Nucleic Acids and the Origin of Life Flashcards
Nucleic acids?
polymers specialized for the storage, transmission, and use of genetic information
DNA and RNA full forms?
DNA = deoxyribonucleic acid
RNA = ribonucleic acid
Parts of a nucleotide?
Nitrogenous base, phosphate group, sugar (ribose or deoxyribose)
Triphosphates (ex. ATP)?
Store chemical energy in the form of three phosphate groups
The 4 different Nitrogenous bases/DNA bases?
Adenine, Guanine, Thymine, Cytosine (Uracil - in RNA)
Purines?
Double ring structures; Adenine and Guanine
Pyrimidines?
Single ring structures; Thymine, Cytosine and Uracil (in RNA)
Chemical difference between DNA and RNA
Presence of Uracil instead of Thymine in RNA
Bonds in DNA and RNA?
Phosphodiester bonds
How do purines pair with pyrimidines?
Through Hydrogen bonds
Complementary Base Pairing?
A–T
C–G
Difference between DNA and RNA?
RNA: Presence of Uracil; single stranded
DNA: Presence of Thymine; double stranded
What type of helix does DNA typically form?
right-handed double helix (B-form DNA)
Depending on conditions, DNA can form Z-form and A-form helices as well.
Grooves in DNA?
Due to the angle of the purines, the B-form helix has major and minor grooves.
DNA is a _______ molecule
informational
Central Dogma for Molecular Biology
DNA replication —> Transcription —> Translation
Complete set of DNA in living Organisms
Genome
Sequences of DNA that encode specific proteins
Genes
Sources of Biological molecules?
- Outer Space
- Geophysical means (Earth origin)
Chemical Evolution?
Conditions on primitive Earth led to formation of simple molecules (prebiotic synthesis); these molecules led to formation of life forms.
Miller and Urey’s experiment?
Experiment with gases thought to have been present in Earth’s early atmosphere.
An electric spark simulated lightning as a source of energy to drive chemical reactions.
After several days, amino acids, purines, and pyrimidines were formed.
What is thought to have evolved first?
RNA; Catalyzed its own replication and protein synthesis
Riboenzymes?
Folded RNA molecules that can act as catalysts.
They can catalyze reactions on their own nucleotides as well as other molecules.
Can metabolism and replication occur in dilute aqueous environments?
No; The compounds involved must have been concentrated in a compartment.
How are living cells separated from their environment?
Living cells are separated from their environment by a membrane.
Coenzymes?
‘e- taxis’ that transfer
electrons from one reaction
to another. Ex. NAD+ and FAD
ATP?
Adenosine Triphosphate; Transfers energy from one reaction to another within cells
