lecture 13 (green algae)

Question 1

what type of environment do you find green algae in?

Answer 1

freshwater, terrestrial surfaces, snow, symbiotic associations (eg. lichens, sea slugs), some nearshore marine

Question 2

describe a Chlamydomonas cell

Answer 2

unicellular green alga with two flagella, lives in freshwater, cup-like chloroplast and rigid cell wall.

Question 3

name one Unique characteristic of green algae

Answer 3

stores starch inside the chloroplasts, isokont flagella in multiples of 2

Question 4

what body types are found in green algae?

Answer 4

unicellular flagellate/non-flagellates, motile/non-motile colonies, branched/unbranched filaments, parenchymatous forms, multinucleate coenocytes

Question 5

what are the types of cell coverings in green algae?

Answer 5

naked, cellulose wall, organic scales, or calcified

Question 6

are there intercellular connections in some green algae? what are they called?

Answer 6

some have plasmodesmata (cytoplasmic intercellular connections)

Question 7

describe the zygotic life cycle of Chlamydomonas

Answer 7

zygotic meiosis: (N) vegetative phases release (N) gametes which fertilize and become 2N zygotes which undergo meiosis to release two N vegetative phase juvenilles

Question 8

describe the sporic life cycle of Ulva

Answer 8

sporic meiosis: N gametophytes release gametes (N) which fuse and fertilize to become a 2N zygote. the zygote becomes a 2N sporophyte which undergoes meiosis to release N spores that germinate into gametophytes

Question 9

can green algae be found in symbiotic relationships? provide 2 examples

Answer 9

yes, with fungi to form lichen, and in sea anemones and sea slugs

Question 10

describe chlorophytes vs streptophytes

Answer 10

chlorophytes: major lineage of greens, marine, freshwater and terrestrial, closed mitosis, cytokinesis (furrowing and microtubular structure), presence of plasmodesmata in chlorophycea
streptophytes: land plants and closest green algal relatives, freshwater and terrestrial habitats, open mitosis, cytokinesis (furrowing and cell plate formation), presence of plasmodesmata

Question 11

briefly provide characteristics of each one of the five major groups within green algae

Answer 11

prasinophytes: marine, variable mitosis, variable photorespiratory enzymes, zygotic meiosis, flagellar and body scales common
trebouxiophyceae: no scales, glycolate dehydrogenase photorespiratory enzymes, mitosis is semi-closed/non-persistent spindle, freshwater/terrestrial, zygotic meiosis
ulvophyceae: body and flagellar scales, glycolate dehydrogenase photorespiratory enzymes, closed mitosis with persistent spindle, marine or terrestrial, zygotic meiosis or AOG, or gametic meiosis.
chlorophyceae: scales occur rarely, glycolate dehydrogenase photorespiratory enzymes, closed mitosis with non-persistent spindle, freshwater or terrestrial, zygotic meiosis
streptophyte: body and flagellar scales usually present, photorespiratory enzymes are glycolate oxidase and catalase in peroxisome, open mitosis with persistent spindle, freshwater or terrestrial, zygotic meiosis