Question

In which of the following is an extra pair of chromosomes found?

• A. Trisomic
• B. Double trisomic
• C. Tetrasomic
• D. Nullisomic

Hint:

Trisomy is characterized by an extra chromosome, while tetrasomy involves two extra pairs of chromosomes.

Answer 1

The Correct Option is A

Step 1: Understand chromosomal abnormalities.
- Trisomy occurs when there is one extra chromosome, making the total number of chromosomes 47 instead of the normal 46 (e.g., Down syndrome with an extra chromosome 21). - Double trisomy involves two extra chromosomes. - Tetrasomy refers to the presence of an extra pair of chromosomes (four copies of a chromosome). - Nullisomy occurs when there is a loss of both chromosomes from a pair.
Step 2: Review the options.
- Trisomic refers to the condition where an organism has one extra chromosome. This is a known chromosomal abnormality. - Double trisomic refers to having two extra chromosomes, not just one. - Tetrasomic refers to having four copies of a chromosome. - Nullisomic refers to the absence of both chromosomes from a pair.
Step 3: Conclude.
The correct term for having an extra pair of chromosomes is trisomic, so option (A) is the correct answer.
Final Answer: \[ \boxed{\text{Trisomic}} \]