10.4 Mutations Flashcards
What is nondisjunction?
The failure of homologous chromosomes or sister chromatids to separate properly during cell division
Nondisjunction can result in gametes with an abnormal number of chromosomes.
What is trisomy?
A genetic condition where an individual has three copies of a chromosome instead of the normal two
An example is Down syndrome, which is caused by trisomy of chromosome 21.
What is monosomy?
A genetic condition where an individual has only one copy of a chromosome instead of the normal two
An example is Turner syndrome, which is characterized by the presence of a single X chromosome.
What is a Barr body?
An inactivated X chromosome found in the cells of females
Typically, one Barr body is present in each female somatic cell.
How does nondisjunction lead to an incorrect number of chromosomes?
By causing gametes to have an abnormal number of chromosomes, leading to conditions like aneuploidy
Aneuploidy can result in syndromes such as Down syndrome.
What happens to a zygote in case of deletion?
The zygote may lack certain genetic information, potentially resulting in developmental issues
Severity depends on the size of the deletion.
What happens to a zygote in case of duplication?
The zygote may have extra genetic material, which can lead to abnormal development or phenotypic traits
This can also affect gene expression levels.
What happens to a zygote in case of translocation?
The zygote may exhibit developmental abnormalities depending on the genes affected by the translocation
It can also lead to infertility in the parents.
Determine the type of reproductive system and the number of Barr bodies for XXX chromosomes.
Female reproductive system with 2 Barr bodies per cell
The presence of two X chromosomes leads to one being inactivated.
Determine the type of reproductive system and the number of Barr bodies for XXY chromosomes.
Male reproductive system with 1 Barr body per cell
Males typically have one X and one Y chromosome.
