DNA Dependent RNA Transcription Flashcards
Central Dogma in Simplest Form and when does it happen
Transcription Translation
DNA ——————> RNA —————-> Protein
Replication DNA--------------> DNA
-Happens during G1 and G2 stages
3 relationships between DNA, RNA, and Proteins
-Genes specify proteins or RNA products
-Pathway from gene to polypeptide involves transcription and translation
-Genetic code is written in three-letter words using a four letter alphabet (GCAT for DNA, GCAU for RNA)
Garrod experiment and when (4)
-1896
-studied Alkaptonuria
-causes developmental delay
-inborn error of metabolism
Beadle and Tatum what was studied and when
-1940
-Bread mold
-Suggested a gene produced a polypeptide
-x-rays produced a auxotroph
-Mutant had defective gene for enzyme needed to synthesize a particular nutrient
3 parts of a gene
promotor
transcription unit
terminator
promotor
-initiates transcription
-starts the sequence
-Like the signs going into a town telling you what’s coming
Transcription Unit
portion of gene that is copied into RNA
Terminator
Signals the end of transcription of a gene
Why is RNA created instead of DNA (4)
-Keeps DNA pristine and inside the Nucleus
-can be amplified
-regulation
-when you cut yourself RNA can copy itself quickly to help clot blood
mRNA
messenger
tRNA
transfer
rRNA
ribosomal
snRNA
small nuclear
miRNA
miniature
what is and why is it called the TATA box
promotor sequence that is made of lots of TA pairs
Transcription (3)
-polymerase works the same but RNA doesn’t require a primer
-Certain sequence of nucleotides says where to start and stop
-Before initiation transcription facotrs bind to the TATA box
stages of transcription
initiation
elongation
termination
Initiation of transcription
RNA polymerase binds to DNA and the double helix begins to unwind
Elongation of transcription
RNA polymerase adds RNA nucleotides in the same order as the DNA template
Termination of transcription
Enzyme and completed RNA release from the DNA template
What to prokaryotes have to do to start transcribing mRNA
have the coding region flanked by 5’ and 3’ untranslated regions
What to Eukaryotes have to do to start transcribing mRNA
-have the coding region flanked by 5’ and 3’ untranslated regions
-and add additional noncoding elements
Structure of mRNA
precursor mRNA
must be processed in nucleus to produce translatable mRNA
5’ cap
-where ribosomes attach to mRNA
-have a hook shape
Poly(A) tail
50-250 A nucleotides added tot eh 3’ end
-Protects mRNA from RNA digesting enzymes
What does every protein start with
AUG
Introns
-Non-protein-coding sequences in the pre-mRNA
-Removed before translation
-Alternative Splicing so different versions of mRNA can be produced
-Exon shuffling which generates new proteins
Exons
-Amino acid coding sequences in pre-mRNA
-Joined together in final mRNA
What do snRNPs do (4)
binds to introns
loop introns out of pre-mRNA
clip out introns
join exons
Alternative splicing
-Exons joined together to produce different mRNAs from the same gene
-Causes them to have different functions
What does translational initiation do
brings the ribosomal subunits, an mRNA, and the first aminoacyl-tRNA together
Where is mRNA translated into Protein (6)
-cytosol
-Ribosomes
-tRNAs
-Amino acids
-Translations factors
-ER
In DNA replication Helicase is an enzyme that
Separates 2 strands of DNA
Which is NOT true of DNA polymerase III
It synthesizes from 3’ to 5’
It synthesizes from 5’ to 3’
Synthesized DNA from 3’ to 5’
The Hershey and Chase experiment demonstrated that
DNA was the genetic material
In eukaryotic cells each chromosome has a single point of origin of replication
False
