Biology

DNA Transcription (Slide 20) The ?Central Dogma? - Crick 1958 DNA - RNA - Protein Proposed that this process could not go backwards The part of DNA that encodes for a protein (or RNA) is called a gene GENE: Functional unit of DNA that codes for one or more polypeptide chains or an RNA molecule Genome is not just genes, there are intervening sequences that don?t code for a protein Proteins are generated through transcription and translation How much protein is present can be regulated by the amount of transcription and/or translation Beta-catenine- high abundance in brain (A) but low abundance in muscle (B) DN A is transcribed by RNA polymerase One RNA polymerase in bacteria that does all the transcription CORE ENZYME: 2?, 1?, 1??

DNA Replication As the genetic information, DNA must be faithfully replicated and passed down to the next generation The structure of DNA immediately suggested a replication mechanism A strand of DNA can serve as a template for replication If you know one strand, you can determine the other What is the mechanism of replication? Meselson & Stahl used density centrifugation biomolecules will float or sink until they reach the point at which their density equals that of the gradient Meselson and Stahl?s results did not support the conservative replication model Using the same approach as Meselson and Stahl, how could you distinguish between these models? DNA replication initiates at Origins of Replication

Nucleic Acids, DNA Structure, and Chromosomes Nucleotides are the building blocks of nucleic acids One (NMP), two (NDP), three (NTP) phosphates 5 different bases: A, G, C (DNA and RNA), T (DNA), U (RNA) 2 different sugars: ribose (RNA), deoxyribose (DNA) Two kinds of 5-carbon sugars Five kinds of nitrogen containing bases The sugars and bases are linked through a glycosidic bond nucleoside = N-containing base linked to a 5 carbon sugar (no phosphate) nucleotide = N-containing base linked to a 5 carbon sugar & one or more phosphates Nucleotides are linked through phosphodiester bonds Link between nucleotides: 5? C of sugar - phosphate- 3? C of sugar (backbone) Variable portion: base

Protein Function and Enzymes Most proteins function by binding to other molecules Antibody - aggregating foreign Actin - binding to itself Enzymes Hexokinase - binding pocket for glucose, then catalyze Selectivity comes into play based on functional groups Proteins bind other molecules at the binding site Unique chemical environment Not only based on agreeing shape, but also non-covalent bonds In some cases this binding is very tight; in others it is weak and short lived. The binding site is a cavity on the surface created by several amino acids that interact with the substrate Chemical identity of function groups that dictates what molecules will bond Protein binding to another molecule is highly selective Thermal energy causes not matching molecules to dissociate

Bio 230: Cell Bio Intro to Cells: pg 1-26 Properties that define living organisms: Ability to reproduce on their own Viruses? Not living organisms but incapable of reproducing on their own Can grow and develop Require energy - metabolism Response to the environment Maintain homeostasis Contains genetic information (DNA or RNA) Composed of cells Cells are the fundamental unit of life. Invention of the light microscope led to the discovery of cells Robert Hooke Shortened telescope Many flaws, difficult to see Oil lamp with flask of water to illuminate specimen Examined cork - coined term cell Remains of cell walls after death Theodore Schwann All different species of animals were composed of cells Mathias Schleiden All different species of plants were composed of cells