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8/3/2019 Biology 2nd Quarter (Ppt Notes + Other Notes)
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Amica !
Biology 2nd
Quarter
I. Origin of LifeA. Formation of the Universe
Big Bang Theory- massive blast allowed all the universe's known
matter and energyeven space and time
themselvesto spring from some ancient and
unknown type of energy
Biological Evolution- Populations of organisms change over the
course of many generations (genetic changes)
B. Formation of The Solar System Explosion of a Super Nova
- disturbed cloud of gas and dust- cloud grew hotter and denser in the center (hot
center, cool edges)
C. Formation of the EarthStage 1: Origin of Organic Molecules (Nucleotides and
amino acids were produced prior to the existence of
cells)
Alexander Oparin- One of the two scientists who independently
hypothesized the abiotic formation of organic
compounds
- Coacervates (stable, mostly hydrophobic)** Microspheres cool water + organic compounds
JBS Haldane- One of the two scientists who independently
hypothesized the abiotic formation of organic
compounds
Prebiotic Soup // Primordial Soup- Abiotic synthesis of small organic molecules
amino acids and nucleotides
- Slow accumulations of molecules in earlyoceans over a long period of time
- Key event that preceded the origin of life Reducing Atmosphere Hypothesis
- Primitive earth was rich in H20, H2, CH4, NH3;no oxygen
- Later concluded that atmosphere was notreducing but was a neutral environment mostly
of CO2, CO, N2, H20 (UV destroys CH4 & NH3)
Extraterrestrial Hypothesis- Sufficient organic carbon would have been
present in the asteroids and comets
Why Spontaneous Generation cannot happen today:1. because atmosphere is oxygen rich2. oxidizing atmosphere today not conducive3. o2 attacks chemical bonds extracting electrons4. less UV radiation that helps in forming organic
molecules
Spontaneous Generationa. Francesco Redi- Flies produce maggots- Conclusion: maggots form only when fibers
come in contact with the meat
b. John Needham- Spontaneous generation could occur under the
right conditions
- Sealed and heated bottle of gravyc. Lazaro Spallanzani- Needham had not heated his samples enough- Microorganisms in the concealed jar were off
springs of microorganisms that had entered the
jar through the air
d. Louis Pasteur- S shaped flask- All living things come from other living things
Harold Urey- One of two scientists who tested the Oparin-
Haldane Hypothesis
- Teacher Stanley Miller
- One of two scientists who tested the Oparin-Haldane Hypothesis
- Student
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Rain or
waves
Dilutesolutions ofmonomers
LAVAProteinoids
andpolymers
water
Experiment:
Early atmosphere - H2O, H2, CH4, NH3, CO, CO2,N2, water vapour
The experiment had produced - 20 Amino acidsfound in organisms, sugars, lipids, purines,
pyrimidines, even ATP
** Lab simulations of the early earth conditions produced
organic polymers
** Natural process in organisms: Enzymes catalyze reactions
Sydney Fox- Protenoids: polypeptides from abiotic means
Stage 2: Organic polymers from surface of clay (nucleotides
and amino acids polymerized)
J. Bernal- Prebiotic synthesis of polymers took place on
clay
A. G. Cains-Smith- clays might have been the first templates for
self-replicating systems
- Pyrite: Charged surfaceStage 3: Cell-like structures when polymers were enclosed by
a boundary (polymers in membranes)
Protobionts- Aggregates of abiotically produced molecules
that cant reproduce precisely
- First non-living structures that evolved intoliving cells
- Boundary separated it from the externalenvironment
- Polymers contained information- Polymers had enzymatic functions- Capable of self replication but not precisely
Coacervates (Oparin)- Droplets that form spontaneously from
association of charged polymers (cluster)
Liposomes- Vesicles surrounded by a lipid bilayer
Microspheres- Small water filled vesicles surrounded by a
macromolecular boundary
Stage 4: Cellular Properties via Chemical Solution; RNA World
RNA- first genetic material- short polymers of ribonucleotides have been
produced abiotically in the laboratory
- revolution thinking about the evolution of lifewhen they discovered that RNA molecules are
important catalysts in modern cells
- ribosomes use rna catalyts: rRNA (ribosomal),tRNA(transcription) and mRNA(messenger)
- capable of self replication RNA World
- When both information needed for life andenzymatic activity for living cells were
contained only in the RNA molecules
DNA- Stores information for the amino acid sequence
of proteins
Central Dogma- DNA, RNA and Protein- DNA RNA (transcription)- RNA DNA (reverse transcription retro
viruses)
- RNA Proteins (translation) 5 Descriptions of FIRST LIFE
1. Unicellular2. Asexually reproducing3. Aquatic environment4. RNA containing5. Heterotrophic
II. Cell: Organic Unit of Life Cell
- basic unit of structure and function- Can be:o Unicellularo Multicellular - Bodies are cooperative of
specialized cells; Cannot survive for long on
their own
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How do we study cells?- Telescope // Microscope- Anton von Leeuwenhoek: first to explore
things: microscopic view
ESSENTIAL SCIENTISTS
a. Robert Hooke- Cells composed of thousands of chambers
b. Robert Bown- Nucleus: Dark structure
c. Matthias Schleiden- all plants are made up of cells
d. Theodor Schwann- all animals are made up of cells
e. Rudolf Virchow- Cells arise from the division of pre-existing cells
CELL THEORY most fundamental discovery: nature of living things forms basic framework formulated by Schwann, Schleiden and Virchow
States that:
all living things are composed of cells cells are the basic unit of structure and function all cells come from pre-existing cells
PROKARYOTIC VS EUKARYOTIC
ORGANELLES
Nucleus- contains most of the genes*Nuclear envelope
> Encloses nucleus
> Double membrane (lipid bilayer with proteins)
Nuclear lamina - netlike array of proteinfilaments maintains the shape of the nucleus
Nucleolus - Site: components of ribosomes aresynthesized and assembled; Components pass
through the nuclear pore to the cytoplasm;
Appears as a mass of densely stained granules
and fibers adjusting part of chromatin
Ribosomes- Protein factory- cells with active protein synthesis- prominent nucleoli- Free ribosomes: cytosol- Bound ribosomes: for inclusion, transport,
packaging
ENDOMEMBRANE SYSTEM
Membranes that are related either: direct physicalcontinuity or transfer of membrane segments
Includes: VAly PLAne GOerNuclear Envelope, ER, Golgi Apparatus, Lysosomes,
Vacuoles, Plasma Membrane
Endoplasmic Reticulum- more than half the total membrane of cells- reticulum Greek word for networka. Smooth ER
o Smooth walls of the sacs are not studdedwith ribosomes
o Functions: SYLIP me car DE DRUPSynthesis of lipids
Metabolism of carbohydrates
Detoxification of drugs and poison
b. Rough ERo studded with ribosomeso Functions:
synthesis of secretory protein
membrane production
synthesis of proteins
Golgi Apparatus- Center of: MWSS
Manufacturing Warehousing Sorting Shipping
- Products from the ER are: SMS Modified Stored Sent to other destinations
Vacuoles- membrane bound sacs in a cell- Repository of inorganic ions- Storage of pigments- Helps to protect against predators- food vacuole- formed by phagocytosis- Contractile vacuole
Pumps out water out- Central Vacuole- filled with liquid
PROKARYOTIC
Pro- before Karyon- kernel no nucleus DNA: concentrated in
a NUCLEOID
With cytoplasm w/ Plasma Membrane
EUKARYOTIC
Eu- true Karyon- kernel Has NUCLEUS With cytoplasm
Cytosol w/ Plasma Membrane
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Tonoplast organic compounds (proteins in seed) Disposal sites for metabolic products
Lysosomes- membrane bounded sacs of hydrolytic enzymes- digestion of macromolecules-
works best in acidic medium ~pH 5- maintains internal pH- excessive leak of a large number- leads to auto digestion
Plasma Membrane- Controls traffic into and out of the cell- Selective permeable- Membrane structure: Charles Overton - it is made of lipids- RBC- composed of lipids and proteins- made up of phospholipids- Amphiphatic Irvin Langmuir - Artificial membranes;
Phospholipids in benzene* + water
Gunter and F. Grendel - phospholipid bilayer;Suggests: stable boundary between two
aqueous compartments; Measured lipid
content in RBC
S.J. Singer and G. Nicolson Fluid MosaicModel: mosaic of protein molecules in a fluid
bilayer of phospholipids
OTHER MEMBRANE ORGANELLES
not part of Endo-Membrane System membranes not made by ER
Free ribosomes and Ribomes of Mitochondriaand Cytoplasm
contain small amounts of DNA semi- autonomous Mitochondria
- power house of the cell- site of cellular respiration
Catabolic process that generates ATP- number related to cells metabolic activity- enclosed by two membranes
Outer- smooth Inner- convoluted with infoldings (cristae)
Chloroplast- found in plants and eukaryotic algae- site of photosynthesis- Solar energy chemical energy- member of plastids- Amyloplasts- colorless, stores starch
- Chromoplast- stores pigments- contains another membranous system THYLAKOIDS- flattened sacs- forms GRANA- bathed with stroma
Peroxisomes- specialized metabolic compartment bounded
by a single membrane
- sontains enzymes that produces* H2O2 as a byproduct
- Function:Use O2 to break Fatty acids
Detoxify alcohol
Transferring H2 from the poisons to oxygen
Cytoskeleton- Organization of structures and its activities- Mechanical support- Maintains shape
Important to animal cells- Anchorage for organelles- cell motility3 MAIN TYPES of FIBERS Microtubules - Straight hollow rods; Made from
Tubulin; Shape and support; Tracks for
organelles equipped with motor proteins;
Involved in cell division
Cilia and Flagella - Core of microtubulessheathed in an extension of the Plasma Mem.
Microfilaments - Solid rods; bear tension Cell Wall
- Plant cells only- Protection- Maintains shape- Prevents excessive uptake of water- Made up of cellulose
Extracellular Matrix- Support; Adhesion; Movement; Regulation- Components: Collagen: forms strong fibers outside the cell;
Protein rich in carbohydrates
Fibronectin: attached to the ECM; Bind toreceptor proteins INTEGRIN*
- Regulate cell behavior- Influence activity of genes
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III. Terms in Microscopy Magnification
- how much larger the object appears comparedto pts real size
Resolving power- Measure of the clarity of the image-
Minimum distance two points can be separatedand still be distinguished as 2 separate points
Resolution- Limited by the wavelength of light used to
illuminate the specimen
TYPES OF MICROSCOPES
a. Light Microscopes- visible light is passed through the specimen- lenses: refract light (image is magnified)- can magnify effectively to about 1000x the size
of actual specimen
b. Electron Microscope- focuses beam of electrons- uses shorter wavelengths- Resolution power: inversely proportional to the
wavelength of radiation
Transmission Electron Microscopeo aims an electron beam through a thin
specimen
o Uses electromagnetso image is focused on a screen or on
photographic film
o heavy metals for staining Scanning Electron Microscope- detailed study of the surface of specimen- electron beam scans the surface- coated with thin film of gold- electron beam excites the electron on the
samples surface
IV. DiseaseDisease
-
any change (other than an injury) that interferes withthe normal body function
- impair normal tissue functionInfectious Disease
- caused by infectious agents- acquired: contact w someone carrying disease;
contaminated objects, food, air
- Spread:olio virus contaious not virulent bolahemorrhaic fever virulent not contaious
D: results from the invasion and growth of a pathogen; tissue
function is impaired
I: results when a pathogen invades and begins growing within a
host; bodily function: normal
Can be:
a. Genetic (Cystic fibrosis, Hemophilia)b. Aging (Atherocslerosis, osteoporosis)c. Infectious (German measles, Chicken pox, Malaria)
Pathogens
- microorganisms that are capable of causing disease- infectious agent that causes disease in virtually any
susceptible host
Opportunistic Pathogens
- potentially infectious agents- Found on
elderly immuno suppressed cancer patients immuno- compromised people who have AIDS or are HIV-positive (immuno-
compromised
Types:
a. Viral Infections (colds, influenza, measles, chickenpox, West Nile virus, hepatitis, AIDS)
b. Bacterial infection (pneumonia, strep throat, boils,acne, streptococcal infection, bubonic plague, and
anthrax)
c. Protozoan infections (Malaria, amoebiasis andDiarrhea)
d. Fungal infections (yeast infections, ringworm andathlete's foot)
e. Helminthes Infection - simple, invertebrate animals,some of which are infectious parasites
(Schistosomiasis Liver fluke disease)
How they harm the host...
1. enter the host body2. adhere to specific host cells (invade and colonize)3. multiply between host cells or within body fluids
(cause tissue damage)
4. production of toxins or destructive enzymesGerm Theory
- states that microorganisms can cause diseases- infectious disease is caused by an infectious agent- Loius Pasteur, Robert Koch
Robert Koch
- use of agar as solid medium.- invented nutrient broth and nutrient agar
Kochs ostulates
1. The pathogen should always be found in the body ofa sick organism
2. Pathogen should be grown and isolated in the lab inpure culture
3. When placed in a new host, pathogen should causethe same disease
4. Injected pathogen should be re-isolated
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Vectors animals who carry the disease
Modes of Infection:
a. Direct contact with reservoirb. Indirect contact - when a pathogen can withstand the
environment outside its host for a long period of time
before infecting another individual
c. ir - borne droplet infection colds, flu, sinusinfections, German measles
d. Vectors - carry disease throuh other animals einsect bites typhus, rabies, H- fever, malaria, dengue
Defense:
Structural Defense- Skin, mucous membranes- perspiration salts and fatty acids- tears (contain lysozyme which can break down
bacterial cell all
- acid secretion in stomach l Cellular
-
Phagocytosis (leucocytes in WBC)
Antibiotics- Interfere with the cellular process of microorganisms
Specific mechanisms of host resistance
- white blood cells called lymphocytes:- -cells produced from lymphocytes that matured in
the thymus land
- B-cells (produced from lymphocytes that matured inthe bone marrow)
V. VirusesVirus
- infectious agent (parasites of animals, plants andsome bacteria)
- parasitic non-cellular particle- Consists of: nucleic acid core -protein coat- metabolism and reproduction: needs living cell / host
Reproduction1. initiates the synthesis of viral proteins2. undergoes replication3. new viruses are released
VIRUS VS. FREE LIVING CELLVIRUS
Acellular can not live independently Either DNA or RNA
FREE LIVING CELL
can grow, reproduce, regulate gene expression can evolve independently
Tobacco Mosaic Virus- bleached spots that form a pattern that farmers
called a mosaic
- leaves turn yellow, wither and fall off, killing the plant Dimitri Iwanowski
- juice taken from diseased plants-
placed extract on the leaves of healthy plants- healthy plants became infected
Martinus Beijerinck- named the disease causin particle virus Latin for
poison
Wendell Stanley- chemically isolates and identifies the disease causing
particle as the Tobacco Mosaic Virus (TMV)
- through electron microscopyBASIC STRUCTURE
CLASSIFICATION OF VIRUSES
a. Genetic Material DNA or RNA (never both)b. Shapec. Sized. Presence of Envelope - enveloped viruses enclosed by a
membrane (portion of host cell or nuclear membrane)
e. Specificityf. Disease Type Prions
- Infectious proteins- Scrapie in sheep- Creutzfeldt Jacob Disease- humans
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Viroids- Naked circular molecules of RNA that infect plants- Disrupts plants metabolism
LIFE CYCLE
1. Infection - chance of contact2. Growth - DNA of the virus
RNA polymerase viral mRNAwrecking crew
3. Replication - 25min (in E. coli Lysogenic cycle temperate/ avirulent phage
IMPORTANCE OF VIRUS
Pathogenic- Defense vs. viral infection- Discovery of vaccines
ORIGIN OF VIRUSES
Pieces of cellular DNA became a part of an infectiousparticle
Not likely to have been the 1st living things on earth Evolved from the genetic material of living cells