Transcription Flashcards
What is the central dogma?
The genetic instructions carried by the DNA must be transcribed into RNA and translated into protein
What process cause DNA to form RNA?
Transcription
What process cause RNA to form PROTEIN?
Translation
What is mRNAs?
Messenger RNA
What is the function of mRNAa?
code for protein
What is rRNAs?
Ribosomal RNA
What is the function of rRNAs?
Form basic structures of ribosome and catalyse protein synthesis
What is tRNAs?
Transfer RNA
What is the function of tRNAs?
Central to protein synthesis as adaptors between mRNA and amino acids
What is snRNAs?
Small nuclear RNA
What is the function of snRNAs?
function in a variety of nuclear processes, including splicing of pre-mRNA
What is snoRNAs?
Small nucleolar RNAs
What is the function of snoRNAs?
help to process and chemically modify rRNAs
What is miRNAs?
MicroRNAs
What is the function of miRNAs?
Regulate gene expression by blocking translation of specific mRNAs and cause their degradation
What is siRNAs?
Small interfering RNAs
What is the function of siRNAs?
Turn off gene expression by directing the degradation of selective mRNAs and the establishment of compact chromatin structures
What is piRNAs?
Piwi-interacting RNAs
What is the function of piRNAs?
Bind to kiwi proteins and protect the germ line from transposable elements
What is lncRNAs?
Long noncoding RNAs
What is the function of lncRNAs?
Serve as scaffolds as they regulate diverse cell processes including x-chromosome inactivation
What is trascriptome?
Set of all RNA molecules
What can RNAseq do?
Determine the sequence
What does transcription do?
Produces an RNA molecule that is complementary to one strand of DNA
How does RNA differ from DNA?
- RNA = ribose glucose whilst DNA = deoxyribose glucose
- RNA has uracil base unlike thymine in DNA
- RNA is less stable
- RNA is single stranded
Why is it important that DNA has thymine not uracil?
If uracil were used in DNA, cytosine deamination would be difficult to detect and repair
Which statement is true for DNA:
a) accurate, long term storage
b) transient
a is correct
Which statement is true for RNA:
a) accurate, long term storage
b) transient
b is correct
What is more stable RNA or DNA?
DNA
Can RNA act as a catalyst?
Yes
What is RNA polymerase?
Use a DNA strand as a template to join free nucleotides make a new RNA strand
What direction is RNA synthesised?
In a 5’ to 3’
What side the 5’ of a ribose attach to?
phosphate group
What side the 3’ of a ribose attach to?
hydroxyl group
What do you need for RNA synthesis?
- RNA polymerase
- DNA locally single strand
- Nucleotides (A/C/G/U)
- Phyrophosphate is lost
- 5’ to 3’ direction
What provides the energy required for polymerisation by formation of a phosphodiester bond?
Breakage of phosphonanhydride of nucleotide
Why is processing the ends of mRNA essential?
For stability
Describe the processing of the ends of mRNA?
- 5’ end of mRNA gets capped with an atypical nucleotide
- 3’ end of mRNA gets a tail of poly-A nucleotides
- Introns, non-coding sequence have to be removed
What is the process called when removing introns from pre-mRNA?
Splicing
What are exons?
Coding DNA
What are introns?
Non-coding DNA
What are introns sliced out by?
Spliceosome
What is a sliceosome?
ribonucleoprotein particles made form snRNAs that bind to proteins
What is alternative splicing?
More than one protein expressed from a single gene
How do mRNA leave the nucleus?
Through the nuclear pores
What RNAs are selectively exported from the nucleus?
Mature
What effects the half-life of the mRNA?
The sequence of the mRNA
What determines how many times an mRNA can be translated?
the stability of an mRNA
What can alternative splicing leads to?
Multiple different protein isoforms from a single gene
