self study notes uni- to multicellular organisms

Question 1

what is the differentiation of cells that occurs in dictyoselium discoideum?

Answer 1

STALK or SPORE CELL: stalk cells help with mobility, help spores to be taken away by the wind or water; spores restart as single-celled organisms

Question 2

what are the 3 essential things that illustrate evolution of multicellular organisms?

Answer 2

1) cell-cell signaling
2) cell differentiation
3) cell death/sacrifice/apoptosis

Question 3

what is Volvox carteri and what are its characteristics?

Answer 3

Chlamydomonas = algae; they have a chloroplast where photosynthesis occurs; nucleus, eyespot to primitively detect light and flagella to swim
Volvox carteri look like a cluster of Chlamydomonas that are interacting with each other through an extracellular matrix. Their reproductive cells are called gonidia; they start cleaving and after an asymmetric cell division, smaller reproductive cells are generated with somatic cells

Question 4

what is the differentiation of Volvox carteri cells?

Answer 4

reproductive cells, Chlamydomonas-like cells, cells that survive and generate a new organism (gonidia), cells that die

Question 5

why is C.elegans suitable for genetic analysis?

Answer 5

relatively small number of cells, invariant lineage, transparent embryo, hermaphrodites

Question 6

how are the AP axis and the DV axis specified in C. elegans?

Answer 6

AP axis - by how sperm enters the body: posterior part is where the sperm actually enters the body
DV axis - by cell-to-cell interactions

Question 7

why do ducks have webbed feet?

Answer 7

they do not have apoptotic cells in between their digits, while chickens and mammals do