Beginning of Life and Synthetic Biology Flashcards
What did ‘fertile atmosphere’ experiments generate?
Amino acids
Bases - Adenine, Guanine, Uracil
ATP, Coenzyme A
Ribose
What can NH3 be made from?
(FeS) + N2 + H2O
What does HCN hydrolysis provide?
All of the nucleotides
What can aldehydes be made from?
CO2 and H2O
What are polyphosphates made from?
Meteor impacts in the oceans at 2000 degrees C
Why was primeval broth view experimentally criticised?
Too much H2
CH4, CO minor components
CO2 and N2 major components
‘Prebiotic soup’ - oceans - molecules too dilute to react
When was the RNA world predicted to be?
3.5-4 million years ago
What is the simple meaning of being living?
Anything that replicates is living
Which rRNA makes only RNA?
23S rRNA
What is special about the 23S RNA intron?
It splices itself out without any help from proteins
What does the 23S RNA intron need to splice itself out?
Free 3’ hydroxyl group of guanine nucleotide / nucleoside which attacks 5’ end of intron
What can the tetrahymena intron do?
1) Make and break bonds between tRNA and amino acid
2) Generate a poly-cytosine nucleotide strand, make and break phosphodiester bonds between nucleotides
What did Carl Woese find (1987)?
rRNA genes more conserved than ribosomal protein coding genes
What does rRNA provide and what does the protein provide?
The catalytic component for protein elongation, proteins provide scaffold
What does montmorrillonite clay do?
Attracts nucleotides promoting polynucleotide formation even in dilute solutions
Promotes vesicle assembly - membranes and encapsulation
What does RNA need to replicate?
One ribozyme, plus one complementary copy to act as a template
Why are errors in copying necessary?
For evolution to take place
What stabilises replicase RNA?
Amino acid (+ charge) - Selection for the first tRNA
What stabilises the RNA?
Amino acids - beginning of RNP world
What was the initial ‘tRNA’ function in?
Replication
What do many retroviruses have?
3’ tag with terminal CCA - signal for replication
What identifies a molecule as a substrate for replication and where does replication start?
3’ lops plus terminal CCA
Replication initiates at first C of CCA
What do stem loops do?
Provide catalytic potential
Provide dsRNA regions, so complimentary RNA strands formed
What is the ‘iron-sulphur world’ theory?
Metal sulphides (FeS) catalysed reactions to generate amino acids under high pressure and intense heat (up to 250 degrees)
What is carbonyl sulphide (COS) and what does it do?
Volcanic gas
In the presence of L-phenylalanine mediates the condensation to dipeptide. Mediates mixed peptide condensation with metal sulphides from single mixture of L, F, S, A, Y
What came first: translation or replication?
Translation
Why did RNA world give rise to DNA world?
DNA is more stable, better replicator
Which enzymes change RNA to DNA?
Ribonucleotide reductase: Ribose to deoxyribose
Reverse transcriptase: RNA to DNA
What are the three classes of ribonucleotide reductase?
Aerobic
Independent of O2 but cobalt-dependent
Anaerobic
