Transcript Cellular Reproduction

Cellular Reproduction
A Brief History of Genetics Before Mendel
Major Discoveries Circa World War I
History of Discovery of Cells
Evolution and Diversity of Cells
Architecture of Cells
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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
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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”
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History of Genetics Before Mendel
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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
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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)
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History of Genetics Before Mendel
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 dyes
History of Genetics Before Mendel
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
Zymotechnology
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Study of fermentation (breakdown of
carbohydrates)
Initially focused on beer…WWI, focused on
industrial problems
◦ Due to industrial support of war -> massive production
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Later called, biotechnology (1919)- “convert raw
materials into a useful product”
◦ Possible solutions for food and resource shortages
 http://www.lifesciencesfoundation.org/events-item111.html
 http://www.spartacus.schoolnet.co.uk/FWWinventors.htm
Major Discoveries Circa WWI
Eugenics:
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Refer to the “science of heredity”
Eugenic groups appeared after WWI due to fear
of immigration (foreigners)
◦ Race Betterment Foundation
◦ American Eugenic Society (1923)
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Promoted fine breeding
Discouraged maintaining people w/ undesirable
traits with others
◦ Banned reproducing (if allowed)
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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
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Rise in industrialism & mass production
◦ Warfare technology
Wireless telegraphy, radio, telephone (often broken); used
runners, mirrors, flashing lights, dogs, aircraft , microphones
 Naval Warfare
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◦ Germany & Britain
 Britain built HMS Dreadnaught, revolutionized ship building
◦ Submarine: caused the US to enter the war (Germany attacked 1917)
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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
Major Discoveries Circa WWI
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Cell: structural, functional, and biological unit of
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Organisms: all living things
Unicellular: has one cell
Cytology: study of cells
Organelles: small structure inside a cell
Prokaryotic Cells: simplest type of cell,
all organisms
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
Vocabulary
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
•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
Important Figures
CELL THEORY
Robert Hooke (1665)
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
Gregor Mendel
•Plant hybrids, genetics
Anton Schneider (1873)
•Observations of chromosomes during cell division
Important Figures
Discoveries of Hooke, Schleiden, and
Virchow helped the formation of the theory
 Improvement in microscopy permitted
these discoveries
 Consists of three parts
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1. Anything living is made up of cells
2. Chemical reactions inside an organism occur in cells
3. All cells come from preexisting cells
http://youtu.be/4OpBylwH9DU
 http://youtu.be/h85_U9OJFQ0
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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.
Modern Cell Theory
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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: Cell Wall
Endosymbiotic Theory: accepted assumption
explaining how eukaryotes evolved from
prokaryotes
 Introduced by Lynn Margulis in the late 1960s
 Stated that the main organelles of eukaryotes
were initially prokaryotes
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◦ Endosymbiosis: organism lives inside another, mutually
beneficial
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Organelles 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 Evolution: Endosymbiotic Theory
Prokaryotes
Eukaryotes
Animal
Plant
Bacteria
Prokaryotes vs. Eukaryotes
Prokaryotes vs. Eukaryotes
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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 Prokaryotes
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Plasma Membrane: thin, semi-permeable membrane that surrounds
cytoplasm of a cell, enclosing its contents
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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
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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
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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 “cellcycle”
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
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Endomembrane System: contains different membranes in
the cytoplasm, divide the cell into organelles
Cell Structures in Eukaryotes
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
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◦ 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
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Subcellular Organelles Involved in Cell Reproduction