front 1 What do epigenetic changes involve? | back 1 both chemical and structural modifications to the chromatin and DNA |
front 2 What happens in the cytoplasm in terms of mRNA? | back 2 the stability of mRNA is controlled and its translatability |
front 3 DNA cannot function on its own because- | back 3 it can not perform the functions that proteins does, hence the production of proteins |
front 4 Define transcriptional control- | back 4 when and how often a gene sequence is copied into RNA |
front 5 What is a transcription factor? | back 5 they modulate gene expression to turn transcription on or off |
front 6 What are two categories of transcription factors? | back 6 -general (basal) -specific |
front 7 What is a general (basal) transcription factor? | back 7 they are abundant proteins that assemble on all genes transcribed by RNA polymerase II |
front 8 what is the function of a general (basal) transcription factor? | back 8 -important for basal activity of the promoter -positions and activates RNA polymerase II at the start of the protein-coding sequence |
front 9 Why are general transcription factors needed? | back 9 priming transcription |
front 10 Formation of the _____________ complex requires several _________ in addition to RNA polymerase ____ | back 10 transcription, proteins, II |
front 11 What is a specific transcriptional factor? | back 11 gene regulatory proteins that present in few copies in individual cells. |
front 12 What is the function of a specific transcriptional factor? | back 12 they bind to a specific DNA nucleotide sequence an allowing the genes that they control to be activated or repressed |
front 13 Why are specific transcription factors needed? | back 13 they are designed to bind specific DNA sequences and regulate gene transcription |
front 14 Transcriptions factors have a- | back 14 modular design consisting of at least 2 distinct domains (DNA binding and transcription activating domains) |
front 15 DNA binding consists of- | back 15 the structural notif that recognizes specific DNA sequences |
front 16 Transcription activating is- | back 16 the domain that contracts the transcriptional machinery and accelerates the rate of transcription initiation by accelerating the assemble of the general transcription factors at the promoter site |
front 17 Specific transcription factors influence the- | back 17 number of RNA polymerases that bind to DNA and initiate transcription. |
front 18 What is a spliceosome | back 18 removes noncoding segments (introns) from pre mRNA to make mature mRNA |
front 19 RNA processing control occurs- | back 19 in the nucleus and the subsequent processing is necessary to control the number of mRNA molecules that are translated |
front 20 why is the addition of the 5' cap structure so important? | back 20 - a mRNA to be translated in the cytoplasm -protects the growing RNA chain from degradation in the nucleus by 5' exonucelases |
front 21 What do exonucleases do? | back 21 degrade RNA kill RNA primers |
front 22 5' end of RNA is capped by a | back 22 methyl guanosine residue, which protects it from degradation (by 5' exonucleases) during elongation of RNA |
front 23 The 5' cap also helps- | back 23 the transcript binds to the ribosome during protein synthesis. |
front 24 The addition of a poly(A) tail occurs where? | back 24 3' end (abt 200 adenine residues are added) |
front 25 Why is the polyadenylation reaction important? | back 25 it is important from RNA stability and prevents premature degradation at the 3'end |
front 26 What specifically does the poly(A) tail protect from? | back 26 premature degradation by 3' exonucleases. |
front 27 since introns are noncoding they are | back 27 spliced |
front 28 Since exons are coding they can- | back 28 make different protein from one DNA double helix |
front 29 The splicing of introns occurs because- | back 29 the RNA will not leave the nucleus until the post-transcriptional modification are done, this makes mature mRNA |
front 30 Splice sites are- | back 30 present within the gene and delineate the introns |
front 31 Splice site sequences are found in | back 31 pre mRNA |
front 32 What is alternative splicing? | back 32 the ability of genes to form multiple proteins by joining different exon segments in the primary transcript i |
front 33 mature mRNA exits through the | back 33 nuclear pore complex |
front 34 All transcripts have a ______________ in the cell | back 34 finite life time (they get degraded, short life) |
front 35 The steady-state level of individual RNA species in a cell is determined by: | back 35 rate of transcription and rate of decay |
front 36 what is a half life? | back 36 a measure of degrative rate for a certain mRNA, the period it takes to degrade an RNA population to half its initial concentration. |
front 37 Unstable mRNAS- | back 37 usually code for regulatory proteins whose production levels change rapidly in cells |
front 38 Stable mRNAs- | back 38 usually code for housekeeping proteins |
front 39 What sequence found in the 3' untranslated region (UTR) is a signal for degradation? | back 39 AUUUA |
front 40 The more times AUUUA is present the- | back 40 shorter the lifespan of mRNA |