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Formation of Twins

 
 
15.5

Formation of Twins
 
 
Types of twins Identical twins 
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cord
Embryo division Divide into two
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Siamese twins
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cors
Embryo division Incomplete division
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Fraternal twins
Fertilisation 2 ovum fertilised by 2 sperm
Zygote formation Formed from 2 different zygote
Placenta Each has their own placenta and umbilical cords
Embryo division Not divide into two
Umbilical cords 2
Gender Same/different sex
Genetic constitution Different
Physical characteristics Different
Fingerprints Unique (different)
 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of pandai.

Formation of Twins

 
 
15.5

Formation of Twins
 
 
Types of twins Identical twins 
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cord
Embryo division Divide into two
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Siamese twins
Fertilisation 1 ovum fertilised by 1 sperm
Zygote formation Formed from 1 zygote
Placenta Share one placenta but have their own umbilical cors
Embryo division Incomplete division
Umbilical cords 2
Gender Same sex
Genetic constitution Identical
Physical characteristics Identical
Fingerprints Unique (different)
 
 
Types of twins Fraternal twins
Fertilisation 2 ovum fertilised by 2 sperm
Zygote formation Formed from 2 different zygote
Placenta Each has their own placenta and umbilical cords
Embryo division Not divide into two
Umbilical cords 2
Gender Same/different sex
Genetic constitution Different
Physical characteristics Different
Fingerprints Unique (different)
 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of pandai.
Chapter : Sexual Reproduction, Development and Growth
Topic : Formation of Twins
Form 4 Biology
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