Question
Down's Syndrome is also called Trisomy 21 because affected people have three copies of chromosome 21. How is this possible?
a
In a mistake in meiosis, the fertilized egg has two copies of chromosome 21.
b
Either the sperm cell or the egg cell has one copy of chromosome 21.
c
In a mistake in mitosis, the fertilized egg has two copies of chromosome 21.
d
Either the sperm cell or the egg cell has two copies of chromosome 21.
a
In a mistake in meiosis, the fertilized egg has two copies of chromosome 21.
b
Either the sperm cell or the egg cell has one copy of chromosome 21.
c
In a mistake in mitosis, the fertilized egg has two copies of chromosome 21.
d
Either the sperm cell or the egg cell has two copies of chromosome 21.
Answers
GPT-4o mini
The correct answer is:
**d - Either the sperm cell or the egg cell has two copies of chromosome 21.**
This occurs due to a mistake in meiosis, where the process of gamete formation results in one of the gametes (sperm or egg) having an extra copy of chromosome 21. When this gamete fuses with a normal gamete, the resulting fertilized egg has three copies of chromosome 21, which leads to Down's Syndrome, also known as Trisomy 21.
**d - Either the sperm cell or the egg cell has two copies of chromosome 21.**
This occurs due to a mistake in meiosis, where the process of gamete formation results in one of the gametes (sperm or egg) having an extra copy of chromosome 21. When this gamete fuses with a normal gamete, the resulting fertilized egg has three copies of chromosome 21, which leads to Down's Syndrome, also known as Trisomy 21.