Algae

occurrence and physiological characteristics of algae and its use in cosmetic field and other industries.

1. ALGAE By:- Khushbu shrivastava

2. INTRODUCTION The term algae was proposed by linnaeus in 1753 but he had used this term for those organisms which we call bryophytes now a days. A.L.de Jussieu (1789) was first to use it for those organisms which we now believe to be algae. Algae is a term that describes a large and incredibly diverse group of eukaryotic, photosynthetic life forms. These organisms do not share a common ancestor and hence, are not related to each other (polyphyletic) Algae can be multicellular or unicellular. Most of the multicellular algae placed in kingdom PLANTAE and few unicellular algae are placed in kingdom PROTISTA. PLANTAE - blue green algae, giant kelp and brown algae PROTISTA - diatoms, euglenoids , Dinoflagellates The branch of botany dealing with the study of algae is known as phycology or algology. It is derived from the greek word phykos which means ‘alga’ or ‘ seaweed ’.

3. Occurrence of algae Algae are commonly presumed to be occurring in water and moist places but algae are found in a variety of habitats. The common places of occurrence of algae are as follows:- AQ UATIC ALGAE :- Fresh water forms- are found in water of low salinity such as in ponds, lakes, rivers, ditches etc. Cladophora,, vaucheria, chara and some algae found in slow running water while spirogyra, chlamydomonas, hydrodictyon and volvox are found in stagnant water. Marine forms- algae found in seawater are called marine algae. Such algae grow in water of high salinity.marine algae can be macroscopic and very large in size eg:- Macrocystic (70m) and nereocystis (100m), viva, enteromorpha, sargassum etc.

4. Occurrence of algae 2. TERRESTRIAL ALGAE :- Algae growing on moist soil surfaces, stones and rocks are terrestrial algae. The algae growing on surface of soil are called saprophytes. The algae growing under the surface of soil are called cryptophytes. Some terrestrial algae grow on moist walls and barks of trees, these algae absorb carbon dioxide and water from atmosphere. Eg:- Fritschiella , vaucheria, chlorella and oscillatoria.

5. Occurrence of algae. 3. LITHOPHYTIC ALGAE :- algae growing on surface of rocks and stones are lithophytic eg:- N ostoc, Gloeocapsa. 4. HALOPHYTIC ALGAE: - algae growing in water of high concentration of salt lakes are halophytic algae eg:- Chlamydomonas ehrenbergii and Dunaliella. 5. THERMOPHYTIC ALGAE :- the algae grow in water of high temp. Where other plants forms cannot grow, some blue-green algae are capable of growing at very high temp. Eg:- Oscillatoria, T ere piriformis , Heterohotmogonium, etc. 6. CRYOPHYTIC ALGAE :- algae occurring in snow and ice are crophytic algae. These algae impart special color to the snow due their pigments. Red snow - Haematococcus Nivalis Green snow- Chlamydomonas yellowstonensis 7. EPIPHYTIC ALGAE :- algae growing on other algae and plants are called epiphytic algae eg:- polysiphonia,oedogonium are found growing on other algae 8. EPIZOIC ALGAE :- algae growing on other animals are called epizoic algae eg:- Cladophora crisposa grows on snails, Stigeoclonium grows on gills of fishes. 9. ENDOPHYTIC ALGAE :- algae growing inside other plants are called endophytic algae eg:- nostoc i s found in thallus of anthoceros. 10. ENDOZOIC ALGAE :- algae found inside the body of animals are endozoic algae eg:- Zoo chlorella is found in hydra and sponges, some blue-green algae found in respiratory tract of animals. 11. PARASITIC ALGAE :-some algaes can be found as parasites on plants and animals eg:- cephaleuros is found on leaves of tea. 12. SYMBIOTIC ALGAE :-some algae of chlorophyceae and cyanophyceae are found in symbiotic association with other plants. Lichens are symbiotic association with algae and fungi. 13. PLANKTONS: - algae growing on surface of water and found as free floating on surface of water are called planktons. When planktonic algae grow fast and increase enormously in number these algae form water blooms.

6. General characteristics of algae. It consist of chlorophyll and other pigments for carrying out photosynthesis. (photoautotrophs) Most algae require a moist or watery environment; hence, they are ubiquitous near or inside water bodies. Anatomically, they are similar to another major group of photosynthetic organisms – the land plants. However, that is where the differences end as algae lack many structural components typically present in plants, such as true stems, shoots, and leaves. Furthermore, they also do not have vascular tissues to circulate essential nutrients and water throughout their body. they possess specialized structures and cell-organelle s,like centrioles and flagella, found only in animals. Reproduction in algae occurs in both asexual and sexual forms. Range in size from microscopic to single celled organisms to large seaweed.

7. General characteristics of algae. 8. Algae are free-living, although some can form a symbiotic relationship with other organisms. 9. Cell wall is thin and rigid and require carbondioxide and light as their principal source of energy. 10. Motile algae such as euglena have flexible cell membrane called periplasm. 11. Cell wall of many algae are surrounded by a flexible gelatinous outer matrix. 12. Discrete nucleus is present and inclusion like starch granules, oil droplets and vacuoles are present. 13 . Chloroplasts may occur one, two or many per cell they may be ribbon like, bar like, net like or as discrete discs.

8. Morphology of algae The eukaryotic algae cell is surrounded by a thin rigid cell wall. The cell wall of the algae is made up of cellulose, hemicellulose,mucilage,pectin and other substances like alginic acid, fucoidan ,fucin,calcium carbonate,silica etc. Some algae contain a stout and strong plasma membrane The nucleus of eukaryotic algae is well organised. The nucleus is surrounded by a double-layered nuclear membrane. The inner side of the membrane is occupied by a chromatin reticulum embedded in a matrix called karyolymph . The outer side of the nuclear membrane is conti­nuous with the endoplasmic reticulum. The nucleus contains one, two or more nucleoli or endosomes, the number varies in different algae. The eukaryotic algae contain membrane-bound organelles such as chloroplasts, mitochondria , golgi apparatus, endoplasmic reticu­lum and, in some cases, eye spot or stigma. The eye-spot or stigma is a motile vegetative and reproductive cell and contain pigments spots in anterior,middle or posterior part of the cell Chloroplast is a double-membrane structure containing photosynthetic pig­ments. A disc like structure is formed from the internal lamellar system which are stacked together to form grana. This disc is a sac or vesicle and known as thylakoid, which are encloses an inner thylakoid space.

9. FLAGELLA (motility) Motile vegetative or reproductive algal cells perform their locomotion or movement by using thread-like protoplasmic appendages known as the flagella. Mainly two types of flagella have been identified in algae such as; A.Whiplash or Acronematic is a hairless and smooth surfaced-.flagella B.. Tinsel or Pleuronematic contain one or more rows of lateral fine filamentous hairs called mastigonemes or flimmers. There are also other types of flagella such as; Pantonematic: masti­gonemes are arranged in two opposite rows. Pantoacronematic: When Pantonematic flagella contain a terminal fibril is known as pantoacronematic. Stichonematic: contain one-sided masti­gonemes.

10. Reproduction in algae ASEXUAL REPRODUCTION It is a process of formation of progeny without the union of cell or nuclear material. Some unicellular algae reproduce asexually by any of these 3 process :- Fragmentation Zoospores Binary fission SEXUAL REPRODUCTION. Sexual reproduction is characterized by the process of meiosis, in which progeny cells receive half of their genetic information from each parent cell. A sexually reproducing organism typically has two phases in its life cycle. In the first stage, each cell has a single set of chromosomes and is called haploid, whereas in the second stage each cell has two sets of chromosomes and is called diploid When one haploid gamete fuses with another haploid gamete during fertilization, the resulting combination, with two sets of chromosomes, is called a zygote . a diploid cell directly or indirectly undergoes a special reductive cell-division process (meiosis) During meiosis the chromosome number of a diploid sporophyte is halved, and the resulting daughter cells are haploid.

11. Life-cycle of algae

12. classification of algae Based on seven major divisions. Nature and properties of pigment. Chemistry of reserve food products. Morphology of flagella. Morphology of cells and thalli. Life history reproductive structure and methods of reproduction. Food storage substance. Cell wall composition.

13. DIVIDED INTO 9 PHYLA Phylum Rhodophyta Phylum Xantho Phycophyta Phylum chrysophycophyta Phylum phaeo phycophyta Phylum bacillariophyta Phylum euglenophyta Phylum chlorophycophyta Phylum crypto phycophyta Phylum pyrrophycophyta

14. PHYLUM RHODE PHYCOPHYTA +4000 species of RED ALGAE The red algae are commonly found in tropical marine locations. Unlike other algae, these eukaryotic cells lack flagella and centrioles. they grow on solid surfaces including tropical reefs or attached to other algae. Their cell walls consist of cellulose and many different types of carbohydrates. These algae reproduce asexually by monospores (walled, spherical cells without flagella) that are carried by water currents until germination. Red algae also reproduce sexually and undergo alternation of generation. Red algae form a number of different seaweed types. Smaller than brown algae and often found at a depth of 200 meters. Contain chlorophyll a and d as well as phycobilins which are important in absorbing light that can penetrate deep into the water. Have cells coated in carrageenan which is used in cosmetics, gelatin capsules and some cheeses. Red algae GELIDIUM is the one from which AGAR is made.

15. 2. PHYLUM XANTHO PHYCOPHYTA 450-460 species of YELLOW GREEN ALGAE Yellow green algae are the least prolific species of algae. They are unicellular organisms with cell walls made of cellulose, pectin and silica, they contain 1-2 flagella for motion. Their chloroplast lacks a certain pigment, which cause them to appear lighter in color. They usually form in small colonies of only a few cells. Yellow-green algae typically live in freshwater , but can be found in salt water and wet soil environments. Chlorophyll a,c and rarely e are present. Cellular storage product is chrysolaminarin. Flagella unequal in length. Asexual reproduction by cell division and fragmentation VAUCHERIA is a well known member of this division.

16. 3.PHYLUM CHRYSOPHYCOPHYTA 100,000+ species of GOLDEN ALGAE Golden- algae are the most abundant types of unicellular algae, 2. They are found in fresh and salt water environments. 3. Predominantly flagellates some are amoeboid 4. Chlorophyll a and c present 5. Reserve food as chrysolaminarin and their frequent incorporation of silica 6. Characteristic color due to masking of their chlorophyll by brown pigments and because of presence of carotenoid pigment. 7. Reproduction is commonly asexual but at times isogamous.

17. 4. PHYLUM PHAEO PHYCOPHYTA 1500 species of BROWN ALGAE Brown algae are among the largest species of algae, consisting of varieties of seaweed and kelp found in marine environments. All are multicellular and large (often reaching lengths of 147 ft.) Individual alga may grow to a length of 100m with a holdfast, stripe and blade. These species have differentiated tissues,including an anchoring organ, air pockets for buoyancy, a stalk, photosynthetic organs,and reproductive tissues that produce spores and gametes. Chlorophyll a and c present Some examples of brown species include sargassum weed, rockweed, and giant kelp (100 m). Used in cosmetics and most ice creams .

18. 5. PHYLUM BACILLARIOPHYTA THE DIATOMS Diatoms are found in fresh water as well as in salt water. Diatoms provide abundant food supply for aquatic animals. Chlorophyll a and c present. Shells of diatoms are called frustules. Deposits of these shells from centuries of growth are called diatomite or diatomaceous earth.

19. 6. PHYLUM EUGLENOPHYTA 1000 species of euglenoids Unicellular and motile by means of flagella Chlorophyll a and b present Have both plant like and animal like characteristics They lack a cell wall but instead are covered by a protein-rich layer called the pellicle. It consist of eyespot, flagella, and organelles (nucleus, chloroplasts, and vacuole). Reproduction by longitudinal binary fission Carry out photosynthesis in chloroplast and is facultatively autotrophic .

20. 7. PHYLUM CHLOROPHYCOPHYTA 7000 species of GREEN ALGAE Green algae mostly found in freshwater and some species can be found in the ocean. It has cell wall made up of cellulose and some species have one or two flagella. Both green algae and land plants have chlorophyll a and b as well as carotenoids and store food as starch. There are thousands of unicellular and multicellular species of these algae. Multicellular species usually group in colonies ranging in size from 4 cells to several thousand cells. For reproduction some species produce non-motile the rely on water currents while others produce zoospores with 1 flagellum for swimming to a more favorable environment Examples of green algae includes sea lettuce, horsehair algae, and dead man’s fingers.

21. 8. PHYLUM CRYPTOPHYCOPHTA Cryptomonas are biflagellate organisms Cells are slipper shaped and flattened occur singly. Some with cellulose wall others naked There are 1 or 2 plastids with or without pyrenoids. Reproduction by longitudinal cell division or by zoospores or cysts.

22. 9. PHYLUM PYRROPHYCOPHYTA Flagella are inserted in the girdle and arranged with one encircling the cell and other trailing Many are covered only by plasmalemma and in some there is a wall made of cellulose Some have series of cellulose plates with in plasmalemma termed thecal plates Dinoflagellates a diverse group of biflagellates unicellular organisms present.

23. IMPORTANCE

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