Representative Gastrulation Patterns (Oligolecithal) -sea urchins

Question 1

true or false
not all oligolecithal eggs will gastrulate the way sea urchin eggs did

Answer 1

True

Question 2

true or false
oligolecithal eggs has single layer of cells surrounding a blastocoel

Answer 2

true

Question 3

true or false
the flattening out of cells where there indents a little bit (invagination) happens in the area of animal pole

Answer 3

False (happens in vegetal pole)

Question 4

in the gastrulation patterns of oligolecithal eggs, _______ will separate from the rest of the layer because they will go inside; start to grow in; form the skeleton of the organism

Answer 4

micromeres

Question 5

what keeps the oligolecithal egg in a ball shape?

Answer 5

hyaline layer

Question 6

true or false
in the representative gastrulation pattern of sea urchin oligolecithal egg, micromeres joins with hyaline layer

Answer 6

False (micromeres separate from hyaline layer)

Question 7

micromeres will extend to the other side forming the __________

Answer 7

primitive gut

Question 8

true or false
Micromeres function by extending and pulling other cells to reach the other side

Answer 8

True

Question 9

what guides micromeres as they extend and pull other cells to reach the other side?

Answer 9

Fibronectin (guide cells as they migrate)

Question 10

In oligolecithal egg gastrulation pattern, what happens to the area where the invaginated part came from?

Answer 10

In oligolecithal egg gastrulation, where there’s a limited amount of yolk concentrated at one pole, the invagination typically occurs at the animal pole. The area where the invaginated part came from is known as the blastocoel, which forms between the ectoderm and the remaining yolk mass. This process establishes the basic germ layers – ectoderm, mesoderm, and endoderm – essential for further embryonic development.

Question 11

What happens to the migrating cells when they reach the other side?

Answer 11

they contribute to the formation of the germ layers. The cells continue their movement, with some forming the endoderm, others the mesoderm, and those remaining on the surface becoming the ectoderm. This layering process is crucial for the subsequent development of different tissues and organs in the embryo. The precise fate of the migrating cells depends on their location and interactions during gastrulation.