2. CELL THEORY
• It summarizes the basic concept of life.
• It states:
1. All living things are made up of cells.
2. Cell is the fundamental unit that can function by itself.
3. Cells come from preexisting cells.
• Cell theory is described because of the curiosity of scientist inside and
around them.
• Next slide shows the timeline of the discovery of cell.
3. 1665
Robert Hooke, England
Cork-rows of empty
compartments resembling a
honeycomb-cells.
Anton Van Leeuwenhoek,
Netherlands
“animalcules” in water
1809
Jean Baptiste Pierre Antoinne de
Monet, France
Cells are filled with fluids
1831
Robert Brown, England
Cell nucleus
Rudolf Virchow
Cell divide to form new cells
1835
Dujardin of France
Sarcode (substance inside the
cell)
1839
Johannes Purkinje,
Czechoslovakia
Discovered “protoplasm”
1924
Dutrochet
The cell is the fundamental part
of living organism.
Matthias Schleiden and
Theodore Schwann
Cells perform fundamental
function in a living organism.
Timeline of the Discovery of Cells
5. MICROORGANISM
• are very tiny organism which are unicellular (single cell) or multicellular (2 or more
cells). These include bacteria, fungi, and protists. Protists include algae, protozoans,
and yeasts.
• Microbiology – study that involves microorganisms. Where are organisms found?
What are their significance?
6. SIGNIFICANCE OF MICROORGANISMS
1. Decomposers – clean up waste products and remains of dead organisms by
decomposition.
2. Biotechnology – food and beverage preparations and genetic engineering.
3. Bioremediation – cleaning up oil spills, soil, and water pollutants. Microorganism are
called biofilters.
4. Pharmaceuticals – sources of antibiotics.
5. Microflora (gut flora) – break down undigested food and Vitamin K (probiotics – bacteria
that can be eaten)
6. Food industry – used in fermenting products, to manufacture cheese, pickles, chocolates,
bread, wine, and soy sauce.
7. Scientific research – used for research and good for transport for engineered genes into
the DNA
8. Nitrogen fixers – take part in the nitrogen cycle
9. Weather changes – airborne microbes are participants in changes weather as in
precipitation.
7. KINGDOM OF DIFFERENT
MICROORGANISMS
• Microorganisms caused many infectious disease.
- pathogenic bacteria (diarrhea, tuberculosis, anthrax)
- protozoa (malaria, and sleeping sickness)
- viruses (influenza, yellow fever, and AIDS)
• BUT virus is not considered as microorganisms, thus does not
belong the kingdoms.
8. 1. KINGDOM ARCHAEBACTERIA
(ANCIENT BACTERIA)
- thrive in extreme conditions. It three major known groups of
Archaebacteria:
a. Methanogens – anaerobic bacteria (live w/out oxygen that
produce methane.
b. Halophiles – live on very salty environment, saltier than
seawater.
c. Thermophiles - thrive on very hot environment (60-80o C)
9. 2. KINGDOM EUBACTERIA
- metabolism are more diverse than that of archaebacteria. Some
manufacture their own food and have cell walls made of
carbohydrate that enclose the cell membrane.
- Genus Anabacteria - blue-green bacteria that produce its own
food by photosynthesis.
- Another genera:
a. Salmonella – produce lethal toxins
b. Rhizobium – found in legumes
c. Streptomyces – important source of antibiotics.
10. 3. KINGDOM FUNGI
• are a kingdom of usually multicellular eukaryotic organisms that are
heterotrophs (cannot make their own food) and have important roles in
nutrient cycling in an ecosystem. Fungi reproduce both sexually and
asexually, and they also have symbiotic associations with plants
and bacteria.
• examples:
a. Saccharomyces cerevisiae or yeast
b. Agaricus bisporus or mushroom
c. Candida albicans - grows naturally inside the human body, but sometimes
it can grow excessively and cause a yeast infection.
11. 4. KINGDOM PROTISTA
• Unicellular organisms known to be the simplest eukaryotic
organisms. They produce sexual and asexual means. They
possess flagella, psuodoposia or cilia that can help them to
move. Protozoans, live by heterotrophic mode of nutrition or by
ingesting food.
• Examples:
• Amoeba
• Paramecium
• Algae
12. NINE MAJOR PHYLA OF PROTISTS
a. Phylum sarcomastigophora
b. Phylum sarcodina
c. Phylum labyrinthomorpha
d. Phylum ciliophora
e. Phylum apicomplexa
f. Phylum myxomycota
g. Phylum microspore
h. Phylum sporozoa
i. Phylym zoomastigina
14. VIRUS
• It is a Latin name for poison.
• They are submicroscopic, intracellular parasites consisting of either
RNA or DNA but never both. They have protective coat of protein
alone or in combination with lipid or carbohydrate componenets.
• It was known when Dmitry I. Ivanovitch discovered microscopic
particles later known as tobacco mosaic virus. In 1898, Dutch botanist
Martinus W. Beijerinck then applied the word virus to these infectious
particles. In 1935 American biochemist Wendell Meredith Stanly was
able to crystallize tobacco mosaic virus and found that it is only made
up of genetic material RNA and a protein covering.
15. PARTS OF VIRUS
1. Capsid – protein shell
2. Capsomeres – protein
subunits
Virion – term given to a complete
virus particle. They are obligate
intracellular parasites (cannot
reproduce and grow alone without a
host that will supply them with
active metabolizing cells to help
them grow and replicate).
16. GROUPS OF VIRUSES
1. Isometric – smallest virus;
the icosahedons (20 sided
polygon), belong to this
group measuring about 18-
20 nanometers.
17. 2. Rod-shaped or
elongated – the largest
virus belong to this group
measuring several microns
(10-6 METERS) in length, less
than 100 nanometers in
width.
18. 3. Tadpole-like (with head and tail) –
ranging about 60-300 nanometers in
diameter, the viruses in this group are
complez
19.
20. HOW DOES A VIRUS REPLICATE?
1. Virus attaches and enters a host cell.
2. Virus coat is removed by cellular enzymes, virus RNA or DNA is in contact with
ribosomes.
3. Virus directs synthesis of proteins specified by viral nucleic acid.
4. Nucleic acid replicates and protein units of viral coat synthesized two components
(viral nucleic acid and proteins) are assembled into new virus.
5. Virions are released destruction of infected cell, or bybudding through cell
membranes (does not kill the cell). Some infections are “silent” (viruses replicate
within in the cell causing no cell damage
