BIOM-360 Lecture Notes - Lecture 22: Messenger Rna, Reverse Transcriptase, Ionic Bonding
2 May 2018
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The Flow of Genetic Information
New DNA and RNA molecules can be made from already existing molecules via
polymerases.
Genes encoded in DNA are transcribed into mRNA, tRNA, or rRNA by RNA
polymerase.
RNA sequences can be reverse-transcribed back into DNA by reverse
transcriptase.
mRNA is translated into polymers composed of AA monomers connected via
peptide (amine) bonds.
Proteins cannot be reverse-translated to nucleic acid.
Functional RNA vs. mRNA
mRNA (messenger RNA) carries the message for protein synthesis.
The recipe.
rRNA (ribosomal RNA) are the components that are located in the ribosome that will help build the
building blocks in the ribosome.
The building blocks.
tRNA (transfer RNA) carries AAs for protein synthesis.
Responsible for transport.
Protein Structure
AA structure
Central Carbon
C-terminal (carboxyl group)
N-terminal (amino group)
Contains Nitrogen
Side chain
*If proteins didn’t fold, and everything were linear and laid out, living organisms would be massive.
Polymers of AAs linked by peptide bonds.
AAs can be polar, nonpolar, or charged, depending on nature of side chain.
Polar, Nonpolar, and Ionic
The Difference
Ionic bond → transfer of electrons from a metal to a nonmetal
No metal in DNA
Covalent bond → sharing of electrons between nonmetals.
Equal sharing = nonpolar
Unequal sharing = polar
DNA Replication
Super coiled double helix that needs to be unwound in an orderly fashion.
Complex process involving numerous proteins which help ensure accuracy.
The 2 strands separate, each serving as a template for synthesis of a complementary strand.
Synthesis = semi-conservative.
Each daughter cell obtains one old and one new strand.
Origin of replication
Replication fork is the spot where the helix/DNA starts being copied (split).
Document Summary
New dna and rna molecules can be made from already existing molecules via polymerases. Genes encoded in dna are transcribed into mrna, trna, or rrna by rna polymerase. Rna sequences can be reverse-transcribed back into dna by reverse transcriptase. mrna is translated into polymers composed of aa monomers connected via peptide (amine) bonds. Functional rna vs. mrna mrna (messenger rna) carries the message for protein synthesis. The recipe. rrna (ribosomal rna) are the components that are located in the ribosome that will help build the building blocks in the ribosome. The building blocks. trna (transfer rna) carries aas for protein synthesis. *if proteins didn"t fold, and everything were linear and laid out, living organisms would be massive. Aas can be polar, nonpolar, or charged, depending on nature of side chain. Ionic bond transfer of electrons from a metal to a nonmetal. Covalent bond sharing of electrons between nonmetals.
