain |
The ribosome adds each amino acid brought by tRNA to _______________ |
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tRNA can translate an mRNA codon into amino acid |
Key to translating a genetic message into a specific amino acid sequence |
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tRNA has amino acid at one end and a nucleic triplet that can base-pair w/ complementary codon on mRNA |
How can tRNA translate an mRNA codon into amino acid |
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80 |
tRNA has single RNA strand is ________ nucleotides long |
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3D structure |
The presence of complementary stretches of nucleotide bases that can hydrogen bond to each other, the single strand can fold in on itself and form a molecule w/ ______________ |
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Anticodon |
Nucleotide triplet that base pairs to specific mRNA codon |
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Glycine |
When an mRNA goes through ribosome ____________ is added to polypeptide chain when codon GGC is presented for translation |
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Repeatedly |
The tRNA is used ___________ picking up designated amino acid in cytosol, deposits cargo on polypeptide chain at ribosome and leaving ribosome, is ready to start over |
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A tRNA that binds to mRNA codon specifying amino acid must carry that and no other to ribosome Pairing tRNA anticodon w/ appropriate mRNA codon |
Translation of genetic message needs two instances of molecular recognition |
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Aminoacyl-tRNA synthetases |
Family of enzymes that match tRNA and amino acids |
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20 |
There are this many different synthetases, one for each amino acid |
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Synthetases |
This is able to bind to all different tRNA that match codons of amino acids |
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Hydrolysis of ATP |
Synthetases catalyzes covalent attachments of the amino acid to its tRNA in a process driven by the ___________________ |
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Charged tRNA |
Resulting aminoacyl tRNA that is released from the enzyme and available to deliver amino acid to polypeptide chain on ribosome |
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Wobble |
Flexible base pairing at this codon position at third position at 3' end of an mRNA codon |
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tRNA anticodons |
Ribosomes facilitate the coupling of ___________ w/ mRNA codons during protein synthesis |
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Ribosomal RNAs rRNAs |
RNAs that make up ribosomes w/ proteins/most abundant type of RNA |
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Proteins imported from the cytoplasm |
Ribosomal RNA genes are transcribed and the RNA is processed and assembled w/ _____________ |
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Nuclear pores |
The resulting ribosmal subunits are exported via ___________ to the cytoplasm |
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Functional ribose |
Large and small subunits join to form ______________ only when they attach to mRNA |
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1/3 |
The mass of a ribosome are proteins/The rest are rRNAs (3 in bacteria, 4 in eukary) |