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8/3/2019 Biology 2nd Quarter (Ppt Notes)
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Amica !
Rain orwaves
Dilute
solutions of monomers
LAVAProteinoids
andpolymers
water
Biology 2nd
Quarter
I. Origin of Life
A. Formation of the Universe
Big Bang Theory
- massive blast allowed all the universe's known
matter and energy—even space and time
themselves—to spring from some ancient and
unknown type of energy
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 Earth
Alexander Oparin
- One of the two scientists who independently
hypothesized the abiotic formation of organic
compounds
JBS Haldane
- One of the two scientists who independently
hypothesized the abiotic formation of organic
compounds
Prebiotic Soup
- Abiotic synthesis of small organic molecules
amino acids and nucleotides
Why Spontaneous Generation cannot happen today:
1. because atmosphere is oxygen rich2. oxidizing atmosphere today not conducive
3. o2 attacks chemical bonds extracting electrons
4. less UV radiation that helps in forming organic
molecules
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
Experiment:
Early atmosphere - H2O, H2, CH4, NH3, CO, CO2,
N2, water vapour
The experiment had produced - 20 Amino acids
found 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
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 surface
Protobionts- Aggregates of abiotically produced molecules
that can’t reproduce precisely
RNA
- first genetic material
- short polymers of ribonucleotides have been
produced abiotically in the laboratory
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- revolution thinking about the evolution of life
when they discovered that RNA molecules are
important catalysts in modern cells
- ribosomes use rna catalyts: rRNA, tRNA and
mRNA
- capable of self replication
5 Descriptions of FIRST LIFE1. Unicellular
2. Asexually reproducing
3. Aquatic environment
4. RNA containing
5. Heterotrophic
II. Cell: Organic Unit of Life
Cell
- basic unit of structure and function
- Can be:
o Unicellular
o Multicellular - Bodies are cooperative of
specialized cells; Cannot survive for long on
their own
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 protein
filaments maintains the shape of the nucleus
Nucleolus - Site: components of ribosomes are
synthesized 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 physical
continuity or transfer of membrane segments
Includes: VAly PLAne GOer
Nuclear Envelope, ER, Golgi Apparatus, Lysosomes,
Vacuoles, Plasma Membrane
Endoplasmic Reticulum
- more than half the total membrane of cells
- reticulum Greek word for network
a. Smooth ER
o Smooth walls of the sacs are not studded
with ribosomes
o Functions: SYLIP me car DE DRUP
Synthesis of lipids
Metabolism of carbohydrates
Detoxification of drugs and poison
b. Rough ER
o studded with ribosomes
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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o 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
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 Mosaic
Model: 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 Mitochondria
and 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 cell’s 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 by
product
- 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 motility
3 MAIN TYPES of FIBERS
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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 microtubules
sheathed 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 to
receptor proteins – INTEGRIN*
- Regulate cell behavior
- Influence activity of genes
III. Terms in Microscopy
Magnification
- how much larger the object appears compared
to pts real size
Resolving power
- Measure of the clarity of the image
- Minimum distance two points can be separated
and 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 Microscope
o aims an electron beam through a thin
specimen
o Uses electromagnets
o 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
sample’s surface
IV. Disease
Disease
- any change (other than an injury) that interferes with
the normal body function
- impair normal tissue function
Infectious Disease- caused by infectious agents
- acquired: contact w someone carrying disease;
contaminated objects, food, air
- Spread: olio virus contaious not virulent bola
hemorrhaic 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, chicken
pox, West Nile virus, hepatitis, AIDS)
b. Bacterial infection (pneumonia, strep throat, boils,
acne, streptococcal infection, bubonic plague, and
anthrax)
c. Protozoan infections (Malaria, amoebiasis and
Diarrhea)
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d. Fungal infections (yeast infections, ringworm and
athlete'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 body
2. 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 enzymes
Germ Theory
- states that microorganisms can cause diseases
- infectious disease is caused by an infectious agent
Robert Koch
- use of agar as solid medium.
- invented nutrient broth and nutrient agar
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,
sinus infections, German measles
d. ectors - carry disease throuh other
animals e insect bites typhus, rabies, H-
fever, malaria, dengue
Defense:
Structural Defense
- Skin, mucous membranes
-
perspiration salts and fatty acids- tears contain lysoyme hich can brea don
bacterial cell all
- acid secretion in stomach l
Cellular
- Phagocytosis (leucocytes in WBC)
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 in
the bone marrow)
V. Viruses
Virus
- infectious agent (parasites of animals, plants and
some bacteria)
- parasitic non-cellular particle
- Consists of: nucleic acid core -protein coat
- metabolism and reproduction: needs living cell / host
Reproduction
1. initiates the synthesis of viral proteins
2. undergoes replication
3. new viruses are released
VIRUS VS. FREE LIVING CELL
VIRUS
• 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 microscopy
BASIC STRUCTURE
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CLASSIFICATION OF VIRUSES
a. Genetic Material – DNA or RNA (never both)
b. Shape
c. Size
d. Presence of Envelope - enveloped viruses enclosed by a
membrane (portion of host cell or nuclear membrane)
e. Specificity
f. Disease Type
Prions
- Infectious proteins
- Scrapie in sheep
- Creutzfeldt Jacob Disease- humans
Viroids
- Naked circular molecules of RNA that infect plants
- Disrupts plants metabolism
LIFE CYCLE
1. Infection - chance of contact
2. Growth - DNA of the virusRNA 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 infectious
particle
• Not likely to have been the 1st
living things on earth
• Evolved from the genetic material of living cells
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