1. Red Algae

2. What is Red Algae? It is the largest phyla of algae
Its scientific name is rhodophyta
It is made up of eukaryotic cells without flagella and centrioles, unstacked thylakoids, and no chloroplast ER.
Unstacked thylakoids in plastids

3. Pigment
Red algae is red because of the presence of red phycoerythrin. It is often the dominant pigment.
It reflects red light and absorbs blue light.
Some red algae have very little phycoerythrin, and may appear green or bluish.

4. Depth
Because blue light penetrates water to a greater depth than light of longer wavelengths, these pigments allow red algae to photosynthesize and live at greater depths than most other algae.

5. Food In Asia, red algae is an important source of food.
It has a high vitamin and protein content.
It is easy to cultivate, which began in Japan more than 300 years ago.
Red algae can be dried up to make nori

6. Products
One type of red algae, coralline, secretes a calcium carbonate skeleton in the same way that corals do. They have contributed to reef structure even more so than corals.
A closer look at coralline algae: o&feature=related

7. Review Questions Why is red algae red?
What is the significance of coralline red algae?
What does coralline red algae secrete?
Red algae reflects what and absorbs what?
Why is red algae able to grow at greater depths than other algae?
What about red algae makes it a valuable food source?
Answers on next slide...

8. Review Question Answers
Because of the presence of red phycoerythrin
It contributes a lot to reef structure
Calcium carbonate
Red algae reflects red light and absorbs blue light.
Because blue light penetrates water to a greater depth than light of longer wavelengths
It has a high vitamin and protein content and also easy to cultivate