gene transcription and micro Flashcards
(34 cards)
Heterochromatin=
euchromatin =
heterochromatin= dense, inactive
euchromatin= disperse, active
most proteins in chromatin are
histones
RNA differs from DNA in that it has
ribose instead of deoxyribose and uracil instead of thymine
What is the product of gene transcription?
mRNA
-carries the code for protein synthesis
can mRNA leave the nucleus?
Yes, to take DNA code to the ribosomes
Where are rRNA found
found on ribsomes
what carries amino acids that are used for protein sysnthesis in the ribosome?
tRNA
What are snRNA
-involved in transcriptional regulation and mRNA processing
-part of spliceosome machine
-first made of ribonucleotides, then folds into 3D structure
what is the exception to the central doga
some viruses
Central dogma: flow of information from DNA to RN
What is the genetic code
the dictionary that gives the correspondence between a sequence of nucleotide bases and a sequence of amino acids
3 nucleotides bases = codon
61 of 64 codons code for the 20 AA
3 stop codons
stop codons
UAA, UAG, UGA
start codon
AUG, methionine
In protein synthesis, in transcription, what is the first step
chromatin remodeling
breaking bonds of DNA
Allows for template strand to be exposed for RNA transcriptin
RNA polymerase II needs other proteins called transcription factors to be able to bind to the DNA. What is its name and what steps come after
TFIID
1. First bind TFIID to the TATA box
What is the promoter region
the promoter region is the region where basal transcriptional machinery attaches
The TATA box is on the promoter region and TFIID binds here first
What do enhancers do
increase transcription levels
responds to cell needs and stage of embryological development
activators attach to the _______ region to activate transcription of the region
enhancer
silencers
decrease transcriptional levels.
_______ attach to silencer region to inhibit transcription of the region
repressors
T/F Pol II can bind directly to DNA
False. TFIID needs to bind to TATA, only then Pol II can bind
Methods of post-transcriptional modification of (pre-)mRNA
- modify strand of pre mRNA after transcription (introns out, exons in)
- 7-mG methyl guanosine tail (protects mature mRNA from nuclease attck)
- Poly-A tail (keeps mRNA stable)
Why are introns important
important signaling sequences
Where does translation take place
at ribosomes
40 S small and 60S large which combine to form 80S ribsome.
each tRNA has an __________ loop complimentary to the codon on the mRNA
anti-codon
- the AA has to be activated with ATP via aminoacyl-trna synthetase so it can attach to correspondinf tRNA to become charged
