ULOTHRIX

Question 1

How many pyrenoids per chloroplast?

Answer 1

one to several

Question 2

Motile or non-motile?

Answer 2

Non-motile

Question 3

How does it look?

Answer 3

Threadlike with a single row of cylindrical cells that are attached end to end = filament

the basal cell of each filament is longer than the other cells and therefore functions as a holdfast to the substrate

Question 4

Reproduction?

Answer 4

Both asexual and sexual

Question 5

Reproduction, Asexual?

Answer 5

1. the contents of the cells condense and divide via mitosis becoming zoospores (ZS)
2. can divide one to several times before becoming ZS
3. ZS escape from the parent cell via a pore in the wall and swim and then settle on a substrate.
4. Flagella are shed and ZS divide via mitosis
5. One of the first 2 daughter cells will form the holdfast and the other one will continue to divide and form the filament

Question 6

Reproduction, Sexual?

Answer 6

1. Contents of the cell divide via mitosis
2. Up t 64 ZS, each with 2 flagella will be produced and then will escape.
3. these will function as gametes and pair with gametes from other filaments forming zygospores.
4. Thick walls will form around the zygospores, dormancy is established.
5. Wall is shed, zygospores divide, meiosis, ZS formed, these undergo mitosis after they settle on a substratum
6. gametes are identical in size and appearance = isogamy