Tutor profile: Ana S.
What are the four major classes of biological macromolecules and their corresponding monomers?
Proteins - Amino Acids Carbohydrates - Monosacchrides Nucleic Acids - Nucleotides Lipids - Fatty Acids
Subject: Basic Chemistry
Please name and list the five bond types in order of strongest to weakest. Explain.
Ionic, Covalent Hydrogen, Dipole-Dipole, and finally Van der Waals forces. Bond strength is determined by the stability of the state for which the bond will provide. Ionic bonds occur when molecules with a positive or negative charge (termed ions), are attracted to each other and bond to form a new substance. A great example of this is salt (NaCl)! These bonds are formed through electrostatic attraction, and provide a stable charge to both molecules involved in the bond. A close second is covalent bonds. These bonds are created when atoms share electrons, bringing them to a more stable state. Just like with ionic bonds, because of the stability they provide for both atoms involved in the bond, they are incredibly difficult to break. Hydrogen bonds/Dipole-Dipole (DD) interactions form when there is a large difference in electronegativity between two atoms joined by a covalent bond, creating an unequal sharing of electrons and pulling the electrons in one way or the other. While hydrogen bonds are stronger than other DD bonds, both are weaker than ionic and covalent bonds, as they are less stable! Finally Van der Waals forces are the weakest, as they represent weak residual attraction between one molecule to the electrons of the other.
Describe the Central Dogma of Biology (the cellular processes involved in converting DNA to RNA to a protein). Use relevant nomenclature as necessary.
The Central Dogma of Biology is the scientific fact that cell information is processed as DNA to RNA and finally to protein. To go from DNA to RNA, the cell must undergo a process called transcription, which occurs in the nucleus. Transcription is the process by which DNA is copied (transcribed) as a more "readable" format for the cell machinery. To do so, transcription machinery known as RNA polymerase enzymes are used to unwind the DNA and, nucleotide by nucleotide, build a strand of mRNA which complements the original template DNA sequence. The mRNA formed during transcription is then transported out of the nucleus into the cytoplasm with a final destination of the ribosome, which essentially the "protein building factory". Once there, mRNA goes through a second transformation to become a protein in a process termed translation. It is in the ribosome that mRNA codes are read and converted to proteins, in a similar fashion to translating a language. Sequences of 3 base pairs, termed codons, are read and an amino acid which corresponds to those 3 base pairs is attached, converting the mRNA to protein. Once it is signaled that all of the necessary amino acids to form the protein are attached (as signaled by a STOP codon, a 3 base pair sequence which is not converted to any amino acid), the protein synthesis process is halted, allowing for post-translational changes of the protein to begin. This ends the processes involved in The Central Dogma of Biology.
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