Term
| Deoxyribose sugar in DNA is less reactive because --. stable in -- |
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Definition
C-H bonds. 2'c
Stable in alkaline conditions. |
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Term
| Ribose sugar is more reactive because of -- not stable in -- |
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Definition
C-OH (hydroxyl) bonds. 2'c
alkaline conditions and cellular conditions |
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Term
| Proofreading by RNA polymerase is Considered unnecessary, because: |
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Definition
rna doesn't carry permanent genetic info and a change would only affect 1 generation
Rna is rapidly degraded bc of 2'-OH group
Inaccurate proteins are degraded |
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Term
| exons vs introns and who expresses it: |
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Definition
| Exon = "expressed" region; intron = "intervening" region: Eukaryotes but not prokaryotes |
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Term
Heterogeneous nuclear RNA =
aka- |
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Definition
Original transcript that must be processed before it becomes fully functional
precursor mRNA (pre-mRNA) |
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Term
Modifications of pre-mRNA=
occur- |
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Definition
5' cap
3' polyadenylation
splicing
IN NUCLEUS |
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Term
| 5' cap and 3' polyA tail do what? |
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Definition
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Term
| self splicing vs spliceosome-mediated splicing- |
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Definition
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Term
| starting point for 5' cap is |
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Definition
| 5' end of an RNA molecule. This features a final nucleotide followed by three phosphate groups attached to the 5' carbon. |
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Term
| for the 5' cap of mRNA to form what is added and where? |
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Definition
GTP adds to nucleus
CH3 groups added to cytosol |
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Term
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Definition
| terminal nt has 5' 5' triphosphate link which then has a methylated guanine |
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Term
| Addition of the poly(A) tail to the primary RNA transcript of eukaryotes. |
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Definition
RNA endonuclease recognizes AAUAA, cleaves RNA 10-30 nucleotides downstream.
Polyadenylate polymerase adds 80-250 nucleotides, using ATP |
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Term
| Polyadenylation signals in mammalian cells consist of |
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Definition
AAUAA
and up and downstrem G-U rich elements |
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Term
mRNA is -- synthesized but on -% of cellular RNA bc of-
lifetime time and depends on |
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Definition
constantly
5% degraded
lifetime 1hr-lday depends on shortening of polyA tail(decapping), 3'-UTR, exonucleases find access |
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Term
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Definition
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Term
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Definition
| complex of 5 snRNPs ("Snurps") Small nuclear ribonucleoproteins = protein(s) + snRNA |
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Term
| Splicing mechanism in mRNA primary transcripts. |
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Definition
2'-OH of the A at the branch site attacks the 5'-P of the G to form a 2'→5' AG phosphodiester bond forming a lariat
Then the new free 3'-OH attacks 5'-P of base next to other G to remove lariat
lariat is degraded |
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Term
~23,000 genes can code for ~-- proteins
~--% of human genes exhibit alternate splicing |
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Definition
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Term
| Alternate splicing can produce |
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Definition
| multiple related proteins from a single gene |
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Term
% of all genetic diseases are a result of mutations that affect RNA splicing
example: |
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Definition
15%
many beta-thalassemia genotypes - lead to frame shifts |
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Term
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Definition
evolution, eukaryotic genes have been assembled from smaller, primitive genes — today's exons.
OR
simply the opportunity they provide for making many different proteins from a single gene through alternative splicing. |
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Term
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Definition
| Operons = clusters of genes that are regulated together |
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Term
| Operons can have one promoter and produce one strand of RNA, but code for |
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Definition
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Term
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Definition
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Term
| TRP operon in E. coli example: |
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Definition
5 gene (trpA - trpE) products required for synthesis of tryptophan in E. coli
• These products are produced together under control of a single promoter (P)
• Resulting mRNA message is "polycistronic" |
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Term
| Transcription factors (in eukaryotes) |
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Definition
| = proteins that bind to specific DNA sequences, thereby controlling rate of RNA polymerase II reaction |
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Term
| transcription factors -- rna polymerase |
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Definition
| ↑ (= activator) or ↓ (= repressor) RNA polymerase |
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Term
| Transcription factors contain one or more == which attach to specific |
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Definition
DNA-binding domains
sequences of DNA adjacent to the genes that they regulate |
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Term
| transcription factor location |
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Definition
(Usually) distant from the promoter in sequence of DNA
• Upstream or downstream from the gene
• On the other DNA strand or even on another chromosome |
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Term
| Protein-DNA complex approaches promoter due to |
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Definition
| long loops in the DNA via nucleosome remodeling |
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Term
| Location of enhancer or suppressor regions on DNA |
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Definition
| upstream or downstream 100s or 1000s BP can seperate them from the gene it regulates |
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Term
Estrogen
Receptors
Trigger |
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Definition
| gene activation and influence cell behavior |
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Term
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Definition
| confromation change of membrane-protein receptor causing homo or hetero dimers with other hormone-receptors called HRE hormone response elements (DNA)_> this regulates transcription of adjacent genes |
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