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Cellular ReproductionA Brief History of Genetics Before Mendel
Major Discoveries Circa World War IHistory of Discovery of Cells
Evolution and Diversity of CellsArchitecture of Cells
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History of Genetics Before Mendel
Hippocrates (400 BC): traits are inherited from parents; reproductive products are obtained from all body parts and given to the offspring◦ Example: Macrocephali: species of humans w/ elongated head; Hippocrates
believed they styled their offspring’s head soon after birth Aristotle (350 BC): differed from Hippocrates due to the
inheritance of nails, hair, voice; did not believe it came from reproductive tissue because they were dead cells; based on the fact offspring sometimes resemble grandparents, he believed “reproductive material” was obtained from “nutrient substances” (semen from the father, originates from blood) designed specifically for a part; believed females had something that defined the “form of the embryo” ◦ Both Hippocrates & Aristotle believed trait inheritance was through reproductive
material Al-Jahiz (800s CE): proposed a theory of animal evolution through
natural selection (environmental effects) Abu Alkasem Al Zehrawi (Albucasis) (936 CE): described the genetic disorders in blood, now known as hemophilia • Otto Brunfels (1488-1534): adopted ancient classification of
plants, interested in medical advantages of botany, keep records of his plants, considered “link between ancient and modern botany”
History of Genetics Before Mendel
Hieronymus Brock (1498-1554): studied German plants, recorded them based on relation, resemblance, & medical use
Leonhart Fuchs (1501-1566): wrote book accurately classifying around 500 plants and their medical uses
Andrea Cesalpino (1524-1603): classified plants based on principles (fruits/seeds) not alphabetically or medical usage; established botany; believed plants were not sexual & divided plants by woody/herbaceous
Gaspard Bauhin (1560-1624): botanical classification, 6000 species of plants, classified between genus and species, “introduced binomial nomenclature system”◦ Species of plant receives a name of two terms: 1st is the genus, 2nd is the species
John Ray (1627-1705): classified 18000+ plants in a natural system (reflection of Divine Order); morphology (flowers, seeds…); monocots & dicots (classification of flowers), used term “species”
Joseph Pitton de Tournefort (1656-1708): classification of genera (structure of flower & fruit); didn’t believe in sexual reproduction of plants; used 2 word Latin name for plants; defined genus for future times (own classifications were often wrong)
Carl Linnaeus (1707-1778): defined the princples for natural genera & species of organisms, established a uniform system (binomial nomenclature); presented hierarchical classification (taxonomy)
Augustin Sagaret (1763-1851): crossed plants of a particular trait, usually got that same trait (appearance)
300s BC: Hippocrates-heredity material, throughout body
200s BC: Aristotle- material gained from semen (purified form of blood which mixed w/ the mother's menstrual blood)
800s CE: Al-Jahiz-inheritance of acquired characteristics, environmental factors influence organisms to develop new characteristics to ensure survival, thus transforming into new species."
1700s: increased taxonomy & diversity of plant/animal species, new ideas about heredity
1800s: crossing certain parent plants, particular characteristic, usually led to the appearance of the characteristic in the offspring
1859: Charles Darwin-The Origin of Species, evolution by natural selection; needed genetic inheritance
1866: Gregor Mendel-Experiments in Plant Hybridization, basic theory of genetics
1871: Friedrich Miescher- isolates “nucleic acid” whilst trying to wash the puss off dirty bandages at a local hospital
1879: Walther Flemming- discovers chromosomes using aniline dyesHistory of Genetics Before Mendel
Major Discoveries Circa WWI
1900: August Weismann-proposed inheritance takes place through germ cells
1902: Theodor Boveri (sea urchins) and Walter Sutton (grasshoppers) hereditary material is carried in chromosomes: firstly, all the chromosomes had to be present for proper embryonic development to take place; chromosomes occur in matched pairs of maternal and paternal chromosomes which separate during meiosis
1902: Archibald Garrod-recessive inheritance in humans
1910: Thomas Hunt Morgan- chromosome theory of heredity using the fruit fly; genes are linked in a series on chromosomes, responsible for hereditary traits
1919: Phoebus Levene-identified units of DNA which he calls "nucleotides". (base, a pentose sugar, & a phosphate group); hypothesis DNA structure: chains short & bases repeated
1928: Frederick Griffith- discovers harmless strain of bacteria could be dangerous after being exposed to heat; some kind of substance ("transforming principle") from the heat-killed strain was taken up & incorporated in the harmless strain, making them virulent
1937: William Astbury-X-ray diffraction patterns revealing DNA has a regular structure
Major Discoveries Circa WWI
ZymotechnologyStudy of fermentation (breakdown of
carbohydrates) Initially focused on beer…WWI, focused on
industrial problems◦ Due to industrial support of war -> massive production
Later called, biotechnology (1919)- “convert raw materials into a useful product”◦ Possible solutions for food and resource shortages
http://www.lifesciencesfoundation.org/events-item-111.html http://www.spartacus.schoolnet.co.uk/FWWinventors.htm
Major Discoveries Circa WWI
Eugenics: Refer to the “science of heredity”Eugenic groups appeared after WWI due to fear of
immigration (foreigners)◦ Race Betterment Foundation◦ American Eugenic Society (1923)
Promoted fine breedingDiscouraged maintaining people w/ undesirable traits
with others ◦ Banned reproducing (if allowed)
Attained some goals- Immigration Act (1924) passed by Congress, limited immigration through quotas, signed by President Coolidge
Behaviorism (1913) & Thomas Hunt Morgan’s genetic work helped reduced focus on eugenics◦ WWII-German actions on Jew completely disbanded the
movement
Major Discoveries Circa WWI
Rise in industrialism & mass production◦ Warfare technology
Wireless telegraphy, radio, telephone (often broken); used runners, mirrors, flashing lights, dogs, aircraft , microphones
Naval Warfare◦ Germany & Britain
Britain built HMS Dreadnaught, revolutionized ship building◦ Submarine: caused the US to enter the war (Germany attacked 1917)
Armaments, Supplies◦ Hand grenades & explosives: trench warfare◦ Barbed Wire: invented in 1874 to control cattle, was used to fence
trenches, troops would get tangled which permitted machine gun usage ◦ Machine guns (replaced Gatling guns), allowed quick, rapid shooting l
flame throwers (used by Germany)◦ Airplanes: invented 11 yrs prior to the war; two alliances would deny the
other air advantage – coined Flying Circus Red Baron: Manfred von Richthofen: pilot, shot down 80 planes Germany: Zeppelins (bombing raids) Observation Balloons: crew of 2, observed trenches
◦ Tanks: Allies (1915-16, 1917-used), not as decisive, helped win the Allied summer offensive of 1918
◦ Poison gas: used by Germany to stop “stalemate of trench warfare,” effects were fatal, wasn’t as utilized after 1916
◦ Railroads aided in the transport of artillery & troops
Vocabulary
Cell: structural, functional, and biological unit of all organisms
Organisms: all living thingsUnicellular: has one cellCytology: study of cellsOrganelles: small structure inside a cellProkaryotic Cells: simplest type of cell,
unicellular, most have a cell wall, asexual (reproduce through binary fission)
Eukaryotic Cells: complex type of cell, more organelles than prokaryotes, most are multicellular, undergo a process called differentiation
Important Figures
Democritus (460 BC)• All things are composed of “minute, invisible particles of
pure matter”
Hans & Zacharias Jansen (1590)• Created the early version of the compound microscope
Robert Hooke (1665)• Described the composition of cork through a compound
microscope: “tiny, hollow, room-like structures,” called them cells (were in actuality cell walls)
Anton van Leeuwenhoek (1670)• Improved lenses (allowed magnification), observed blood, rain,
teeth scraping, called some cells “animalcules” (bacteria)
Matthias Schleiden (1838)• Observed plant parts, discovered they were made of cells
Theodor Schwann (1839)• Observed animal parts, made of cells
Rudolph Virchow (1855)• All living cells come from other living cells
CELL T
HEO
RY
Important Figures
Caspar Wolff (1759)• All organs in animal embryos are made of “globules”
Felice Fontana (1781)• Described nucleolus, found in eel’s skin’s slime
Jean Baptiste de Lamarck (1809)• Declared that cellular tissue is the “general matrix of all organization”
Henri Dutrochet (1824)• All organic tissue is globular cells
Pierre Turpin (1826)• Observations on cell division
Franz Meyen (1830)• Cells form independent whole, which then builds itself up
Robert Brown (1831)• Discoveries of occurrence of nuclei
Hugo von Mohl (1839)• Described mitosis in plants
Anton Schneider (1873)• Observations of chromosomes during cell division
Gregor Mendel• Plant hybrids, genetics
Cell Theory
Discoveries of Hooke, Schleiden, and Virchow helped the formation of the theory
Improvement in microscopy permitted these discoveries
Consists of three parts1. Anything living is made up of cells2. Chemical reactions inside an organism occur in cells3. All cells come from preexisting cells
http://youtu.be/4OpBylwH9DUhttp://youtu.be/h85_U9OJFQ0
Modern Cell Theory
1. All known living things are made up of cells.2. The cell is structural & functional unit of all
living things.3. All cells come from pre-existing cells by
division. (Spontaneous Generation does not occur)
4. Cells contains hereditary information which is passed from cell to cell during cell division.
5. All cells are basically the same in chemical composition.
6. All energy flow (metabolism & biochemistry) of life occurs within cells.
Cell Evolution: Cell Wall
Diversity in molecular compositions Secondary cells walls, reinforced with lignin-provides
durability Some have pollen tubes that enable their tip growth Lupin seed cell walls are thicker due to galactan, a
storage polysaccharide Dependent on developmental stage, cell type, and
season. Plants & algae: phylogenetic history, endosymbiotic
events; “organisms that have the shared features of photosynthesis and possession of a cell wall do not form a monophyletic group”◦ Phylogenetic: study of evolutionary development of
organism, higher taxonomic groups Taxonomy: Classification of organisms based on shared feature
◦ Monophyletic: Descended from a single taxon
Cell Evolution: Endosymbiotic Theory
Endosymbiotic Theory: accepted assumption explaining how eukaryotes evolved from prokaryotes
Introduced by Lynn Margulis in the late 1960sStated that the main organelles of eukaryotes were
initially prokaryotes ◦ Endosymbiosis: organism lives inside another, mutually
beneficialOrganelles proposed to have been their own cell
include the mitochondria and chloroplast◦ Both organelles have their own DNA & ribosomes that do
“not match” the rest of the cell◦ Because of this, they can survive & reproduce
independently◦ Chloroplast DNA is alike to cyanobacteria ◦ Mitochondria DNA is alike to typhus bacteria
Cell Structures in Prokaryotes
Prokaryote: single celled organism w/ no nucleus, lack internal membranes◦ Plasma Membrane: around cytoplasm, regulates flow of substances in & out
of cell◦ Cytoplasm: Gel-like substance that is made of mostly water & enzymes,
salts, cell components, & organic molecules◦ Nucleoid Region: area of cytoplasm that contains the single bacterial DNA
molecule◦ Ribosomes: responsible for protein production◦ Plasmids: Gene carrying, circular DNA structures (not involved in
reproduction)◦ Cell Wall: outer covering, protects, & gives cells their shape◦ Suface Appendages:◦ Pili: hair-like structures that attach to other bacterial cells
Fimbriae: shorter pili, help bacteria attach to surface◦ Flagella: long, whip-like protrusion that aids in cellular locomotion
Cellular Locomotion: http://www.youtube.com/watch?v=Jt1oMaxrp3U◦ Capsule: outer covering protecting the cells when it is swallowed by other
organisms, retains moisture, and helps cell hold on to surfaces & nutrients ◦ http://www.vetmed.vt.edu/education/curriculum/vm8054/Labs/Lab3/Lab3.htm
Cell Structures in Eukaryotes
Plasma Membrane: thin, semi-permeable membrane that surrounds cytoplasm of a cell, enclosing its contents◦ http://www.youtube.com/watch?feature=player_embedded&v=Mv247P8ufCA
Cytoplasm: gel-like substance within the cell containing water, enzymes, salts, organelles
Cell Wall: outer covering of the cell that protects the plant cell and gives it shape Nucleus: membrane bound structure that contains the cell’s hereditary
information◦ Nucleolus: structure w/in the nucleus, helps in synthesis of ribosomes, RNA◦ Nucleopore: tiny hole within nuclear membrane that allows nucleic acids and protein to
move into & out of the nucleus Extracellular Matrix: support, adhesion, movement, and cell regulation Chromatin: chromosomes DNA and protein Nuclear Envelope: ER, golgi apparaturs, vacuoles, plasma membrane Ribosome: consist of RNA & protein, responsible for protein assembly Rough Endoplasmic Reticulum: synthesis & packing of proteins Smooth Endoplasmic Reticulum: storage of steroids and ions Golgi Apparatus: responsible for manufacturing, storing, & shipping certain
cellular products Lysosomes: sacs of hydrolytic enzymes that digest cellular macromolecules such
as nucleic acids Vesicles: small, contains proteins, enclosed by phospholipids layers Centrioles: organize the assembly of microtubules during cell division
Cell Structures in Eukaryotes
Mitochondria: power producers and the sites of cellular respiration Microtubules: hollow rods that function to help support & shape cells Chloroplasts: sites of photosynthesis in a plant cell, contain chlorophyll
(green pigment that absorbs energy from the sunlight) Central Vacuoles: structure in a plant cell that provides support and
participates in a variety of cellular functions including storage, detoxification, protection, and growth
Peroxisomes: tiny structures bound by a single membrane that contain oxidative enzymes that produce hydrogen peroxide as a byproduct, help in photorespiration
Centrosomes: contains microtubules, as centrioles, regulator of “cell-cycle”
Cilia & Flagella: protrusions that aid in cellular locomotion Cytoskeletal Elements: network of fibers in the cytoplasm that helps the
cell maintain its shape◦ Microtubules: hollow rods, help support and shape cell, “routes” along which organelles
can move, responsible for chromosome movement in cell division, movement of organelles◦ Microfilaments/Actin Filaments: solid rods, help in muscle contraction, cell division,
maintenance of cell shape◦ Intermediate Filaments: provide support for microfilaments and microtubules by holding
them in position, anchor nucleus, forms nuclear lamina Endomembrane System: contains different membranes in the cytoplasm,
divide the cell into organelles
Subcellular Organelles Involved in Cell Reproduction
Nucleus: control center & location for genetic information replication (contains DNA), DNA binds to proteins (histones) & form nucleosomes; RNA is obtained from DNA & interpreted
Centrosomes: microtubules are produced, contains centrioles; cell division-centrosome divides & centrioles replicate resulting in 2 centrosomes w/ centrioles, they move to opposite side of nucleus where microtubules become a spindle ◦ Spindle: separates replicated chromosomes into the
daughter cells Microtubules: form spindle fibers, manipulate &
separate chromosomes during mitosis Cell Membrane: closes and splits the cell into two
daughter cells (telophase during mitosis) Cell Wall: splits in half when the daughter cells divide