RNA world Flashcards
What is the central dogma of gene expression?
DNA-RNA-Proteins
What does the RNA world hypothesis suggest about the relationship between RNA and DNA?
RNA likely predates DNA
What conditions are thought to have enabled the chemistry necessary for the RNA world?
A stable hydrosphere
What are ribozymes?
RNA molecules that can act as enzymes
What are some precursors from which RNA can be synthesized?
- NH2CHO
- Ribose from formaldehyde
- Bases from cyanide (HCN)
- Phosphate from common minerals
What feature of RNA allows it to accept and donate H bonds?
2’OH
What types of structures can RNA fold into?
- Primary (chain structures)
- Secondary (e.g. tRNA)
- Tertiary
How does RNA’s solubility in water compare to DNA’s?
RNA unfolds in water as it has limited hydrophobic components, while DNA is not as soluble
What characteristic of RNA allows it to mutate and evolve?
Error-prone replication processes
How does RNA play in storing information?
Through the RNA sequence
What environmental factors can affect RNA’s behavior?
- Temperature
- pH
- Salinity
What is a riboswitch?
A segment of RNA that can change its structure in response to environmental changes
What is the function of hammerhead ribozymes?
They cleave RNAs at certain sequences
What evidence supports the idea that RNA could self-replicate?
Self-replication is likely but yet to be observed
Evidence of the RNA world
Relics can be used instead as seen in cofactors, with many posessing adenosine (FAD, NAD, CoA etc..)
What is a common co-factor that suggests RNA predates certain enzymes?
Adenosine
What evidence suggests that the peptidyl transferase center is a ribozyme?
It forms peptide bonds between amino acids
What is the role of proteins in relation to nucleic acid-directed protein synthesis in the RNA world?
They are of peripheral functional importance
Features of RNA as a living molecule
Stores information
Senses and responds to environmental changes through forming different H-bonds in response to temp, pH, salinity, also acts as a riboswitch
Likely can self replicate, though unobserved
Catalytic properties
