Lecture 6 and 7 Flashcards
What is a narrow definition of genes?
A segment of DNA that has the instructions on how to make a protein
What is a wide definition of a gene?
A wider definition also includes RNA genes that generates RNA molecules as a final product
What is an exome?
The part of the DNA that will be transcribed into RNA
What is transcriptome?
All transcripts in that specific cell type
What is the 5-3 strand of the gene called?
The coding strand
And the 3-5
The lagging or the template strand
What are some structural differences between RNA and DNA?
In RNA there is ribose and and DNA deoxyribose and uracil in RNA instead of thymine found in DNA,
What is ncRNA?
It stands for non coding RNA and can be further divided into different categories. They have functions such as structural and functional.
How many RNA polymerase is there in humans and which is the most commonly used in cells?
3, and RNA polymease II is the most important one
What are the stop codons?
UAA, UAG an UGA
What are the start codons?
There is only one, AUG
What does it mean that the genetic code is redundant?
There are 64 possible combinations but only 20 amino acids so multiple combinations code for the same amino acid,
What does wobble base pairing mean?
That many amino acids has two specific nucleotides in the beginning and then the third can be whatever,
Describe the anatomy of the ribosome?
There is a large subunit with three binding sites E, P and A for tRNA and a small subunit with one binding site for mRNA
On a DNA strand how does the RNA polymerase know where to atatch?
There is on every DNA strand a promotor sequence where the RNA polymerase atatches
What happens when transcription is initiated by RNA polymerase?
RNA polymerase will seperate the strands and transcription will begin in a 5-3 directon from the template strand on the DNA.
How does the transcription stop?
There are multiple ways, the RNA polymerase can regocnise the terminator or the mRNA can bind to itself and the terminator to form a shape as a hairpin that interferes the RNA polymerase to move forward as well as other ways.
What happens after transcription?
There is now premRNA or primary mRNA that has to be spliced with spliceosome from introns so only the exons or the protein coding parts of the gene is left. There is also a 5’cap added to the 5 end of the mRNA strand that is a modfiedied guanisone and a 3’poly A tail to the 3 end.
Desrcribe in detail about the 5’cap and the 3’poly A tail
5’cap converts the 5’ end trhough a 4’ to 5’ linkage. 3’poly A tail is catalyzed by polyadenylate polymerase that aqdds adds adenosine monophostphates using adenosine tripohstphate as a substrate and built until around 250 nucleotides long.
What is the function of a 5’cap and a 3’poly A tail?
It protects against exonucleases which would degrade them, promotes ribosome binding, regulates nuclear export and the poly A tail also helps regulate transcription termination by interacting with the RNA polymerase. So the major function is to stabilize the mRNA.
What is RNA editing?
A pretty rare editing of the primary mRNA that inserts, deletes or substitutes nucleotides.
