Lecture 33 Flashcards
What is LOH?
It is the loss or inactivation of a gene
What is an example of mitotic recom?
Where there is the production of two bad genes that lead retinoblastoma
What can lead to LOH?
Chromosome loss, deletion, unbalanced translocation, loss and reduplication, mitotic recomb, and point mutation
What is true about RNA?
it replaces thymine with uracil
What is chromosome crossover?
Where two homologous chromosomes crossover in the same place, break, and then reconnect but to the different end piece
What is transcription?
DNA copied and makes mRNA. One gene rather than a whole thing
What is true about RNA in eukaryotes and prokaryotes?
RNA does not need to be modified in prokaryotes, only eukaryotes
What are some modifications of RNA?
splice, the removal of introns(spliceosomes)
What are mRNAs?
intermediates that carry genetic information from DNA to the ribosomes
What are tRNAs?
adaptors between amino acids and the codons in mRNA
What are rRNAs?
structural and catalytic components of ribosomes
What are snRNAs?
structural components of
spliceosomes
What are miRNAs?
short single-stranded RNAs (20 to 22 bp) that block expression of complementary mRNAs
What are RNAi?
is similar to miRNA (RNA interference, double strand RNA, plant) siRNA (small interference).
What is the difference between RNA and DNA?
DNA=carbon sugar 2 H’
RNA= carbon sugar, 2 OH’
What type of molecule is RNA considered?
An intermediate molecule because it is found in the cytoplasm, could form double-helic, and bases encode genetic info
What happens if there is a lot of mRNA?
It leads to more proteins which is not wanted because it causes over-expression and damage
What needs to happens to mRNA?
it needs to be degraded
What does miRNA do?
non-coding to bind mRNA and induce degradation
What does RNA Pol do in prokaryotes?
Binds specific nucleotide sequences (promoter regions) plus transcriptional factors
What does miRNA?
It is super small and guide complex to RNA and block gene expression
How does RNA Pol know when to stop?
It has terminating sequences that tell it to stop
What does siRNA do?
result of viral infection and bind mRNA to induce degradation
What are the features of RNA Pol in prokaryotes?
It is a single RNA Pol
What is the holoenzyme made up of? What are the subunits?
5 subunits , 2 a, 1 B, 1 B’, o
What does the a subunit do?
initiates transcription and gets other proteins unwind
What does B do?
initiate relongation
What does B’ do?
bind to DNA
What does w do?
assemble enzymes
What does o do?
guides polymerase to promoter where it falls later
What is upstream?
negative portion of the coding sequence and 5’ area
What is downstream?
It is the 3’ and positive area
Consensus vs Conversed
Consensus: similar sequence but to identical
conserved: identical sequence
