RHODOPHYTA . Occurrence And General Structure Of Rhodophyta

This slide is about Occurrence And General Structure Of Rhodophyta.

1. RHODOPHYTA BY MUHAMMAD USMAN ZAKI

2. RHODOPHYTA O ccurrence A nd G eneral S tructure O f Rhodophyta

3. Define “Rhodophyta can be defined as the division of the lower plants which comprises of red algae .”

4. Explain Rhodophyta are a sub-group of algae, the red algae. Even though they are called “ red algae ” not all species are necessarily red . Their pigmentation can vary depending on where they are living . Rhodophytes in deeper waters are typically a dark red, almost black color, while those in medium depths are bright red. In shallow areas, the algae can appear more green than red. Some species even have pink or purple coloring . Their color comes from an accessory pigment phycoerythrin that is found inside of the algae, giving its reddish color. The phycoerythrin absorbs other colors and reflect the red. The Rhodophyta characterized by the accessory photosynthetic pigments phycoerythrin , phycocyanin and allophycocyanins arranged in phycobilisomes . The absence of flagella and centrioles.

5. Occurrence of Rhodophyta Rhodophyta are aquatic organisms that exist in both freshwater and marine habitats, although mostly marine . They are found in tropical, temperate, and cold-water environments . Rhodophyta tend to live at greater depths of water than Charophyta and Chlorophyta . Red algae are found around the world, from polar to tropical waters , T hey are commonly found in tide pools and in coral reefs.

6. Most Rhodophyta are multicellular organisms, although a few are unicellular or colonial. T hey have no chloroplast and endoplasmic reticulum . Rhodophyta have unstacked thylakoids in plastids. Some species have pit connections between cells. Rhodophyta are autotrophic, obtaining and storing floridian starch from photosynthesis General Structure of Rhodophyta

7. The reserved food material in red algae in the form of solid carbohydrate called floridian starch. Central vacuole is present in except few red algae. A single nucleus is present in the center of cell which is located as spherical . Cell membrane is the between the cell wall and cytoplasm. Mitochondria is present in red algae.

8. Cell wall Cell wall of red algae is microfibrillar framework Microfibrillar framework which is composed of cellulose. Unicellular red algae have an amorphous matric of sulfated polysaccharide with out cellulose surrounding the cells. The amorphous polysaccharides occur between the cellulose microfibrils in the rest of the red algae. Two largest group of amorphous mucilages are the agars and carrageenans. These mucilage may constitute up to 70% of dry weight of cell wall. Cuticle present outside the cell wall.

9. chloroplast In simple rhodophycea the chloroplast with central pyrenoid is present. But in all other rhodophycea the chloroplast is discoid. Thylakoid singly occur inside the chloroplast. Phycobilin pigments are presented on the surface of thylakoid in the form of phycobilisomes. Chlorophyll a , d phycoerythrin and phycocyanin pigments are present in red algae.