Transciption Flashcards
Where in eukaryotic cells is DNA found
In the nucleus
Where in the cell does transcription take place
In the nucleous
What cells undergo transcription
Eukaryotic Animal Plant Fungi Protista
What polymer is synthesized during transcription
Pre mRNA
What monomers are used to construct this polymer and where are they found
Fee RNA nucleotides found within the nucleus or necleoplams
What enzyme is required for transcription
RNA polymerase
What is the pair pair for a DNA strand matching a rna strand
DNA- c-g a-t
RNA t-a a-u
Compare the abuse pair rule with that of 2 DNA strands
DNA does not contain uracil so T matches with A in DNA but a DNA/ rna match T bonds with A and A bonds with U
Which strand of the DNA contains the blueprint for the pre-mRNA
The template strand
In which direction is the DNA molecule read
3’ to 5’
The DNA strand and pre mRNA strand are
anti-parallel
in which direction is the pre- mRNA molecule constructed
5’ to 3’
Before printing presses were available books had to be transcribed in order to share information in them. Consider the definition of transcription and explain why the process in model 1 is described using that word
transcribe is to make an exact copy. transcription is making a copy of the information in DNA as RNA
What parts make up the transcription initiation complex
RNA polymerase and transcription factors
Where on the DNA strand does the transcription initiation complex form
prometer
Nearly all cells in an organism contain identical DNA and Each DNA strand may contain hundreds or thousands of individual genes. Is it likely that a cell would transcribe all the genes within its nucleus simultaneously
no, cells only transcribe genes as they are needed to make specific proteins
considering many types of cells in a multicellular organism, and their different functions, is it likely that all cells transcribe all their genes at some point in their life time
No, certain genes will be switched on in specific cells and switched off in others depending on the location and function of the cell
What has been removed from the pre- mRNA to make it into mRNA
Introns
What has been added to the mRNA that was not present in the pre-mRNA and where on the mRNA strand are the additional items located
a methyl cap to the 5’ end
a poly-A tail to the 3’ end
identify the structure through which the mRNA leaves the nuclous
the nuclear pore
the nucleotides on the mRNA will read in the next step to producing a polypeptide. what sequence of bases indicated the starting point for the polypeptide bleuprint
AUG
the ‘m’ in mRNA is short for messenger. why is this molecule called messenger RNA
m RNA molecule carries the code for the polypeptide from the nucleus to the cytoplasm (or ribosome). so its like a messenger
the human genome contains about 25,000 genes and yet produces about 100,000 different polypeptides. how is this possible
a single sequence of pre-mRNA can produce different mRNA sequences depending on what introns are removed
what is the advantage of the poly-A tail added to the 3’ end of the mRNA
it prevents the information- carrying part of the mRNA from being destroyed by the exonucleases before the polypeptide can be formed
why are some poly-A tails longer than others
an mRNA with a short tail will have a shorter lifespan. proteins are needed over long periods of time might come from lone tail in mRNA whereas proteins only needed briefly may come from short tails
summarize the steps of trasnciption
pre-mRNA is made from the template strand of DNA starting at the prometer by transcription initiation complex (RNA polymerase and transcription factors). When the RNA polymerase reaches the terminator, the pre-mRNA is released. Introns are removed and the methyl cap and ploy-A tail are added to make mRNA
what type of biological molecule is an exonuclease
enzyme (protein)
free nucleotides must be available in a cells nucleus to produce mRNA strands. Where do these free nucleotides come from
the cytoplasm where older mRNA have been hydrolyzed by exonucleases
how might biologists use transcription mechanisms to support the theory of evolution
They could use the fact that all species use the same nucleotides in their DNA and mRNA. all species use prometer region to initiate transcription. All species use similar RNA polymerase enzyme. SLight variations in the mechanisms could help connect species in an evolutionary phylogenic tree or cladogram
purpose
produces an RNA copy of a gene. To make proteins for our body to keep going.
definition
The use of a gene sequence to make a copy of RNA
products
mRNA to make proteins (transfer, ribosomle, filler
product processing
5’ to 3’
antiparallel
5’ compliment is 3’
base pairings
A-U C-G
codons
every 3 base pairs is a codon
A-U
end result
RNA
main enzyme
RNA polymerase
location
nucleus
when the RNA polymerase reaches the ___sequence of the base pairs on the DNA template strand, it completes the production of pre-mRNA and releases it into the nucleoplasm
terminator
The portions of the pre-mRNA that remain are called
exons
Once the cytoplasm the mRNA will be subject to __ exonucleases that immediately start removing individual nucleotides from the 3’ end of a nucleic acid
exonucleases
