Week 4-7 Flashcards
What are operons
A group of structural genes plus sequences that control transcription
True or false some viruses can copy rna from rna
Yes they can undergo rna replication
What are the only 3 RNAs that are in both eukaryotes and prokaryotes
mRNA
rRNA
tRNA
What are the 6 types of RNAs that are found in eukaryotes only
Pre mRNA
SnRNA
SnoRNA
microRNA
Small interfering rna siRNA
Pwiwpinteracting rna piRNA
The type of rna that only prokaryotes make during transcription
CRISPR RNA
What are the structural and functional components of ribosomes
Ribosomal rna
Which rna polymerase helps to destroy transposable elements in the reproductive cells
Piwi rna
Which rna polymerase assists in the destruction of FOREIGN DNA
CRISPR RNA
Which rna polymerase plays a role in rRNA processing
Small NUCLEOLAR RNA
Which rna polymerase plays a role MRNA processing by forming part of the spliceosome
Small NUCLEAR RNA
Which rna polymerase assists in the destruction of other rna molecules
Small INTERFERING rna
What is the site of initiation of transcription
The promoter
Whats the purpose of adding the 5’ cap
Protection
Helps the ribosome to bind to the 5’ end of the mRNA
Helps in export
Stabilises the mRNA
What are the two functions of dna methyl transferases
Helps bind methyl to dna
Recruits HDAC’s to tighten the chromatin structure
Name the two ways in which dna methylation can come about
De novo DNA methylation (during early development )
Through inheriting dna methylation patterns during cell division
Whats the purpose of 3’ cleavage and the addition of poly A tail
Stabilises mRNA
Helps ribosomes to bind to mRNA
Whats the purpose of rna splicing
Removes the non coding introns and joins exons
Allows us to form a lot of proteins with a single gene via ALTERNATIVE SPLICING
What has to occur before you can add the adenine nucleotides during polyadenylation
The pre mRNA has to be cleaved at the 3’ cleavage site which is downstream the consensus sequence
What has to occur before the 5’ guanine nucleotide is added
One phosphate of the first nucleotide has to be removed at the 5’ end
What does the new guanine nucleotide become after methylation
7- methyl guano sine
Name the 3 different types of sites that are present during splicing
Splice donor site
Branch site
Splice acceptor site
The steps of splicing in order of occurrence
Capping
Cleavage
Polyadenlation
Splicing
Export
DEFINE ALTERNATIVE SPLICING
When you create multiple mRNAs from one gene by linking different combinations of exons and thus making many different proteins
Give an example of hat could happen if the slice sites are mutated
If slice sites are mutated its could lead to the production of a non functional or harmful protein being formed
An example is seen in the alternative splicing of MYOSTATIN, the normal alternative splicing product is a functional myostatin protein that stops muscle growth however if its mutated leads to the formation of a NON FUNCTIONAL PROTEIN that leads to MUSCLE HYPERTROPHY where muscles don’t stop growing
The direction in which the polypeptide chain is made during translation
From the amino side to the carboxylic side
How many protein factors are involved in the initiation of transcription in prokaryotes and eukaryotes respectively
3 and about 12
In prokaryotes what helps the ribosome to position itself correctly to the mRNA
The shine dalgarno sequence
In eukaryotes what helps the ribosome to position itself correctly on the mRNA
The 5’ cap / 7- methylguanosine
In eukaryotes what helps the ribosome recognise the Start codon
The kozak sequence
What amino acid does AUG code for in prokaryotes and eukaryotes respectively during translation
N-formylmethionine and methionine
How many release factors are there in prokaryotes during termination
3
What does each one recognise or bind to?
RF 1- recognises UAA & UAG
RF2 - recognise UAA & UGA
RF3- removes RF1 and RF2
How many release factors are in eukaryotic translation termination
2
What are their names and functions
eRF-1 : recognises all 3 stop codons
eRF-2 : removes the polypeptide chain from ribosome
Which enzyme catalyses the nucleophillic attack by the 3-OH at the primer end terminal on the alpha phosphate of the incoming dNTP that is based paired with the template
DNA polymerase (this is dna replication )
Which 3 proteins are common in both during dna replication
Helicase
SSB
DNA ligase
