week 6 - algae

Question 1

four groups of algae

Answer 1

Red, green, brown, and gold
- Brown algae are all multicellular (=seadweed) and are MACROscopic
o Arose through secondary endosymbiosis

NB: ‘blue-green algae’ are not algae but bacteria (cyanobacteria)

Question 2

red algae

Answer 2

• Rhodophytes
• Phototrophs mostly found in marine environments
• Some unicellular, most multicellular (seaweeds – AGAR)
• Colour due to phycoerythrin
  o An accessory pigment that masks green
   Blue light further in water
• Chlorophyll a
• Phycobiliproteins
  o Light harvesting pigments from cyanobacteria
   Phycoerythrin

Question 3

green algae

Answer 3

• Chlorophytes
• Some unicellular, many multicellular
• Typically freshwater
• Chlorophyll a and b
• No phycobiliproteins
• Evolutionarily very important as:
  o The ancestor of plants
  o An insight into the evolution of multicellularity (Volvox)

Question 4

golden algae

Answer 4

• Also know as chrysophytes and derives from secondary endosymbiosis
• Mostly unicellular marine/fresh water phototrophs
• Some are chemoorganotrophs
  o Feed by membrane transport or phagocytosis)
• Most are motile with unequal flagella
• Colour from fucoxanthin carotenoid pigment
• Chlorophyll c
• No phycobiliproteins

Question 5

algae:
multicellularity

Answer 5

• Chlamydomonas is a single celled, flagellate green alga
• Volvox is a colonial alga
  o Up to 50, 000 flagellate cells in a gelatinous hollow ball
• Daughter colonies bud into the middle

Question 6

lichens

Answer 6

• Lichens are symbiotic communities of two microbes
• Partner one is a fungus that typically cannot live independently
• Partner two (phototroph) is a cyanobacterium or a green algae
• Commonly found as pioneer species
• Can live in harsh environments
• Also air quality indicators