Complete O/L notes biology: CHP.7 SPYROGYRA

CHAPTER SEVEN

7.0.           SPYROGYRA

7.1.            Classification of spirogyra

Kingdom: Protoctista

Phylum: Chlorophyta

Class: Chlorophyceae

Scientific name: spirogyra

Common name: spirogyra

                Spirogyra is an alga. It is green in color and the cell has a cellulose cell wall and a definite nucleus. They have chloroplast which is spiral with pyrene on it.

Spirogyra are filamentous green alga which are found in fresh water. It also has a cytoplasmic stand and large vacuole spirogyra carried out asexual production by fragmentation and sexual reproduction by conjugation.

7.2.            Habitats of spirogyra.

Spirogyra can be found in fresh water such as river ponds, ditches and slow running streams. Some may be found on moist branches or wet branches.

7.3.            Structure of spirogyra.

Spirogyra is a green filamentations alga which is slimy to the touches.

Spirogyra is the green filamentous alga which is slimy because it is covered by a gelatinous outer layer

Each cell is also covered by a cell wall of cellulose the nucleus is suspended in the middle by a cytoplasm stand. The cell has a large vacuole containing cell sap. The chloroplast is spiral and it contains paranoids.

///////////////////////////////////////diagram of spirogyra////////////////////////

7.4.            Growth in spirogyra

The spirogyra grows by increase in length but when a filament is cut into pieces, each grows into a new spirogyra filament.

7.5.            Respiration in spirogyra

Considering the fat that spirogyra has single cells in the rows, oxygen diffuses into the organism and carbon dioxide diffuses out.

7.6.            Nutrition in spirogyra

Spirogyra is green because it contains chlorophyll in the presence of carbon dioxide, mineral salt and water with energy coming from sunlight spirogyra can manufacture its own food through the presence of photosynthesis.

7.7.            Reproduction in spirogyra

Spirogyra reproduces asexually as well as sexually

7.7.1         Asexual reproduction in spirogyra

Asexual reproduction can go on by fragmentation that is breaking up of filament and after this, binary fission can go on to reproduce a new filament.

7.7.2. sexual reproduction in spirogyra

  1. Sexual reproduction is by conjugation which takes place in the following order two filaments come and lie side by side.
  2. The filaments develop production protuberances
  3. The protuberances meet and the wall between them breaks down to form a conjugation tube. The content shrinks and become round and one content flow into the other.
  4. The cell content fuse together and a zygote is formed
  5. The zygote develops a thick dark wall around the cell to form a zygote spore
  6. The zygote spore geminates become a new filament

///////////////////binary fusion///////////////////

 

 

/////////////////conjugation/////////////////////

7.8.            Economic importance of Algae

  1. It helps in the fixation of Caro dioxide during photosynthesis
  2. It releases oxygen into the atmosphere which can be used by other organism for respiration
  3. Some algae used as food
  4. Some algae are used as fertilization
  5. They are used as a source of protein for animals and human organisms of feeding
  6. Alginic acid which is extracted from algae is used as a thicker
  7. When algae overcrowd the bodies as water, they contaminate the water and cause pollution
  8. Algae are the bases of food chain
  9. Algae may grow on water on block the water for navigation.

7.9.            Differences between spirogyra and amoeba

spirogyra amoeba
It has rigid cell It has flexible cell surface membrane
The cytoplasm at the corner The cytoplasm is spread all over the cell
The vacuoles the corner The vacuoles are small and distributed
The vacuole is suspended by a cytoplasmic stand The cytoplasmic stand is absent
It is green in color showing that it contains chloroplast with chlorophyll It is colored and has no chloroplast
The cells form chains The cell is single
Since they contain chlorophyll it can manufacture their own food through photosynthesis They cannot manufacture their own food
Lacks pseudopodia for movement so it is sessile They contain pseudopodia for movement so they are motile
It has a definite shape Has an irregular shape
Have permanent organelles (cell part) Has sudo-organels. Which are formed when needed
Has one type of vacuole Have two types of vacuoles (food and contractile vacuole)
Is relatively smaller than amoeba Is relatively longer than spirogyra

 

 

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