IAC White Set Science Bee Practice Test

Lyonization can convert one form of these structures into a Barr body.

X chromosome Y chromosome Autosomes Mitochondria

Correct Answer:

X chromosome

Explanation:

Lyonization is X-chromosome inactivation in female mammals. To balance gene expression between males (one X) and females (two Xs), one X chromosome in each cell is largely silenced. The silenced X condenses into a dense, inactive form called a Barr body, typically located near the nuclear envelope. This targeted silencing happens specifically to the X chromosome, not to the Y chromosome, autosomes, or mitochondria, which don’t form Barr bodies. So lyonization converts an X chromosome into a Barr body, explaining the mosaic pattern of X-linked gene expression in females.

Access more questions from this quiz

Continue to IAC White Set Science Bee Practice Test for more practice questions and the full quiz experience.

Access More Questions