Transcription --> DNA to RNA Flashcards
x-rays can cause mutations in ……
genes
What did alkaptonuria cause?
In urine turning black
One gene codes for one ……….
polypeptide (protein)
“Arg mutants” had a mutation in ….
one of the genes that code for the enzymes responsible for the multistep process of creating arginine.
What is the promoter site?
A short sequence of DNA
What does genetic code include?
4 possible nucleotides. RNA has uracil in place of thymine.
20 Amino acids
What is the wobble effect?
The flexibility in pairing, the third base in a codon can pair with more than one base in the anticodon
The genetic code is read continuously, as the insertion or deletion of single nucleotide or a pair of nucleotides cause a certain …….
viral protein to not be produced.
What is the purpose of transcription?
To copy a section of DNA that represents a gene so that it can be used by a ribosome to read it and make a protein.
List three points about the genetic code.
- It is redundant as 64 possibilities for 20 amino acids.
- The genetic code is continuous, meaning there are no spaces between codons. The addition/removal of a single nucleotide causes a frameshift mutation.
- The genetic code is universal amongst all living organisms. A codon codes for the same amino acid in humans as in bacteria.
What is the start codon and also codes for the amino acid, Methionine?
AUG
Genetic code is written in regards to RNA from the…
5’ to the 3’end
Every polypeptide starts with
MET
The 3rd nucleotide in a codon can differ while still coding for the same amino acid. What effect is this?
“wobble effect”
There are __ stop codons that tells TRANSLATION to stop.
3
Transcription takes place in the…
nucleus
Three key steps of transcription?
- Initiation
- Elongation
- Termination
The promoter region is high in what nitrogenous bases?
Adenine and Thymine
Why is the 5’ end capped at the beginning?
It is capped at the beginning to protect the mRNA strand from being degraded by certain enzymes (protection from enzymes).
In eukaryotic DNA, what is different for transcription?
In prokaryotic, there is a promotor region, however instead for eukaryotic, it is called the TATA box or also know as the TATAAA.
What are introns?
Longer sequences of nucleotides that are pretty much useless, and the one that is removed in the pre-mRNA strand as they do not code for anything.
How are introns removed?
Through RNA splicing.
What are exons?
Shorter sequences of nucleotides, used to synthesize proteins.
How many nucleotides are exposed during the second step of transcription, elongation?
10 nucleotides
RNA polymerase works in the 5’ to 3’ direction adding a new nucleotide to the ______ of previous nucleotide.
3’-OH
Why is RNA polymerase faster than DNA polymerase in DNA replication?
RNA polymerase have no proofreading capabilities therefore they work much faster than DNA polymerases that complete DNA replication.
Multiple RNA polymerases can be working on the same gene, why?
Multiple RNA polymerases can be working on the same gene at the same time as each one is only occupying a small portion of the gene. Allow for many mRNAs to be created of the same gene quickly.
What enzyme cuts out the introns?
Spliceosomes
Spliceosomes are a combination of what?
combination of protein and snRNA
What is snRNA?
The snRNA is another form of RNA, called snRNPs “snurps”
What does snRNPS do?
allows the spliceosome to recognize specific mRNA sequences.
What are the protein variants called?
isoforms
What do the protein variants have?
Different cellular functions or properties
What is alternative splicing?
It occurs by rearranging the pattern of intron and exon elements that are joined by splicing to alter the mRNA coding sequence
Template strand is
antisense
coding strand is
sense
