Lecture on Algae and Protists

These flashcards cover key concepts and definitions related to algae and protists, as discussed in the lecture.

What are the key pigments found in red algae and their role?

Red algae contain phycobilins, which are accessory pigments that contribute to their red color.

What is a paraphyletic group?

A paraphyletic group includes a common ancestor but does not include all descendants.

Why are protists considered paraphyletic?

Because they include the ancestor of plants, animals, and fungi, but those descendants are excluded.

Which algae were observed in the lab? Which one is considered evolutionarily advanced?

Spirogyra (green algae) and Polysiphonia (red algae) or Brown algae. Brown algae are considered more evolutionarily advanced.

What are three major reasons why we study protists?

1. They are evolutionary ancestors of plants, animals, and fungi.
2. They are major producers in aquatic food webs.
3. They play a key role in global oxygen and carbon cycles.

What is the significance of secondary endosymbiosis in diatoms and brown algae?

It is the process where a heterotrophic eukaryote engulfed a red alga and retained its chloroplast, leading to chloroplasts with four membranes.

List five products derived from algae.

1. Food (nori, kelp, spirulina)
2. Agar (from red algae)
3. Carrageenan (food thickener)
4. Alginates (from brown algae, stabilizers)
5. Biofuels/fertilizers.

What triggers sexual reproduction in Diatoms?

Sexual reproduction is triggered when diatom cells become too small after repeated asexual divisions.

What are the main components found in the cell walls of brown algae?

Cell walls are composed of cellulose and alginic acid, providing strength and flexibility.

What light-harvesting pigments are present in brown algae?

Brown algae contain chlorophyll a, chlorophyll c, and fucoxanthin, with the latter giving brown algae their characteristic color.

How did red and green algae become photosynthetic? What genetic trait was lost?

They became photosynthetic through primary endosymbiosis where a eukaryote engulfed a cyanobacterium; the trait lost from red to green algae is unknown.