very short and simple explanations of some concepts under general characters of algae. in this PDF you will find introduction of algae, about the cell structure, nutrition of algae and algal flagella.
3. What is algae?
• Algae can be defined as the small autotrophs
that fail to show any cellular differentiation &
their sex organs are either unicellular or
multicellular.
• The study of algae is called Algology or
Phycology.
• Phycology is made up of two words, Phycos
and logy. Where phycos means
seaweeds(grow by their salves) and logy
means study.
• First introduced by Linnaeus in 1754.
4. Eukaryotic algal cells are characterised by presence of well organised nucleus
and membrane bound organelles like plastids, mitochondria and Golgi bodies.
An intermediate form called mesokaryotic occurs in Dianophyceae which shows
both eukaryotic (nucleus with nuclear membrane & chromosomes) and
prokaryotic characters (basic proteins are absent).
Some do not has true cell wall Ex: euglena.
Motile flagella possess a pigmented spot known as eye-spot or stigma
(swimming).
Cell wall is with mixed carbohydrates and substances like alginic acid, fucoidin,
fucin & hemicelluloses present.
In this cell Mitochondria, Golgi complex, Endoplasmic reticulum are present.
5.
6. Flagella is Found in all algae except Rhotophyceae.
The main function of flagella is motility.
They are of 2 types
1) Whiplash: Possess smooth surface.
2) Tinsel: Covered by fine filamentous appendages called as mastigonemes or
flimmers.
Tinsel is further divided into three types
1) Pantonematic-mastigonemes arranged in two opposite rows or radially.
2) Pantocronematic - Pantonematic flagellum with a terminal fibril.
3) Stichonematic - mastigonemes develop only on one side of the flagellum
7.
8. Algae can be either autotrophic or Hetrotropic. Most are photoautotrophic.
Photo autotrophic and synthesis their own food from carbon dioxide and water.
Aquatic forms obtain carbon dioxide and water by diffusion and osmosis.
Aerials obtain water from damp substratum and carbon dioxide from air.
They also synthesis oil and proteins from carbohydrates.
