1. ALGAE AND YEAST
JANAVI BHANDARI
MSC- FOOD AND NUTRITION
N - 2005

2. CONTENT:-
• INTRODUCTION
• SALIENT FEATURES
• STRUCTURE AND MORPHOLOGY
• REPRODUCTION
• IMPORTANCE

3. ALGAE :-
 The word algae is derived from the Latin word alga which means sea weeds.
 The general term “algae” includes prokryotic organism – cyanobacteria, also
known as blue green algae, as well as eukaryoticorganisms (all other algae
species).
 Algae are a diverse group of Aquatic organism that have the ability to
conduct photosynthesis.
 Algae are found in a range of Aquatic Habitats, both freshwaterand
saltwater.
 The study of algae is called algology or phycology.

4. SALIENT FEATURES :-
 Live in moist and aquatic habitats
 Unicellular or multicellular.
 Plant body is a Thalloid.
 Presence of chlorophyll and other photosynthetic pigments.
 Autotrophic in nutrition.
 cell maybe Uni-nucleated or multi-nucleated.
 Cell wall is rich in cellulose.
 Cell motility is due to the presence of flagella.

5. STRUCTURE :-
 They are found in a varietyof forms and sizes. They can exist as
single cells and multicellularcells.
 Lack true roots, stems and leaves, and a vascular system to
circulate waterand nutrients throughout their body.
 It is broadly divided into two main categories:-
1. Unicellular
2. Multicellular

7. UNICELLULAR :-
1. Motile:- A singlecell with flagellafor locomotion. Eg- chlamydomonas.
2. Non –motile :- A single non – motile cell carrying out all essential functions of life.
Flagellais absent. Eg- chlorella.
CHLORELLA
CHLAMYDOMONAS

8. MULTICELLULAR :-
Colony is formed by aggregation of individual cells.
1. Motile colony :- individual cells possess flagella. Eg- Vovox.
2. Non –motile colony :- individual cell in the colony lacks flagella.
3. Amorphous colony:- Numerous non- motile cells are embedded in a common
mucilaginous matrix. Eg- Tetraspora
4. Dendroid forms :- the phallus appears as tree like under microscope. Eg- Dinobryon
5. Filamentous :- cells arranged one upon the other in a definite sequence forming
filaments. Eg- Cladophora , Spirogyra
6. Heterotrichous form :- Presence of more than one type of filaments.
7. Parenchymatous forms :- Cell divisionand associated separation leads to the
formationof a parenchymarous body. Eg- Chara

9. DRAPARNALDIOPSIS CHARA
CLADOPHORA
DINOBRYON TETRASPORA
PEDIASTRUM
MULTICELLULAR ALGAE

10. REPRODUCTION :-
 Algae are capable of reproducing through asexual or
vegetative methods and via sexual reproduction.
 Asexual Reproduction involves the production of motile spores.
 Vegetative methods includes simple cell division (mitosis) to
produce identical offspring and the fragmentation of the
colony.
 Sexual reproduction involves the fusion of gametes (produce
individually in each parent through meiosis).

11. IMPORTANCE OF ALGAE :-
 Probably the most important contribution of ALGAE to our
environment is the produced oxygen through photosynthesis.
 Green algae, diatoms and cyanobacteria are the microalgae
species that are considered good candidate for the
production of biofuel.
 Algae helps to keep atmospheric carbon dioxide levels stable
by storing the gas.

12. YEAST

13. INTRODUCTION :-
 Yeasts are eukaryotic, single-celled microorganisms.
 1,500 species are currently identified(1% of all fungal species).
 A microscopic fungi consists of single oval cell that
reproduce by budding.
 They are capable of converting sugar into alcohol and
carbohydrate.

14. MORPHOLOGY OF YEAST :-
 They are single cells fungi.
 Size – generally, larger than most bacteria.
 Yeast cell lacks flagellar and other organs for locomotion.
 Cell wall is composed of thin chitinous cell wall.
 The protoplasm is surrounded by cell membrane which contain
all the usual cell organelle like ribosomes, mitochondria,
nucleus, etc.
 Vacuole is single, large and centrally located.

15. REPRODUCTION :-
 Yeast generally reproduce by asexual methods such as budding
or fusion
 Yeast lack sex organs.
 Sexual reproduction in yeast is highly variable

16. ASEXUAL REPRODUCTION - BUDDING :-
 It occurred during abundant
supply of Nutrition.
 Parent nuclieus divide and
move towards daughter cell.
 Enzymatic activities increases.
 Septum formation and bud
separates into individual cells.
 Small yeast cell are being
formed off of larger yeast cells.
This is called budding.

17. SEXUAL REPRODUCTION :-
 Sexual reproduction is very rarely
in some of the yeasts.
 Three different pattern of life
cycle found in different Genes –
1. Haplodiplobiontic life cycle
2. Haplobionticlife cycle
3. Diplobionticlife cycle

18. IMPORTANCE OF YEAST :-
1. Food industry
 Bread making – for the manufacturing of
bread, yeast is mixed with white flour.
 Fermentation alcool – breakdown of starch
and sugar by yeast into carbon dioxide and
ethyl alcohol in the presence of oxygen.
2. Use in Brewing industry
 Beer – yeast is added to malted grains and
allowed to ferment.
 Wine – yeast is naturally present on the skin’s
of grapes and can be used to naturally
ferment grape juice into wine.

19. IMPORTANCE OF YEAST :-
3. Medical use
 Lowering high cholesterol- research
showed that taking a specific red
yeast product for 2-3 months could
significantly lower“bad cholesterol“.
4. Nutrition
 Yeast is a good source of protein, B-
vitaminand minerals