BIOL215: Unit 1

• Hydrogen bonds are weak electrostatic attractions between the partially positive end of one polar covalent bond and the partially negative end of another.
• Nucleotides are subunits of nucleic acids
• There are three parts of a nucleotide: the phosphate group, the 5-carbon sugar and the "nitrogenous" base
• The phosphate group contains of the phosphate aton.
• The 5-carbon sugar molecule is a carbon skeleton that contains oxygen and hydrogen to form C double bond O, C single bond H, and C single OH.
• The nitrogenous base consists of carbon and nitrogen atoms bonded to form ring structures. Some only have one ring (pyrimidines) and others have two rings (purines). Both rings act as bases because they pick up protons in water.
• To form the chain of nucleotides that make a nucleic acid, a covalent bond has to form the phosphate group of one nucleotide with the sugar of another.
• A monomer is a small molecule that can be linked via covalent bonds to others to form the larger macromolecules called polymers.
• Nucleotides are monomers and nucleic acids are polymers.
• Nucleic acids are polar. One end of the nucleic acid is different than the other. One phosphate group on the end, linked to a 5' carbon, and an OH group to the other, linked to a 3' carbon.
• Primary Structure refers to the sequence of nucleotides in a nucleic acid.
• There are four nucleotide bases: cytosine, thymine, adenine, and guanine.
• Nitrogenous bases stick out from the backbone.
• RNA is extremely similar to DNA but there are two key differences: 1) U's not T's and 2) Ribose not Deoxyribose.
• There is a hydroxide on the 2' end of ribose but an H on the 2' end of deoxyribose. "Deoxy" refers to "off-oxygen".
• DNA Secondary Structure refers to two individual DNA strands can interact if three things happen: 1. the strands line up in the opposite 5' to 3' direction polarity ("antiparallel fashion"), 2. each G on strand is directly opposite from the C strand and lastly, 3. each T on strand is directly opposite from the A strand.
• Hydrogen Bonding Function: due to strong electronegativities, the N and O atoms carry negative charges while the H carries a positive charge
• RNA Secondary Structures generally exist as single-stranded molecules but can form double helices.
• RNA Secondary Structures happen when a single strand of RNA folds back on itself such that sections become in an antiparallel fashion.
• Just like DNA, stem-and-loop forms secondary structure.
• Teritiary structure also exists.
• The C-OH group of the 2' carbon of a ribonucleotide can participate in a lot more reactions than the C-H group on the 2' carbon of a deoxyribonucleotide.
• The difference in structure, along with the hydrogen bonding that occurs along the entire length of the DNA double helix, makes DNA much more stable and better for storing genetic information.
• DNA just sits there until the genetic information stored is coded and is created into an mRNA copy. RNA has groups of atoms that can participate in chemical reactions and can form different shapes.
• Water is made up of three atoms: two hydrogens and one oxygen
• The nucleus contains positively charged protons and also contains neurons
• A molecule of water consists of two hydrogen atoms attached to an oxygen atom by strong covalent bonds
• For every proton in the nucleus, there is a negatively charged electron
• There is no charge overall in the nucleus.
• Atoms can bond with each other. Unpaired electrons from two different atoms can pair with each other via a covalent bond and then a molecule forms.
• Electronegativity is the ability of an atom to attract the pair of electrons in a covalent bond
• The electrons in water's covalent bonds are pulled much harder by the oxygen nucleus than hydrogen nucleus
• Oxygen's electronegativity is much higher than nitrogen's, which is higher than carbon's and hydrogen's
• Water can form hydrogen bonds with oxygen or nitrogen atoms in any molecule.
• Most O's and N's are found in the DNA, RNA, and other parts of the body and the hydrogen keeps those molecules suspended in water.
• Water's a good solvent because it's polar and bent.
• The process responsible for making an mRNA version of the information in a gene is called transcription.
• The process responsible for making a protein from an RNA message is called translation.
• A gene is a segment of DNA that contains the information required to make a product with some function in the cell. Transcription is the process of making an RNA version of this information. During transcription, the sequence of bases in the gene acts as a template for the synthesis of an RNA molecule in the 5′ to 3′ direction.
• More specifically, a molecular machine called RNA polymerase binds to DNA at the start of gene. The polymerase then catalyzes the formation of phosphodiester bonds between ribonucleotides that are complementary to the deoxyribonucleotides in the gene.