Cleavage

Question 1

What is cleavage?

Answer 1

Series of cell divisions of zygote that occur without cell growth or separation

Question 2

blastomere

Answer 2

daughter cells generated from cleavage divisions

Question 3

What is a morula?

Answer 3

solid ball of cells created from early cleavage divisions

Question 4

What is a blastula?

Answer 4

hollow fluid-filled ball of cells forme as water flows osmotically towards center or morula.

Question 5

what is a blastocoel?

Answer 5

cavity formed in blastula. important for future development of organisms

Question 6

karyokinesis

Answer 6

sepearation of chronosomes into two cells

Question 7

cytokinesis

Answer 7

division of cytoplasm into 2 cells, facilitated by microfilaments

Question 8

what are the two components of cleavage?

Answer 8

karyokinesis and cytokinesis

Question 9

holoblastic cleavage

Answer 9

(complete cleavage) yolk doesn’t play much of an influential role because there isn’t much of it. Instead, cleavage can go all the way through the egg

happens in isolecithal and mesolecithal eggs

Question 10

isolecithal

Answer 10

sparce, evenly-distributed yolk

Question 11

mesolecithal

Answer 11

moderate vegetal yolk distribution, affects rate of cleavage

Question 12

meroblastic cleavage

Answer 12

(incomplete cleavage) parts of egg are not cleaved because of the large amount of yolk

happens for telolecithal and centrolecithal eggs

Question 13

telolecithal

Answer 13

dense yolk throughout most of the egg

Question 14

centrolecithal

Answer 14

yolk in center of the egg

Question 15

What is gastrulation?

Answer 15

series of movements of individual cells and sheets of cells that accomplishes at least three important developmental objectives

Question 16

accomplishments of gastrulation

Answer 16

1. Generates 3 germ layers
2. Establishes bilateral symmetry
3. Establishes new and unique cell interactions which influence future developmental events

Question 17

What process of gastrulation develops germ layers?

Answer 17

ingression

Question 18

What are cadherins?

Answer 18

family of cell-cell adhesion molecules that hold cells of blastula togehter as a sheet

Question 19

aboral

Answer 19

side of developing organism away from mouth. like dorsal (as opp. to ventral)