BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers

BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers

BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers: BSc is a three-year program in most universities. Some of the universities also offer BSc Honours. After getting enrolled for BSc, there are certain things you require the most to get better grades/marks in BSc. Out of those, there are BSc Study Material, BSc Sample Model Practice Mock Question Answer Papers along with BSc Previous Year Papers. At you can easily get all these study materials and notes for free. Here in this post, we are happy to provide you with BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers.

BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers
BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers

Index for BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers

BSc Economic Importance of Algae Question Answer Papers: Page 1

Economic importance of Algae as a primary Source of food Energy: Page 2

Economic importance of Agar-Agar: Page 3

Economic importance of Carrageenin: Page 4

Economic importance of Alginates: Page 5

Economic importance of Funori: Page 6

Economic importance of Red Algae: Page 7

Ques 1. Discuss briefly the Economic Importance of Algae.


Ques. Write an essay on the economic importance of Algae.

Ans. Algae is well known to human beings from prehistoric times. Many Algae (seaweeds) are used by human beings for food, the manufacture of iodine, and some other purposes in ancient times. In present days phycology (the Study of Algae) has made great advances. Extensive research is now being done in phycology and many workers are trying to find out the food value of algae, their importance in industries, and importance in agriculture, etc.

The importance of the role played by algae in the world is becoming more appreciated each day because of the increased utilization many of them are extremely valuable to man. The value of algae, for a human being, may be discussed as follows:

(1) Algae as food

A large number of species of Algae are used as a source of food by human beings. They are rich in carbohydrates, inorganic substance and vitamins. Vitamins A, B, C, D and E are the main constituents of these plants. Poryphyra tenera is very popular and eaten throughout Japan. Kombu is another product of algae Laminaria which is used in Japan as standard food. Porphyra, Rhodomenia, Qedogonium, Spirogyra, Chaetophora, etc. are the chief sources of food. Ulva (sea lettuce) is also used by man as food.

In recent years green algae Chlorella has drawn the attention of phycologists. The percentage of protein in this algae is too much or even more than any other vegetable or egg. It is said to contain all vitamins from A to D. Many psychologists, particularly in Japan, China and America are busy in finding out its food value. Chlorella is a future hope of modern world as food supplement.

It is cultivated industrially in Japan, America and China. It’s rate of growth is very rapid Chlorella is rich in protein and carbohydrates. It yields about 30% protein, 15% lipids, 30% carbohydrates, and 5% ash Chlorella protein may compared with animal protein except for lower content in methionine. Chlorella has large number of vitamins. In the modern


age with space conquest by man schedules of long flights lasting several months, method has to be developed to feed astronauts. In man flights Chlorella culturing tanks as a source of food and oxygen has been suggested by aeronautical research laboratories. Witsch (1959) stated vitamin B in Chlorella is equal to that of lemon juice. This algae is also used to decorate pastries, sandwiches, rice, fish, cakes and jelly cakes in Japan. Agar-Agar is also used in the preparation of ice-creams and jellies. Gelidium, Gracillaria, etc. algae are the chief sources of agar-agar.

Another algae Rhodomenia plamata is chewed like tobacco in Scotland “Hair vegetable” is eaten in China and Algae Nostoc commune is one of its constituents. From algae Macroystis we obtain colloidal gel which is used in many ways in the preparation of ice-creams in America.

A minute green algae Chlorella has also been found as a food source of human beings and animals. It has nearly 5% protein which is about 4 to 5 times the protein contents of wheat.

Many algae are used as fodder for animals like sheep, goat, cattle, etc. in New Zealand. 

The different types of aquatic algae also serve as a main source of food for aquatic animals specially fishes. Fishes constitute a very important food for human beings. Thus, we also get food from algae through fishes.

In India sea weeds are not so extensively used for food as in Japan, etc. through the Indian coasts are rich in sea weed. Edible sea weeds found on Indian coasts are Rhodymenia, Laurencia, Acanthophora, Padina, Sargassum, Codium, Caulerpa, etc. These provide a very good supplement for a well balanced diet because of their higher mineral contents.

(2) Algae as Fodder

Certain brown algae such as Fucus, Laminaria and Ascophyllum are used a stock feed for sheep and cattles. There are industries for processing them into commercial feed in Ireland and Scotland. This algal fodder is quite nutritious due to the high-vitamin and mineral contents. It has been recorded that the milk of cow which are eating such fodder’ is richer in fat contents as compared to other type of fodder eater cows Similarly her eating this sea weed produce eggs rich in Iodine.

Rhodymenia is common cattle food in Japan and used as a cow feed.

Planktonic algae form the major food for fishes and other aquatic animals. 

(3) Algae in Industry

Diatoms (An algae)-prepare diatomaceous earth and is extensively used in sugar refineries and soap manufacture. It is also helpful in cement industry, in the manufacture of dynamite, rubber and blotting paper, etc. It is also used in insulation of boilers, blast furnaces and at various other places where a very high temperature (1000oC) is required.

Algins extracted by boiling algae in washing soda solution and rollers of type writers are prepared from it. Japanese prepare artificial wool from Sargassum. Carrageenin, which is produced from algae Chondrus, is used by dairymen to prevent settling of ground chocolate in chocolate milk.

Agar-Agar which is obtained from algae like Gelidium, etc. is used in sizing of textile. Algae Chondrus and Careragaenium which yields mucilage is used in the manufacture of flat hats as stiffening agent. It has the properties of agar and therefore used as ingradient of cosmetics, shaving-creams, shoe polish and shampoos. In India the steps for manufacture of agar were taken up by Board of Scientific and Industries Research, Travancore. 

Various red algae like Laminaria yields Iodine. Several sea weeds also yield bromine, acetic acid and acetone. 

(4) Algae in Agriculture or Algae in Nitrogen Fixation

The presence of mucilage in most of the members of Myxophycea helps in the development and better nourishment for nitrogen fixing bacteria. Some of them like Anabaena, Nostoc, etc. are themselves able to utilize and fix atmospheric nitrogen, thus increasing soil fertility. It has been seen that some members of myxophyceae were able to fix 20 lbs of atmospheric nitrogen per acre in rice field. The increase in the field of rise was also promoted to 15% to 25%.

Prof. R. N. Singh (1961, 74) has drawn attention towards the importance of blue green algae in the Nitrogen fixation which makes the fields fertile. Anabaena, Aulosira, Cylindrospermum, Tolypothrix, Micrococcus, Nostoc, Phromidium, etc. are some important algae in general which the important in nitrogen fixation. 

Usar oil (these are highly alkaline soils, which are non fertile soils) become fertile due to some blue green algae. This process known as Soil reclamation. 

In the present days with the help of never techniques, better strains with high ability for nitrogen fixation are being evolved and cultivated to bulk. Such blue green algal materials are being distributed to farmers as seed material for innoculating new fields. Such a technique known as “algalization” was first introduced in Japan and is now being worked out effectively in India also. 

Algae may act as source of growth substances. It has been reported by Shukla (1967) that presoaking Rice seed treatments with Phormidium tenue result in stronger intensively green plants, profuse tillering and increased height. This also results in multiple rice yields. The protein contents of grains, of treated plants also increases.

(5) Algae as Manure or Fertilizer

Sea weeds are extensively utilized as manures because they are rich in potassium phosphorous, trace elements and growth substance. These sea weeds are either rotted in fields or composed with organic materials. These manure enrich the fields in mineral nutrients and helps in soil binding, in breaking down clays and promoting good crumb formation. In Irish Fucus is collected and used as manure. The dried mud of ponds is usually used as manure in crop fields due to high contents of blue green algae which is used as a good fertilizer. Lithothamion and Lithophyllum are important algae used as sea weed manure.

(6) Medicinal uses of Algae

The green unicellular algae Chlorella yields an antibiotic known as chlorellin. This antibiotic extracted from Chlorella is crystalline and stable at 120°C. With an average composition of carbon (77.3%), hydrogen (16.6%) and oxygen (19.99%), it has a marked effect on gram positive and gram negative bacteria.

Presence of Chara and Nitella algae in a pond causes the death of mosquito larvae, thus helping in control of malaria to little extent.

Extracts of Cladophora, Lyngbya and certain other algae also reported to kill strains of Pseudomonas and Cynobacterium. They also exhibit antiviral activity.

Several algae such as Ulva, Fucus, Sargassum, etc. are used as vermifungus in different countries of the world.

(7) Algae in Sewage Disposal Or Algae in Purification of Water

The purification of sewage is done to make organic matter of the sewage harmless and inoffensive. Complete purification of the organic content can be accomplished by only biological processes requiring abundant supply of oxygen. The algal photosynthesis is in unexpensive and natural method of meeting the oxygen requirement for the sewage purification.

Sewage consists of water borne wastes of community. It also has a number of faceal and other anaerobic bacteria which may be pathogenic. Usually the sewage is disposed to rivers, lakes, etc. and this is proved to be very harmful for health of man. A recent and interesting development in the biological treatment of sewage is the use of natural phenomenon of algal photosynthesis which supplies the oxygen required.

The growth of certain unicellular algae like Chlorella, Chlamydomonas, Scendesmus and Euglena help in the bacterial decomposition of sewage by providing oxygen, in addition, they recover the mineral nutrients from sewage which would otherwise have been lost.

(8) Algae in Biological Research

There are certain aspects of algae that contribute to basic, biological research.

Our advancing knowledge of the chemistry of photosynthesis and of other aspects of metabolism is based largely on studies of unicellular algae such as Chlorella. This is because of the relative ease and convenience of maintaining large uniform population in small space under rigidly controlled conditions.

Certain algae like Acetabularia, Valonia and Nitella show a great success in studies on morphogenesis, nuclear function, nuclear cytoplasmic relationship and ionic exchange with the environment.

Some algae like Chlamydomonas and some desmids are being used in genetical studies. Chlamydomanas was the first haploid organism on which successful hybridization was accomplished.

The basic biological phenomenon of sexuality, its control and initiation, and mating type comparibility are under intensive investigation in such favourable organisms as Chlamydomonas and Oedogonium. Such organisms may be grown readily in culture under controlled conditions and thus are suitable systems for study of basic sexual phenomenon.

Thus, from the above discussion it is clear the algae is of great importance for human being. 


(1) Algal pollution (water blooms)

Water blooms formation takes place by the super abundance of “microscopic free floating algae in a pond, tank, lake, rivers, etc. The blooms soon develop in such quantities that large areas of waters are covered with thick layer that resembles to green paint or thick pea soup. Many of the algae produce unpleasant smells to the water. These water blooms pollute the water and water become completely useless for man and domestic animals. Water blooms also cause the water poisoning.

Algae decay, and the decayed by products are poisonous to fishes and some other animals. Some of the algae liberate poisonous toxins in the water, making the latter unsuitable for some of the inhabiting animals. Microcystis aeuginosa produces a toxin which is highly toxic to animals which ingestion this algae (Hughes et al. (1958). Gorham (1964) and Loeblich (1975) worked on the algae which are toxic to animals. According to Stephens (1948), Microcystis toxica contains one of the most potent and destructive liver poison.”

Deaths of fishes, shell fishes, some other aquatic animals and sometimes even human being are known because of ingestion of dinoflgellates (species of Gymnodinium, Gonyalax and Pyrodinium). Because of the dinoflagellates, “it has been estimated that in eight months one-half billion fish were killed in the Gulf of Mexico alone” (Prescott, 1969). Algae may also cause the death of fishes and other animals by suffocation.

Algae destroy the weapons, house walls, boats, etc. They causes the death of fishes animals and even of man.

BSc 1st Year Botany Economic Importance of Algae Sample Model Practice Question Answer Papers

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