If DNA’s shape is altered it can’t function properly. RNA is more flexible so changing the shape changes the function, which is wanted. Any shape of RNA can become another. Three shapes/functions of RNA:
-mRNA: messenger (linear_____)
-rRNA: ribosomal (large and like a globe) More stable than mRNA.
-tRNA: transfer (shaped like t) If you flatten this it becomes mRNA.
Hydrogen Bonds ……………………………….
Protein Synthesis Overview- Two Processes:
Transcription- synthesis of mRNA under the directions of DNA
Translation- is the actual decoding of the mRNA into a polypeptide. Occurs in ribosome’s of cytoplasm and rough ER. (Ribosome’s don’t do anything but house).
---To make proteins we reassemble proteins found in meats, beans, fish, nuts, ect;
Triplet Code: codon- a series of three base pairs that code for an amino acid.
DNA polymerase adds bases and knows when to stop when it hits the terminator. The direction DNA replicates is 3’ (antisense strand) to 5’ (sense strand) on parent and 5’ to 3’ on new. RNA processing is like an editor. Exons are the regions of mRNA that are kept (codons). Introns are what is unneeded so are removed; they don’t make proteins. Caps and Tails are protection; they are like helmets and shoes.
DNApre-RNARNA processingRNA mRNA is made in the nucleus during pre-mRNA
AUG is the start codon; Stop codons: UAU, UAA, UGA.
Mutation Notes
Mutation- is a permanent change in organism’s nucleic acids (DNA/RNA). They can be results of mistakes in replication or transcription. Mutagens are chemicals that result in mutations (smoking, UV radiation)
Two levels of Mutations: chromosomal level and point level.
Chromosomal Level: Large mutations involving the entire chromosome (or large sections of them) and are almost never beneficial. Four types: * Duplication- Parts of a chromosome are made too many times * Translocation- Two non-homologous chromosomes swap information. (Eye color and height