AB

STARTER FOR CELLS AND GENOMES

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Cell – the basic structural and functional unit of all living things.

Genome – the set of hereditary information encoded in the DNA of an organism, including both protein-coding & non-protein coding sequences.

Gene – A DNA sequence coding for a single polypeptide.  The fundamental physical unit of heredity w/c occupies a specific chromosomal locus.

3 primary branches of the tree of life

  1. Prokaryotes- e coli
  2. Eukaryotes- 
  3. Archaebacteria- extremely high conditions

Mus musculus= mice

Human and mice have similar genes and development

Kit gene- same mutation with mice, pigment cells

Arabidopsis thaliana- grown indoors, large numbers

Drosophila melanogaster- proof of existence of gene

Polytene chromosome- giant chromosome, due to  many rounds of replication w/o cell division

Caenorhabditis elegans- hermaphroditic, short life span

Saccharomyyces cerivisiae- fungi, reproduce vegetatively or sexually, small genome

Danio rerio- transparent for first 2 weeks of its life

Xenpus laevisn- frog, vertebrate development

Mutations

  1. Intragenic mutation- gene is modified because of error during replication
  2. Gene duplication- give rise to families of related genes

**Once a gene has been duplicated, one of the 2 gene copies is free to mutate & become specialized to perform a different function w/in the same cell.**

  1.  DNA segment shuffling- 2 existing genes rejoin to become hybrid
  2. Horizontal transfer- DNA is transferred to genome of another cell, sometimes species

Orthologs- 2 separate species from same ancestral gene

Paralogs- related genes result of gene duplication, diff functions

Viruses- bacteriphages

  • Vectors for gene transfer

Horizontal gene transfer- responsible for penicillin-resistant gonorrhea

  • Sexual reproduction is example of horizontal gene transfer

Classification of functions

  1. Information processing
  2. Cellular processes and signaling
  3. Metabolism
  4. Poorly characterized

Mutation- alteration in DNA, source of new alleles

Conserved regions- unchanged subregions within the gene, most important

Human Genome Project- international scientific research project, goal is to determine sequence of human dna, mapping all genes of human genome

Translational medicine- a process in genetic findings are directly translated into new methods

Statin drugs- lowering LDL cholesterol (PCSK9 gene- controls LDL levels)

Familial hypercholesterolemia- high LDL cholesterol levels

PCSK9 protein binds to LDL receptors on liver cells, receptors return to cell surface and remove LDL

Cultivation of plants- 5000 bc

Animals were domesticated and selective breeding

Humors- body part that served as bearers of hereditary traits

Aristotle- vital heat from semen provided capacity to produce offspring

  • Vital heat cooked menstrual blood produced by females

THEORIES

  1. Theory of epigenesis (William Harvey)- organism develops from fertilized embryo to adult by developmental events
  2. Preformation theory- complete miniature adult, a homunculus
  3. Theory of Natural Selection (Charles Darwin)- populations more offspring than environment= struggle for survival= heritable traits to adapt
  4. The Chrosome Theory of Inheritance (Walter sutton and Theodore Boveri)- inherited traits are controlled by genes that reside in the chromosome transmitted through gametes for genetic continuity

Matthias Schleiden and Theodor Schwann- cell theory, all organisms are composed of cell from pre-existing cells

Louis Pasteur- disproved spontaneous generation

Charles Darwin- “origin of species”. Existing species arose by descent w/ modification from ancestral species

How a new species form- population is isolated, variations of inherited traits accumulate

Gregor Johann Mendel- general model of how traits are inherited

Carl Correns, Hugo de Vries, and Erich Tschermak- enlightened mendel’s work

Alleles- alternative forms of a gene

Mutant genes- used as markers, location of genes on chromosome

Why proteins as carriers of genetic information- proteins’ universal distribution

Avery, Macleod, and McCarty- DNA is carrier of genetic information

James Watsona nd Francis Crick- structure of DNA

Difference of DNA and RNA- contains different sugar in its nucleotides and uracil instead of thymine for nitrogenous base. RNA is single-stranded.

Enzymes- largest category of proteins, biological catalysts, lowering energy of activation

Proteins

  1. Hemoglobin- oxugen in RBCs
  2. Insulin- pancreatic hormone
  3. Collagen- connective tissue
  4. Actin and yosin- contractile muscle proteins

SICKLE CELL ANEMIA

  • Mutation in gene encoding B-globin causes amine acid substitution in 1 of 146 amino acids in the protein
  • Diagnosed patients have 2 mutant cells of beta-globin gene= sickle cell anemia
  • Mutant b-globin causes hemoglobin molecules to polymerize when oxygen is low
  • Easily break, block blood flow, pain and damage