Chapter 36, Problem 23A

Summary Introduction

To write:

Comparison and contrast the division of inner cell mass in identical twins aand normal development.

Introduction:

One fertilized egg (ovum) divides into two babies with precisely the same genetic material, for the development of identical and monozygotic twins. Two eggs (ova), fertilized with two sperms, produce two genetically distinct offspring in the form of fraternal or dizygotic twins.

Explanation of Solution

The blastocyst inner cell mass consists of two types of cells: epiblast and the placenta, and chorion, and the amniotic membranes which form the mature organ. Embryonic stem cells are cells that are to grow into the completed embryo. Whereas twins form the same after a single sperm has fertilized an egg and it separates into two zygotes. This develops at the earliest embryonic stage where the zygote is only a cluster of multiple cells.