Gene Expression Flashcards
What enzymes are involved in DNA replication?
DNA polymerase
Ligase
Helicase
What is the enzyme used in RNA transcription?
RNA polymerase
What is the template used in RNA transcription?
DNA strand
What are the 3 stages in RNA transcription?
Initiation
Elongation
Termination
What is the enzyme used in RNA translation?
Ribsome
What is the template used in RNA translation?
mRNA
How is the DNA strand being read in DNA replication? How is being made?
It’s being read 3’ to 5’ and being made 5’ to 3’.
When does termination occur in DNA replication?
When two replication forks meet.
Explain the initiation of RNA transcription.
A promoter recognises specific sequence on the DNA strand called the TATAAA-box.
In what direction is the DNA template during RNA transcription being read?
In 3’ to 5’. This means that the mRNA is complementary to the template strand and identical to the other strand.
The direction of how it is built is 5’ to 3’.
What is RNA processing?
pre-mRNA needs to become mature mRNA which is going to be translated.
What different steps are involved in RNA processing?
Capping
Tailing/Polyadenylation
Splicing
What is capping?
At the 5’ end there is put on a 5’ cap. This is to protect against degradation.
What is tailing or polyadenylation?
At the 3’ end there is polyadenylation tail. This is a lot of adenine put on.
This also protects against degradation.
What is splicing?
This happens in the middle where introns are removed. This step is sequence dependent and is necessary because introns are not supposed to be coded for in translation.
Are introns never translated in RNA translation?
Yes they can be if there is a mutation. Splicing is sequence dependent so it need precise splicing. If there is a mutation on an intron it might not be spliced off.
What kind of ribosomes are found in eukaryotes? What subunits?
80s ribosomes with 40S + 60S subunits.
How does initiation occur in translation?
First of the 40s subunit recognises the 5’Cap on the mRNA. It then starts to go through the mRNA. When it recognises the start codon AUG the 60s subunit is put on and the mRNA will start being read.
How does termination occur in translation?
By triplet codons as well called stop codons. UAA, UAG and UGA.
What is the wobble position of a tRNA and what does it do?
A base called in the wobble position is called wobble base. It allows the tRNA to recognise more than one codon.
In what direction do amino acids grow?
In N to C.
What is aminoacyl tRNA?
The tRNA that is needed for translation of the mRNA to produce an amino acid.
What is an anticodon?
A specific sequence found on the tRNA which matches/recognises the codon on the mRNA.
In what direction is the mRNA being read?
In 5’ to 3’.
How does elongation work in translation?
Formation of peptide bonds with the help of peptide transferase. The amine group and the carboxyl group join to form a peptide bond and H2O is released.
