Morphological organization and cell structure of Micro-organisms.

Here is a ppt to enable you to revise the 5 basic sectors of micro-organisms. Suggested for brief information and revision

1. Morphological organization
and Cell structure:
Bacteria, Algae, Fungi, Protozoa, Viruses.
WinonaMariaCarvalho
FY, BSc in Biotechnology
20-8030
BIC102 General Microbiology

2. Bacteria
“Bacteria are unicellular organisms belonging
to the prokaryotic group where the organisms lack
a few organelles and a true nucleus”.

3. The bacteria diagram given below
represents the structure of bacteria
with its different parts.
The cell wall, plasmid, cytoplasm
and flagella are clearly marked in
the diagram
Structure of Bacteria

4. Structure of Bacteria
The structure of bacteria is known for its simple body design. Bacteria are single-
celled microorganisms with the absence of the nucleus and othercellorganelles; hence,
they are classified as prokaryotic organisms.
They are also very versatile organisms, surviving in extremely inhospitable
conditions. Such organisms are calledextremophiles.

5. Extremophiles are further categorized into various types based on the types of environments they
inhabit:
•Thermophiles
•Acidophiles
•Alkaliphiles
Another fascinating feature of bacteria is their protectivecellwall, which is made up of a special
protein called peptidoglycan. This particular protein isn’t found anywhere else in nature except in the
cell walls of bacteria.
•Osmophiles
•Barophiles
•Cryophiles

6. But few of them are devoid of this cell wall, and others have a third protection layer
called capsule. On the outer layer, one or more flagella or pili is attached, and it
functions as a locomotory organ. Pili can also help certain bacteria to attach
themselves to the host’s cells. They do not contain any cell organelle as in animal
or plant cell except for ribosomes.
Ribosomes are the sites of protein synthesis. In addition to this DNAthey have
an extra circular DNAcalled plasmid. These plasmids make some strains of
bacteria resistant to antibiotics.

7. Classification of Bacteria
Bacteria can be classified into various categories based on their features
and characteristics. The classification of bacteria is mainly based on the
following:
•Shape
•Composition of the cell wall
•Mode of respiration
•Mode of nutrition

8. 1.Shape

9. 2.Composition of the Cell Wall

10. 3. Mode of Nutrition
4. Mode of Respiration

11. Reproduction in Bacteria
Bacteria follow an asexualmode of reproduction,called binary fission. A
single bacterium divides into two daughter cells. These are identical to the parent
cell as well as to each other. Replication of DNA within parent bacterium
marks the beginning of the fission. Eventually, cell elongates to form two
daughter cells.
The rate and timing of reproduction depend upon the conditions like
temperature and availability of nutrients. Bacterial reproduction is strictly
asexual, but it can undergo sexual reproduction in very rare cases.

12. Genetic recombinationinbacteriahas
the potential to occur through
conjugation, transformation, or
transduction. In such cases, the
bacteria may become resistant to
antibiotics since there is variation in the
genetic material (as opposed to asexual
reproduction where the same genetic
material is present in generations)

13. Useful Bacteria
1.Convert milk into curd –Lactobacillus or lactic acid bacteria
2.Ferment food products –Streptococcus and Bacillus
3.Help in digestion and improving the body’s immunity system –
Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria
4.Production of antibiotics, which is used in the treatment and prevention
of bacterial infections –Soil bacteria

14. Harmful Bacteria
There are bacteria that can cause a multitude of illnesses. They are
responsible for many of theinfectiousdiseaseslike pneumonia, tuberculosis,
diphtheria, syphilis, tooth decay. Their effects can be rectified by taking
antibiotics and prescribed medication.

15. Algae
Algae are the simplest multicellular plants.
Some are unicellular eg.Chlamydomonas

16. 1.Pant body:known as Thallus and they are avascular
2.Habitat:usually aquatic, either freshwater or marine and some are terresterial.
3.Algae are eukaryotic thallophytes.
4.Algae are photoautotrophs.
5.Storage form of food:Starch
6.Reproduction:Algae reproduce either by vegetative, asexual or sexual method
7.Vevetativemethod:fragmentation, hormogonia
8.Asexual spore:zoospores, aplanospores, hypnospores, akinetes, azygospore
9.Sexual method:isogamous, anisogamous, and oogamous gametic fusion
Characteristics

17. Classification of Algae
On the basis of photosynthetic pigments algae classified into three classes.
1.Chlorophyceae (green algae)
2.Phaeophyceae(brown algae)
3.Rhodophyceae (red algae).

18. 1. Chlorophyceae (Green algae)
•It is the largest class of algae
•They are commonly known as Green Algae.
•Photosynthetic pigments:They possesses chlorophyll a, chlorophyll b and
small amount of β-carotenoids.
•The chloroplasts shows various shape ie. Spiral shape inSpirogyra, cup
shaped inChlamydomonas, star shaped inZygnema, girdle shaped
inUlothrix
•Habitat:Mostly freshwater (Spirogyra,Oedogonium,
Chlamydomonas,Volvox, etc), some are marine (Sargassum,Laminaria, etc)
and some are parasitic (Polysiphonia, Harvevella, Cephaleuros)

19. •Distribution:they are cosmopolitan in distribution
•They are unicellular as well as multicellular.
•Each cell is eukaryotic
•Thalllus:their body structure, shape and size varies.
•Examples:Chlamydomonas:unicellular free living
•Volvox: colonial form
•Spirogyra:multicellular, unbranched filamentous form
•Ulva: multicellular, parenchymatous form

20. •Storage form of food:Starch
•Pyrenoidsstores starch
•Cell wall has two layer:outer layer composed of pectoseand
inner layer is composed of cellulose
•Reproduction:vegetative, asexual and sexual method
•Vegetative :fragmentation
•Asexual:asexual sopre(akinete, aplanospore, azygospore)
•Sexual:isogamous, anisogamous, oogamous type gametic fusion

21. 2. Phaeophyceae(Brown algae)
•Pheophyceaeare commonly known as brown algae
•Photosynthetic pigments:They possesses brown colored
photosynthetic pigments fucoxanthin and β-carotenoids in
addition to chlorophyll a and c.
•Habitat: They are almost marine, very few are fresh water
•Thallus:they are multicellular brown algae. No unicellular and
colonial (motile or non-motile) brown algae till known.

22. •Storage form of food:laminarin starch, manitol(alcohol) and
some store iodine also.
•Reproduction:vegetative, asexual and sexual methods
•Vegetative: fragmentation.
•Asexual: asexual spores (motile zoospores).
•Sexual: isogamous or oogamous type gametic fusion.

23. 3. Rhodophyceae (Red algae)
•Rhodophyceae are commonly known asRed Algae
•Photosynthetic pigments:They possesses Red colored
photosynthetic pigments r-phycocyanin and r-phycoerythrin
along with chlorophyll a, d, xanthophyll and β-carotenoid
•Habitat:They are aquatic, mostly marine. Some are
freshwater e.g.Batrachospermum.
•Thallus:Red algae show a variety of life forms-

24. •Examples: Unicellular-Porphyridium,
•multicellular-Goniotrichum,
•Parenchymatous-Porphyra,
•unicellular colonies-Chroothece,
•Storage form of food:Florideanstarch and floridosidessugar.
•Reproduction:vegetative, asexual and sexual mode
•Vegetative:fragmentation
•Asexual reproduction:non-motile spores( akinete, aplanospore,
azygospore)
•sexual reproduction:Oogamous.

25. Fungi
Fungi are eukaryotic organisms that include microorganisms
such as yeasts, mouldsand mushrooms.
These organisms are classified under kingdom fungi.

26. Structure of Fungi

27. The structure of fungi can be explained in the following points:
•Almost all the fungi have a filamentous structure except the yeast cells.
•They can be either single-celled or multicellular organism.
•Fungi consist of long thread-like structures known as hyphae. These hyphae
together form a mesh-like structure called mycelium.
•Fungi possess acell wallwhich is made up of chitin and polysaccharides.
•The cell wall comprises protoplast which is differentiated into other cell parts
such as cell membrane, cytoplasm, cell organelles and nuclei.
•The nucleus is dense, clear, with chromatin threads. The nucleus is
surrounded by a nuclear membrane.

28. Characteristics of Fungi
•Fungi are eukaryotic, non-vascular,non-motile and heterotrophic organisms.
•They may be unicellular or filamentous.
•They reproduce by means of spores.
•Fungi exhibit the phenomenon of alternation of generation.
•Fungi lack chlorophyll and hence cannot perform photosynthesis.
•Fungi store their food in the form of starch.
•Biosynthesis of chitin occurs in fungi.
•The nuclei of the fungi are very small.

29. •The fungi have no embryonic stage. They develop from the spores.
•The mode of reproduction is sexual or asexual.
•Some fungi are parasitic and can infect the host.
•Fungi produce a chemical called pheromone which leads to sexual
reproduction in fungi.
•Examples include mushrooms, moulds, yeast.

30. Classification of Fungi
1.Based on Mode of nutrition
•Saprophytic–The fungi obtain their nutrition by feeding on dead organic substances.
Examples: Rhizopus,Penicillium and Aspergillus.
•Parasitic–The fungi obtain their nutrition by living on other living organisms
(plants or animals) and absorb nutrients from their host.
Examples: Taphrina and Puccinia.

31. •Symbiotic–These fungi live byhavinganinterdependentrelationship
association with other species in which both are mutually benefited.
Examples: Lichens and mycorrhiza.
Lichens are the symbiotic association between algae and fungi.
Here both algae and fungi are mutually benefited as fungi provide shelter for
algae and in reverse algae synthesis carbohydrates for fungi.

32. 2. Based on Spore Formation
1. Basidiomycetes:
•Sexual spore are produced externally on a basidium
•Sexual spore are known as basidiospore
•Asexual reproduction occurs by budding, fragmentation or conidia
formation
•They are commonly called as mushroom group
•Hyphae are generally septated
•Examples:Amanita, Agaricus, Filobasidiella

33. 2.Ascomycetes:
•Sexual spore produced within a sac like structure called
ascus.
•Sexual spore are called ascospore
•Asexual reproduction occurs by single celled or multi celled
conidia
•Ascomycetes are also known as sac mycetes.
•Hyphae are generally septated
•Examples:Saccharomyces, Arthroderma, Gibberella

34. 3. Zygomycetes:
•Sexual spore are known as Zygospore
•Zygospore is formed by fusion of two similar cell.
•Asexual reproduction occurs by sporangiospore
•Hypaheare generally aseptated.
•Examples: Rhizopus, Mucor, Basidiobolus, Conidiobolus

35. 4.Deuteromycetes:
•No sexual stage is present
•Deuteromycetes are also known as fungi imperfecti.
•Asexual reproduction occurs by means of conidia.
•Most of the human and animal pathogens are present in this class.
•Examples:Candida, Cryptococcus, Trichophyton, Epidermophyton,
Histoplasma

36. Protista
The term ‘Protista’ is derived from the Greek word “protistos”,
meaning “the very first“.These organisms are usually
unicellular and the cell of these organisms contains a nucleus
which is bound to the organelles.

37. Characteristics
•Kingdom:Protista.
•They are known as acellular or non-cellular organism. A protozoan body
consists of only mass of protoplasm, so they are called acellular or non-cellular
animals.
•Habitat:mostly aquatic, either free living or parasitic or commensal
•Grade of organization:protoplasmic grade of organization. Single cell
performs all the vital activities thus the single cell acts like a whole body.
•Body of protozoa is either naked or covered by a pellicle.

38. •Locomotion:Locomotory organ are pseudopodia (false foot) or cilia or
absent.
•Nutrition:Nutrition are holophytic (like plant) or holozoic (like
animal) or saprophytic or parasitic.
•Digestion:digestion is intracellular, occurs in food vacuoles.
•Respiration:through the body surface.
•Osmoregulation:Contractile vacuoles helps in osmoregulation.
•Reproduction:
•Asexual reproduction is through binary fission or budding.
•Sexual reproduction is by syngamy conjugation.

39. Classification
1.Amoeboid protozoans –Mostly found in water bodies, either fresh or saline.
They have pseudopodia (false feet) which help to change their shape and in
capturing and engulfing food. E.g. Amoeba
2.Flagellated protozoans –As the name suggests, the members of this group have
flagella. They can be free-living as well as parasitic. E.g. Euglena
3.Ciliated protozoans –They have cilia all over their body which help in
locomotion as well as nutrition. They are always aquatic. E.g. Paramecium
4.Sporozoans –These organisms are so-called because their life cycle has a spore-
like stage. For example, the malarial parasite, Plasmodium.

40. Virus
Viruses are infectious agents that
replicate inside the body of a host

41. Characteristics
•Viruses size, ranging between 30-50 nm.
•They usually lack a cell wall but are surrounded by a protective protein
coating called the capsid.
•It can be seen as a genetic element and is characterized by the combined
evolution of the virus and the host.
•They contain either RNA or DNAas the genetic material. Viruses mainly
depend on a host to deliver the complex metabolic machinery of prokaryotic
oreukaryotic cellsfor propagation.

42. •The main task of the virus is to carry its DNAor RNA genome to the host cell,
which then can be transcribed by the host cell.
•The viral genome is packed in a capsulated symmetric protein.
•The protein associated with nucleic acid or nucleoprotein produces the
nucleocapsid with the genome.
•They are considered both as living and non-living things.
•These viruses are inactive when they are present outside of host cells, but become
active within host cells.
•These viruses cause several infections and reproduce within the host cell by using
the enzymes and raw materials.

43. Structure

44. Classification
Viruses can be classified primarily on their phenotypic characteristics,core
content, chemical composition, capsid structure, size, shape, genome
structure and modes of replication.

45. 1. Presence of nucleic acid
DNA virus
The virus, having DNAas its genetic material. There are two different
types of DNAvirus
Single-stranded (ss) DNAvirus: e.g. Picornaviruses,
Parvovirus,etc.
Double-stranded (ds) DNAvirus: e.g. Adenovirus, Herpes virus, etc.

46. RNA virus
The virus, having RNA as its genetic material. There are two different types of
RNAvirus
Double-stranded (ds) RNAvirus: e.g. Reovirus, etc.
Single-stranded (ss) RNA virus.
It is further classified into two
Positive sense RNA (+RNA) and negative sense RNA (-RNA).
Poliovirus, Hepatitis A, Rabies virus, Influenza virus are examples of
single-stranded RNA virus.

47. 2. Structure or symmetry
•Complex virus.
E.gPoxvirus
•Radial symmetry virus.
E.g.Bacteriophage
•Cubical or icosahedral symmetry shapedvirus.
E.g. Reovirus, Picornavirus
•Rod or Spiral shaped or helical symmetry virus.
E.g. Paramyxovirus, orthomyxovirus

48. 3.Replication properties and site of replication
•Replication within the cytoplasm of the host cell.
E.g. All RNAviruses except the Influenza virus.
•Replication within the nucleus and the cytoplasm of the hostcell.
E.g. Influenza virus, Poxvirus, etc.
•Replication within the nucleus of the hostcell.
All DNA viruses except Pox virus.
•Replication of the virus through the double-stranded DNA intermediate.
E.g. All DNA viruses, Retrovirus and some tumourcausing RNAvirus.
•Replication of the virus through a single-stranded RNAintermediate.
E.g. All RNAviruses except Reovirus and tumour-causing RNA viruses.

49. 4.The host range
Based on the type of host, there are four different types of viruses:
Animal viruses
These viruses infect by invading the cells of animals, including humans. Prominent
examples of animal viruses include the influenza virus, mumps virus, rabies virus,
poliovirus, Herpes virus, etc.
Plant viruses
These viruses infect plants by invading theplant cells.Well-known examples of plant
virus include the potato virus, tobacco mosaic virus, beet yellow virus, and turnip yellow
virus,cauliflower mosaic virus, etc.

50. Bacteriophage
The virus which infects bacterial cells is known as bacteriophage. There are many
varieties of bacteriophages, such as DNAvirus, MV-11, RNA virus,λpage, etc.
Insect virus
The virus which infects insectsis known as Insect virus, also called the viral
pathogen ofinsects. Theseviruses are considered as a powerful biocontrol agentin
the landscape of modern agriculture. AscovirusvirionsandEntomopoxvirus,
are best examples for insect virus.

51. 5.Mode of transmission
•Airborne infections –Transmission of the virus through the air into the respiratory tract.
E.g. Swine flu, and Rhinovirus.
•Fecal oral route–Transmission of the virus through the contaminated water or food.
E.g. Hepatitis A virus, Poliovirus, Rotavirus.
•Sexually transmitted diseases –Transmission of the virus through sexual contacts with the
infected person. E.g. Retrovirus, human papillomavirus, etc.
•Transfusion-transmittedinfections-Transmission of the virus through the blood
transfusion.
E.g. Hepatitis B virus, Human Immunodeficiency Virus, etc.
•Zoonoses-Transmission of the virus through the biting of infected animals, birds, and
insects to human. E.g. Rabies virus, Alpha virus,Flavivirus, Ebola virus, etc.

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