Genetics first Flashcards
1
Q
Describe the RNA world hypothesis
A
Idea that RNA can work as a catalyst and pass genetic information
2
Q
What 3 types of ribosomes support the RNA world hypothesis?
A
- RNA Ribozymes promote key reactions
- Riboswitches turn genes on and off
- Coenzymes promote the citric acid cycle
3
Q
What are the 3 key ssumptions of an RNA world?
A
- RNA at one time stored genetic information
- RNA replication follows the same rules as DNA replication
- Ancient RNA provided the same catalytic roles as proteins
4
Q
Give a pro and a con of the RNA world hypothesis
A
Pro: RNA is ancient and found in everything
Con: RNA is complex and would not have formed randomly
5
Q
Give 2 examples of possible pre-RNAs
A
- Therose Nucleic Acid (TNA) uses 4-C therose, which is more likely from the prebiotic soup however has not yet been synthesized abiotically
- Peptide Nucleic Acid (PNA) has RNA bound bases bond on an amino acid backbone. Amino acids are easier to produce
6
Q
What is the major flaw of the PNA/TNA world hypothesis?
A
Neither sugars nor amino acids self-organise
7
Q
How could PAHs play a role in the construction of RNA?
A
- PAHs are abundant in pre-biotic molecules an have the ability to self organise and stack
- Hypothesized that they could bind to small flat molecules, building up chains of RNA
- Spacing between PAH’s is 0.34 billionths of a metere, exactly the dame spacing as between bases in RNA
HOWEVER: not tested yet and hard to get
8
Q
Who made a self-replicating DNA molecule and what was it made of?
A
Guenter von Kiedrowski
six nucleotide sequence CCGCGG (had to be fed fresh C and G)
9
Q
What recent problem has arisen for the RNA world hypothesis?
A
- Believed that RNA nucleotides would have mixed with DNA backbones creating “heterogenuous” strands, and that these ‘chimeras’ were an intermediate step
- However, research has shown that these arrangements are unstable so did DNA and RNA arise in tandem?
