2. Which among the following groups of organisms are
not considered cells?
a.Bacteria
b.Fungi
c.Virus
d.Algae
3. Which among the following types of microscopes is
used together with computers to produce a three-
dimensional image and it is useful in the study of cell
physiology?
a.Phase-contrast microscope
b.Scanned-probe microscope
c.Fluorescent microscope
d.Confocal microscope
4. Which among the following parts of the microscope is
used to gather and focus light onto the specimen?
A.Coarse adjustment
B.Fine adjustment
C.Eye piece
D.Condenser
5. Who among the following scientists prove that
bacteria could cause a disease?
A. Louis Pasteur
B. Alexander Fleming
C. Edward Jenner
D. Robert Koch
6. PROKARYOTIC AND EUKARYOTIC CELLS
• Prokaryotes are organisms that do not posses
a true nucleus and membrane-bound
organelles (e.g., bacteria)
• Eukaryotic organisms are those that posses a
true nucleus and membrane-bound organelles.
They are usually multicellular organisms and
include plants, fungi, parasites, and algae.
7.
8. Prokaryotic Eukaryotic
Genetic material Not enclosed within a
membrane; not associated with
histones; usually circular
Enclosed within a membrane;
associated with histones; usually
linear
Size Smaller (1-2 micrometer by 1-4
micrometer or less)
Greater than 5 micrometer in
diameter
Cell type Mostly unicellular Mostly multicellular
Nucleus No true nucleus and nuclear
membrane; nucleoid
With true nucleus enclosed by
nuclear membrane
Cell wall Simple Complex
Cell division Budding or binary fission Mitosis
Sexual
reproduction
No meiosis; transfer of DNA only Meiosis
Cytoskeleton Absent Present
9. Prokaryotic Eukaryotic
Mesosome Function as mitochondria
and Golgi complex
Absent
Ribosomes 70S; located in cytoplasm 80S; located in membrane
such as ER
70S; found in organelles such
as mitochondria or
chloroplast
Membrane-bound organelles Absent Present
Extrachromosomal plasmid Present Absent
Duration of cell cycle Short (20-60mins) Long (12-24 hrs)
10. CHECKPOINT!
• What are histones?
• Is bacteria prokaryote or eukaryote?
• Give an example of membrane bound
organelles
13. VIRUSES
• Acellular organisms
• Their outer surface is called CAPSID
• Possess only a single nucleic acid, either DNA or RNA,
but never both
• Lack the necessary cellular parts that can allow them to
replicate independent of the host cell
• They also lack the genes and enzymes that are necessary
for energy production
• Obligate intracellular parasites
14. VIRUSES ARE CLASSIFIED BASED ON THE FF:
• Type of nucleic acid they posses
• Shape of the capsid (icosahedral, helical, polyhedral, or
complex)
• Number of capsomeres
• Size of the capsid
• Presence or absence of envelope
• Type of host they infect (humans, plants, or animals)
• Type of disease they produce
• Target cell or tropism (e.g., T helper cells for HIV)
• Immunological or antigenic properties
15.
16. BACTERIOPHAGES
• Special type of viruses that primarily infect bacteria
• They are similar to other viruses in that: 1) they are obligate
intracellular parasite; 2) they are similarly shaped like other
viruses; and 3)they may also be classified based on the type
of nucleic acid they possess
• They play a role in the acquisition of virulence factors of
certain bacteria (e.g., diptheria toxin of Corynebacterium
diphtheriae), as well as in the transfer of genetic material
from one bacterium to another. ( as in transduction)
17.
18. CHECKPOINT!
1.When –ssRNA virus enters the host it will
immediately translated into protein. (T/F)
2.Capsid is a protein (T/F)
3.DNA virus have both + and – ssDNA. (T/F)
19. BACTERIA
• Prokaryotic cells with majority
having an outer covering called
the cell wall that is composed of
peptidoglycan
• They possess both DNA and RNA
• Possess a nucleoid instead of a
true nucleus, smaller ribosomes,
and lack mitochondria
20.
21. BACTERIA MAY BE BROADLY CATEGORIZED
INTO
1. Gram-negative bacteria with cell wall (e.g.,
Escherichia coli)
2.Gram-positive bacteria with cell wall (e.g.,
Staphylococcus aureus)
3.Acid-fast bacteria with lipid-rich cell wall (e.g.,
Mycobacterium tuberculosis)
4.Bacteria without cell wall (e.g.,Mycoplasma)
22. STAINING
• Simply means coloring the microorganisms with a dye that
emphasizes certain structures
• Stains are salts composed of positive and a negative ion
• The color of the so- called basic dye is in the positive ion
• In acidic dyes is the negative ion
• Examples of basic dyes are crystal violet, methylene blue, and
safranin
• Negative staining, preparation of colorless bacteria against a
colored background
• Examples of acid dyes are eosin and nigrosin
23. THREE KINDS OF STAINING TECHNIQUES
1. Simple stain
• Aqueous or alcohol solution of a single basic dye
• To highlight the entire microorganisms
• Mordant, a chemical that is added to the solution to intensify
the stain
• Example of simple stains are methylene blue, carbolfuchsin,
gentian violet, and safranin
2. Differential stain
• React differently with different kinds of bacteria
• Examples are gram stain and acid-fast stain
24. DIFFERENTIAL STAIN
A. Gram stain
• It divides bacteria into two large
groups
• Bacteria that retain the color after the
alcohol has attempted to decolorize
them are classified as gram-positive
• Bacteria that lose the dark violet or
purple color after decolorization are
classified as gram-negative
27. THREE KINDS OF STAINING TECHNIQUES
B. Acid-fast stain
• Identify members of bacteria belonging to the genera
Mycobacterium and Nocardia
• The red dye carbolfuchsin is applied to a fixed smear
• Acid-fast bacteria remain red
• Non-acid fast bacteria take up the counterstain and appear blue
3. Special Stains
• Use to color and isolate specific parts of microorganisms, such as
endospores and flagella, and to reveal the presence of capsule
28. ACID-FAST STAINING
• Ziehl–Neelsen staining is a bacteriological stain used to
identify acid-fast organisms, mainly Mycobacteria. It is named
for two German doctors who modified the stain: the
bacteriologist Franz Ziehl (1859–1926) and the pathologist
Friedrich Neelsen (1854–1898).
• The Kinyoun method or Kinyoun stain (cold method),
developed by Joseph J. Kinyoun, is a procedure used to stain
acid-fast species of the bacterial genus Mycobacterium. It is
a variation of a method developed by Robert Koch in 1882.
29.
30.
31. 6 Classical Gram (+) Bacteria
2 cocci
a. Staphylococcus
b. Streptococcus
4 bacilli
-Produce spores (2)
a. Bacillus
b. Clostridium
Do not produce spores
a. Corynebacterium
b. Listeria
Gram (-) Bacteria
• Diplococci
• Spirochetes
32. CHECKPOINT!
1. The plural form of bacterium is BACTERIAS (T/F)
2. The cell wall of bacteria is composed of CAPSID (T/F)
3. What is the usual mordant used in gram staining?
33. FUNGI
• Eukaryotic cells with an outer surface
composed mainly of CHITIN
• Their cell membrane is made up mostly
of ergosterol
• Possess both DNA and RNA
• They possess a true nucleus that is
enclosed by a nuclear membrane and
mitochondria that function for ATP
production
• Fungal ribosomes are larger than
bacterial ribosomes (80 Svedberg unit)
34. BACTERIA FUNGI
Cell Type Prokaryotic; Unicellular Eukaryotic; Unicellular or Multicellular
Role in Ecosystem Can be both producers and
decomposers
Mainly decomposers
Optimal pH Neutral pH (6.5-7.0) Slightly acidic (4.0-6.0)
Cell structure No true nucleus and membrane bound
organelles
Possess true nucleus and membrane-
bound organelles
Main component of cell wall Peptidoglycan, except in archaebacteria Chitin
Sterols in cell membrane Absent except in Mycoplasma Present
Mode of nutrition Heterotrophic, chemoautotrophic,
photoautotrophic, aerobic, anaerobic,
facultative anaerobic
Heterotrophic; majority aerobic and
facultative anaerobe
Reproduction Binary fission Sexual and asexual spores
35. PROTOZOA
• These are also eukaryotic cells that have an outer surface
called pellicle
• Unicellular organisms that usually divide through binary
fission
• Majority exist in 2 morphological forms –cysts and
trophozoites
• The infective stage is the cyst while the pathogenic stage is the
trophozoite
• Possess both DNA and RNA as well as other cellular features
seen in typical eukaryotic cells
36.
37. ALGAE
• Eukaryotic organisms whose outer
surface consists primarily of cellulose
• Described as plant-like organisms
• Do not produce disease in humans
• Important source of food, iodine, and
other minerals
• Diatoms are unicellular algae that
inhabit fresh- and salt water
38. • Their cell wall contains silicone dioxide that may be utilized in
filtration systems, insulation and as abrasives
• Dinoflagellates are also unicellular algae that are important
members of the phytoplankton group.
• They contribute greatly to the oxygen in the atmosphere and
serve as important links in the food chain
• They are also responsible for what is known as red tide
• These small organisms produce a powerful neurotoxin which,
when ingested in significant amounts, is responsible for the
potentially fatal disease called paralytic shellfish poisoning
39. ALGAE PLANTS
Taxonomic Classification Kingdom Protista Kingdom Plantae
Cellular structure Unicellular, multicellular or
colony-forming
Multicellular
Photosynthetic Yes Yes
Energy source Carbon dioxide Carbon dioxide
Storage form of energy Starch Starch
Vascular system Absent Present
Habitat Mostly water Mostly rooted to the ground
Composed of roots, stems,
and leaves
No Yes
Method of reproduction Both asexual and sexual Asexual and Sexual
40. CELL TYPE
Column A Column B
1. Produce by meiosis and
mitosis
A. Prokaryotic
2. With 70S ribosomes B. Eukaryotic
3. Do not have membrane
bound organelles
4. DNA associated histones
5. Has true nucleus surrounded
by nuclear membrane
41. Column A Column B
6. Obligate intracellular parasite a. Bacteria
7. Outer covering made up of chitin b. Viruses
8. Possess only one type of nucleic acid c. Fungi
9. Capable of photosynthesis d. Protozoa
10. Unicellular parasite e. Algae
11. Include bacteriophages
12. Reproduction is through sexual and asexual spores
13. Outer surface consists primarily of cellulose
14. Possess chlorophyll
15. Use carbon dioxide as energy source
43. BACTERIA
• Coccus (pl. cocci) –
spherical or round shaped
organisms
• Bacillus (pl. bacilli) – rod-
shaped organisms
• Spiral-shaped or curved –
comma shaped
44.
45. Cocci
• Diplococci – arrange in pairs
• Streptococci – in chains
• Staphylococci –in clusters
• Tetrad – in groups of 4
• Octad- in groups of 8
46.
47. ENVELOPE STRUCTURES
1. GLYCOCALYX
• Outermost covering of some bacteria
• It is a gelatinous substance that is
located external to the cell wall
• Capsule
• Slime layer
• Serves to protect the organism from
dehydration
• Indicative of the virulence of the
organism
48. ENVELOPE STRUCTURES
2. Cell wall
• Sometimes called murein sacculus
• Principal component is peptidoglycan
• Provides rigid support and gives shape to the
bacteria
49. SPECIAL COMPONENTS OF GRAM(+) CELL WALLS
1. Teichoic acids –comprise major surface antigens of
gram-positive organism and can elicit antibody response
• Function for the attachment of the organism to host cell
• These also provide tensile strength to gram(+) bacterial
cell walls
2. Polysaccharides- include neutral sugars such as
mannose, arabinose, rhamnose and glucosamine
-it also include some acidic sugars such as glucuronic acid
and mannuronic acid
50.
51. SPECIAL COMPONENTS OF GRAM(-) CELL WALLS
1. Outer membrane –bi-layered structure where the inner leaflet is composed
of lipopolysaccharides (LPS)
-it has special protein channels
-LPS has a complex glycolipid called lipid A, responsible for endotoxin
activity
-The inner core is a polysaccharide made up of repeat units
-This repeat unit is called the O antigen
2. Lipoprotein-functions to anchor the outer membrane to the peptidoglycan
layer and stabilizes the outer membrane
3. Periplasmic space –a fluid-filled space between the outer membrane and the
inner plasma membrane
-It contains enzymes
52. ACID-FAST CELL WALL
• Possess an outer layer that is lipid-rich
• Composed of large amount of waxes that are
known as myolic acids
• Hydrophobic
