Wednesday, November 14, 2007
Wednes-Day 2
Bio- we elucidated the sequence of events in translation beginning with the binding of mRNA to the ribosome. We then drew the tRNA approaching the mRNA followed by the hydrogen bonding attraction between the codon of the mRNA and the anticodon of the tRNA. A second tRNA molecule then joins its complementary mRNA codon at the adjacent site of the mRNA molecule. The two amino acids then form a peptide bond via dehydration synthesis, which begins the formation of the polypeptide/protein. The first tRNA is then released and then the ribosome moves along the mRNA molecule to continue translating the rest of the molecule into a polypeptide chain. When the stop codon of the mRNA is reached by the ribosome, there is no complementary anticodon for a stop codon so the amino acid (polypeptide) chain is then complete and is released from the ribosome to quickly become a functional protein (enzyme, hormone, etc.).
We then discussed different types of mutations. The simplest mutation is a point mutation of a single base. In "substitution", ene base can substitute for another, thus changing the DNA codon, which will cause a corresponding change in the mRNA codon that is transcribed, which MIGHT change the amino acid that is coded for.
There are other, single-base mutations: deletion and addition.
These point mutations are known as "frameshift mutations" because the addition or removal of a single base will alter the reading of the codon "triplets" drastically, as we demonstrated in class.
Tomorrow, we will discuss larger, chromosomal mutations.
Mutations are a source of the variety that we see within a species and between different organisms.
Chem 7/8- we did our part 1 multiple-choice quarterly today.
Grades should be posted by tomorrow.
We then introduced our new unit: Atomic Structure.
We reviewed our past knowledge of what particles comprise an atom, the relative masses and charges of those particles, and the locations of those particles in an atom.
We discussed the terms atom, ion, isotope, atomic number, and mass number. Regular use and application of these terms will help you remember them correctly.
Chem 9- we did our part 1 multiple-choice quarterly today.
Grades should be posted by tomorrow.
We then discussed different types of mutations. The simplest mutation is a point mutation of a single base. In "substitution", ene base can substitute for another, thus changing the DNA codon, which will cause a corresponding change in the mRNA codon that is transcribed, which MIGHT change the amino acid that is coded for.
There are other, single-base mutations: deletion and addition.
These point mutations are known as "frameshift mutations" because the addition or removal of a single base will alter the reading of the codon "triplets" drastically, as we demonstrated in class.
Tomorrow, we will discuss larger, chromosomal mutations.
Mutations are a source of the variety that we see within a species and between different organisms.
Chem 7/8- we did our part 1 multiple-choice quarterly today.
Grades should be posted by tomorrow.
We then introduced our new unit: Atomic Structure.
We reviewed our past knowledge of what particles comprise an atom, the relative masses and charges of those particles, and the locations of those particles in an atom.
We discussed the terms atom, ion, isotope, atomic number, and mass number. Regular use and application of these terms will help you remember them correctly.
Chem 9- we did our part 1 multiple-choice quarterly today.
Grades should be posted by tomorrow.
# posted by C @ 7:43 PM 
