A detailed information on algae and protozoa.

1. ALGAE & PROTOZOA
SONA . S
MSc BIOCHEMISTRY

2. ALGAE
i. The term “algae” was first introduced by Linnaeus in 1753.
ii. Primitive and simplest division of plant kingdom.
iii. Algae are Eukaryotic, chlorophyll bearing, photosynthetic with thalloid
plant body.
iv. Autotrophic in nutrition
v. Study of algae is called phycology
vi. They are essential for aquatic ecosystems and contribute
significantly to oxygen production and nutrient cycling.
vii. They do not possess the specialized reproductive structures
commonly found in higher plants.
viii. Unicellular or multicellular
ix. Cells may be uninucleated or multinucleated
x. Motile due to the presence of flagella or cilia

3. OCCURENCE;
 Algae are ubiquitous in distribution
 Found in places with sufficient sunlight, moisture, and simple nutrients to
sustain.
HABITAT
AQUATIC TERRESTRIAL
FRESHWATER FORMS
Eg;Spirogyra,
Chlamydomonas,
and Volvox.
MARINE FORMS
Eg; Sargassum,
Laminaria and
Polysiphonia
MOIST SOIL
Eg; Fritschiella and
chlorella
LITHOPHYTIC ALGAE
Eg; Nostoc

4. Plankton;
• They are free floating microscopic life that inhabit the upper layer of
water
• Lacks the capability to swim against water currents
• There are two types of plankton;
• Plays pivotal role in nutrient cycle, oxygen production and serve as a
base for food web
PHYTOPLANKTON
Eg; diatoms, dinoflagellates, and
cyanobacteria
ZOOPLANKTON
(include crustaceans, copepods, larvae of fishes
and shellfishes

5. Phytoplankton Zooplankton

6. STRUCTURE OF ALGAE;

7. • Cell wall is mainly made of cellulose
• Presence of chlorophyll and other photosynthetic pigments like
fucoxanthin and phycoerythrin.
• Chloroplast; may be cup shaped/star shaped or layered.
• Pyranoid; helps in the concentration of enzymes,
particularly RuBisCO involved in carbon dioxide fixation
during photosynthesis. It is surrounded by starch grains
which helps in storage of starch.
• Eyespot or stigma ; It is a light-sensitive organelle that
helps the cell to detect and respond to light.

8. CLASSIFICATION
Classes Common
name
Major pigments Stored food Cell wall Examples
Chlorophyceae Green algae Chlorophyll a, b Starch Cellulose Sea Lettuce,
Spirogyra, Volvox,
Chlorella
Phaeophyceae Brown algae Chlorophyll a, c,
fucoxanthin
Mannitol,
Laminarian
Cellulose and algin Sargassum, Kelp,
Ectocarpus
Rhodophyceae Red algae Chlorophyll a, d,
phycoerythrin
Floridean
starch
Cellulose, pectin,
polysulphate esters
Irish moss,
rhodella, Laver
(nori)

9. EXAMPLES OF GREEN ALGAE;
Sea lettuce
Spirogyra
Chlorella
Volvox

10. EXAMPLES OF BROWN ALGAE
Sargassum
Kelps
Ectocarpus

11. EXAMPLES OF RED ALGAE;
Laver (nori)
Irish moss
Rodella

12. REPRODUCTION ;
Binary fission
Eg; Chalmydomonas
Fragmentation
Eg; Spirogyra
Spore formation
Eg; Ulva
ISOGAMOUS
Eg; Ulothrix, Spirogyra
ANISOGAMOUS/HETEROGAMOUS
Eg; Fucus
OOGAMOUS
Eg; Odogonium, Volvox
SEXUAL MEANS ASEXUAL MEANS

13. ECONOMIC IMPORTANCE;
1. Food and Nutrition;
Phytoplankton serve as an important food source for aquatic animals.
Certain algae, such as seaweeds (e.g., nori, kelp), are consumed as
direct food products. They are rich in vitamins, minerals, and proteins.
Algae can also serve as fodder for livestock.
Some species of microalgae are rich in omega-3-fatty acids (DHA, EPA)
Spirulina, Chlorella and Irish moss are used as SCP
Algae serve as the primary link in aquatic food chains.
Diatoms, filamentous green algae, and blue-green algae are often part
of fish diets.
Tilapia mossambica thrives on a filamentous algae (Scenedesmus)
which is served as a daily meal

14. 2. Species like Chlamydomonas, Scenedesmus, Chlorella,
and Euglena are used in sewage treatment plants.
3. Coralline algae, play a role in limestone deposition.
4. Algal products like Algin, Alginic acid, Carrageenan and Agar
are used as a gelling agent in food,stabiliser or emulsifier in ice
creams, binder in toothpastes. Agar is used as solidifying agent in
microbial culture media. Algin is used for immobilisation/
encapsulation of cells or enzymes
5. Algae contain a variety of bioactive compounds with potential
pharmacological effects. Phycobiliproteins, found in red and
blue-green algae, exhibit anti-inflammatory and antioxidant
properties.
6. Main Oxygen producers of aquatic system

15. PROTOZOA
• The word protozoa comes from a Greek word protozoon meaning
“First Animal”
• Protozoa are unicellular and eukaryotic
• Most protozoa are heterotrophic, meaning they obtain their
food by ingesting organic matter. They may feed on bacteria,
algae, or other microorganisms.
• Study of eukaryotic protists called protozoology
• Live freely may be parasitic or symbiotic
• Protozoa can be aerobic or anaerobic, and some even thrive
in extreme environments like hot springs.
• Many protozoa form resting cysts to survive dry conditions.

16. OCCURRENCE;
Protozoa are found in a wide range of environments, i,e. from
terrestrial to aquatic habitats.
Many protozoa inhabit freshwater ecosystems such as ponds,
lakes, rivers, and streams
Protozoa are abundant in marine environments, from coastal
areas to deep-sea habitats.
Certain protozoa form endosymbiotic relationships with other
organisms. For example, some protozoa inhabit the guts of
termites and aid in the digestion of cellulose.
Protozoa can be parasitic, living inside the bodies of other
organisms. Examples include Plasmodium spp. causing malaria

17. MORPHOLOGY
Size range from 5- 250µm in diameter
Cell shape; spherical, elongated, amoeboid (irregular shape), or
even complex structures.
Cell organelles are highly specialised for feeding, reproduction and
locomotion.
Many protozoa has multiple nuclei (2 dissimilar nuclei)
• Macronucleus –involved in metabolic activities and regeneration (Eg; stentor)
• Micronucleus - involved in reproductive activity.
Cytoplasam
• Contains submicroscopic protein fibrils which helps in contractibility
• Differentiated into
i. Ectoplasam - helps in movement, protection and feeding
ii. Endoplasam - houses mitochondria, nucleus, and food

18. Flagella: Some protozoa possess whip-like flagella for
locomotion. These can be single or multiple and are used for
swimming.
Cilia: Hair-like structures called cilia may cover the surface of
certain protozoa. Cilia beat in coordinated waves, enabling
movement and food capture.
Pseudopodia: Amoeboid protozoa move and capture food by
extending temporary projections of the cell membrane called
pseudopodia.
The outer covering of protozoa may include a flexible pellicle
Some protozoa, especially ciliates, have a specialized structure
called an oral groove and a cytostome for the intake of food
particles
Presence of Contractile vacuoles which are involved in
osmoregulation, regulating water content within the cell.

21. REPRODUCTION;
SEXUAL REPRODUCTION ASEXUAL REPRODUCTION
BINARY FISSION;
Eg;amoebas,
flagellates, and
ciliates.
MULTIPLE FISSION;
Eg;Plasmodium
BUDDING;
Eg;flagellates and
ciliates
CONJUGATION;
Eg; Paramecium
SYNGAMY;
Eg; Monocystis

22. Plasmodium Monocystis

23. ECONOMIC IMPORTANCE;
i. Certain protozoa form symbiotic relationships with termites,
aiding in the digestion of cellulose.
ii. Ciliated protozoa helps in treating wastewater by consuming
bacteria and organic matter, helping to purify water before it is
released into the environment.
iii. Protozoa are a natural component of aquatic ecosystems and
serve as a food source for various aquatic species in aquaculture
systems.
iv. Skeletal deposits of marine protozoa (such
as Foraminifera and Radiolaria) form deposits at the sea
bottom.These deposits are used as filtering agents, chalk, and
abrasives.Over time, these deposits transform into limestone
rock, which serves as a building material
v. Protozoan skeletal deposits are often associated with oil deposits,
aiding in locating oil reserves.

24. REFERENCE;
1. Pelczar, M. J., E. C. S. Chan, and N. R. Krieg. Microbiology. Fifth
edition, Tata Mcgraw-hill Publishing Company Ltd., New Delhi
(2004).
2. Willey, J. M. Prescott, Harley, and Klein's Microbiology-7th
international ed.: McGraw-Hill Higher Education, 2008

25. THANK YOU