Genes and proteins Flashcards
With what does he central dogma of molecular biology deal?
The detailed residue-by-residue transfer of sequential information.
What does the central dogma state?
Information cannot be transferred back from protein to protein or nucleic acid.
What is the genotype?
The genetic make-up of an individual.
What is the phenotype?
The physical traits.
Characteristics expressed by individual.
Why do regulatory systems and pathways interact?
To form complex networks.
What do complex networks add to most G-P maps?
Additional complexity.
Fr what does genotype code?
Phenotype.
What did George Beadle and Edward Tatum suggested in 1941?
Genes act through enzyme production.
Each gene is responsible to produce a single enzyme –> affects a single step in metabolic pathway.
How was the hypothesis of Beadle and Tatum characterised?
Oversimplification.
How is the reformulation of: ‘one gene-one polypeptide’ characterised?
Too simple to describe the relationship between genes and proteins.
What did Beadle and Tatum’s experiment found?
Mutations in each of the ‘transformational steps’ between precursor and final products n biosynthesis of arginine.
By what was each step in Beadle and Tatum’s experiment undertaken?
By an enzyme encoded by different DNA sections/genes.
By what can enzymes be formed?
Multiple protein subunits.
What can enzymes include?
Non-protein factors.
What do non-protein factors include?
RNA.
What can genes produce when they are processed in different ways?
Similar, different proteins.
Of what are eukaryote genes composed?
Exons.
Introns.
What do exons code for?
Polypeptide sections.
What do polypeptide sections make up?
The whole protein.
When does splicing occur?
After transcription.
Before translation.
What do differences in splicing alter?
Set of exons.
What do exons produce once they are translated?
The final protein.
What do variations in splicing effect?
Protein structure.
Protein function.
Where can modification of key translational controls like start and stop codons result for proteins?
Missing normal N-terminal.
Longer C-terminals.
What is the N-terminal of a protein?
Front section.
What are C-terminals of a protein?
End sections.
For which organism was in vitro transcription first demonstrated?
Escherichia coli RNA Polymerase.
Who did first demonstrate in vitro transcription for E. coli?
Sam Weiss.
Jerard Hurwitz.
Where could RNA Polymerase be visualised?
On DNA.
How could producing ‘tails’ of RNA by electron microscopy and transcription be followed?
By using 32P. NTPs.
A, C, G, U.
Of how many steps does transcription consist?
3.
What are the 3 stages of transcription?
- Initiation.
- Elongation.
- Termination.
What did analysis of various E. coli mutations found about the 3 steps of transcription?
Any stage could be interrupted to control gene expression.
Many antibiotics target one/more of stages.
By how many subunits is the Core Enzyme composed?
5.
Which are the 5 subunits the Core Enzyme is composed of?
- 2.
- α.
- β.
- β’ .
- ω.
What is the fifth subunit the Holoenzyme includes?
Sigma: σ.