Essay on Dna and Energy

Submitted By dahan786
Words: 2619
Pages: 11

BSCI 330 Notes
Lecture 1 * Cells are highly complex and organized * Cells are constructed from a hierarchy of molecular organization * Cells possess a genetic program * Organisms are built according to information stored in a collection of genes * Hereditary information defines a species * Genes * Store information * Blue prints for constructing cellular material * Directions for running cellular activities * Program for making more cells * The fundamental molecular mechanisms by which genetic programs are carried out are identical among all cell types. * All cells speak the same hereditary language * Cells transcribe their hereditary information by way of ‘Templated Polymerization’ * Proteins carry out the tasks specifies by DNA and are the workhorses of the cell * Central Dogma * Proteins carry out a cell’s activities * Proteins are widely varied in structure and function * Many proteins are catalysts * Cells use special classes of proteins as chemical catalysts (enzymes) * Cells are capable of producing more of themselves * Growth and Reproduction ultimately occur at the cellular level. * Genetic programs enable two classes of reproduction that either preserve identical copies of pre-existing cells or generate genetic change that lead to variations among individual cells * Cells are biochemical factories constantly acquiring and assimilating energy * Cells must accomplish this in a universes that favors disorder * Cells engage in mechanical activities * Motor proteins * All cells fall into one of two major categories, Eukaryotic and Prokaryotic cells. * Eukaryotic * 10 -100μm in diameter * Nucleus, organelles (subcellular compartments and macromolecular complexes), cytoskeleton * Highly structured internal organization * by definition, have a nucleus and other organelles bounded by internal membranes * evolved as a predator –engulfed other cells (>1 billion years ago), including prokaryotes, resulting in symbiotic relationships * Some prokaryote symbionts evolved into mitochondria, chloroplasts * As a result, eukaryotes have hybrid genomes * Eukaryotic genomes are large –20,000 genes and 10,000 times as much non-coding DNA * Long, drawn out, specific reproduction * Origin of mitochondria: Ancestral eukaryote ate (endocytosed) mitochondrial precursor. They took up residence. Many genes moved from mitochondrial to eukaryotic genome * Kleptoplasty: Sea slug Elysiasteals chloroplasts (“kleptoplasty”), and has also stolen some genes required to maintain them (horizontal transfer). * Model Eukaryotes * “Model organisms” have been chosen in which: * The genome has been sequenced * Site-directed and tissue-specific mutagenesis is possible * Expression of Multiple genes can be tracked across many cells simultaneously * The developmental sequence is known * Yeast -a minimal eukaryote * Arabidopsis (Common ThaleCress) * C. elegans–a nematode worm * Drosophila melanogaster -the fruitfly * Mouse

* Prokaryotic * 1 –5 μm in diameter * Lack distinct nucleus * Lack detailed internal organization * Evolutionary optimized for rapid and efficient reproduction * Most biochemically diverse among all organisms * Organotrophs: obtain energy by feeding on living things or organic material * Phototrophs :obtain energy by using sunlight to convert inorganic substances into organic material * Cyanobacteria * Formed the earliest fossil: stromatolites * Lithotrophs: obtain energy by