Cleavage

Question 1

Cleavage

Answer 1

cell division that occurs without overall growth of embryo. Cells get smaller in size, divide quickly (once per day)

Question 2

Blastomere

Answer 2

one cell of the embryo during the cleavage stage

Question 3

when does cleavage occur?

Answer 3

from fertilization to implantation (in womb)

Question 4

stages of cleavage

Answer 4

2/4/8 cell, Morula

Question 5

2,4,8 Cell stage

Answer 5

division occurs in ~1 day. Corona radiata is no longer present. 3, 5 cell stage can exist. releases early pregnancy factor.

Question 6

early pregnancy factor

Answer 6

molecule used to test for pregnancy. protects conceptus from mother’s immune system. Circulates mother’s blood. Different from what home pregnancy test detects

Question 7

morula

Answer 7

stage of embryo with 8-16 cells. latin for mulberry

Question 8

blastocyst

Answer 8

embryo after blastulation

Question 9

trophoblast

Answer 9

outer layer of cells. forms part of placenta

Question 10

inner cell mass (of blastocyst)

Answer 10

inner ball of cells. forms conceptus proper, amnion, and umbilical cord

Question 11

Hatching

Answer 11

release of the blastocyst from the zona pellucida. allows embryo to implant to womb, because zona pellucida isn’t sticky, but embryo is.

Question 12

How does the embryo know when to hatch?

Answer 12

it hatches after 5 days

Question 13

Parental Imprinting

Answer 13

functions that always come from the father only or from the mother only

Question 14

paternal parental imprinting

Answer 14

causes placental development

Question 15

maternal parental imprinting

Answer 15

embryo proper development

Question 16

parthenote

Answer 16

oocyte activated without sperm. only has maternal dna. develops similar to blastocyst, but with no inner cell mass

Question 17

hydatidiform moles

Answer 17

activated oocyte without dna from oocyte nucleus. maternal dna lost in polar body. only sperm dna is present. creates a tumor. does not mature into an organism.

Question 18

x chromosome inactivation

Answer 18

the “turning off” of one x chromosome. Only occurs in females. Prevents double dose of X products. Chromosome turned off occurs randomly, but permanently

Question 19

x,y chromosome

Answer 19

determines genter. Male: XY, Female:XX. Y chromosome has fewer genes.