Lecture 20

Question 1

Define protist, algae, phytoplankton, and seaweed

Answer 1

protists
- eukaryotes that are not land plants, animals or fungi
Algae
- photosynthetic protists
Phytoplankton
- algae suspended in water
Sea weeds
- algae anchored to the substrate, structurally more complex then phytoplankton

Question 2

relationship between red and green algae

Answer 2

• same eukaryotic supergroup
• both derived from common ancestor that acquired chloroplasts thru primary endosymbiosis

Question 3

Discuss the economic importance of red algae (Rhodophyta)

Answer 3

Intertidal zone
- withstand wave action, exposure to changing humidity, temp,light, salinity
Epiphytes
- lives on brown algae
Crustose on coral leaf
- reinforce reef structure
- settling site for coral larvae

Question 4

Describe red algae chloroplasts

Answer 4

Pigments
- chlorophyll a
- phycobilins
Internal membranes
- thylakoids not stacked into granae
External membrane
- double
Storage
- stored outside of chloroplast
Cell walls
- made of microfibrils embedded in glactan and mucilage
- is continually shed
- harvested for agar and carrageenan
- some produce lignin; convergent evolution

Question 5

Discuss recent evidence that is driving new hypotheses about the closest algal
relatives of land plants.

Answer 5

Zygnematophyceae
- unicellular freshwater algae
- can live on wet rocks
- share genes with embryophyta

Question 6

describe green algae chloroplasts

Answer 6

Pigments
- chlorophyll a, b, carotenoids
Internal membranes
- thylakoids stacked into granae
External membrane
- double
Storage
- inside chloroplast