Sex Determination and Sex Chromosomes Flashcards
Cells of males have a tiny Y chromosome and a much larger X chromosome (True or False)
True
X and Y chromosomes share a lot of genes (True or False)
False
How many activated X-chromosomes do females have?
1
What is a barr body?
A Barr body or X-chromatin is an inactive X chromosome in a cell with more than one X chromosome
Why is the formation of the barr body significant
ensures that cells of both males & females have the same number of active X chromosomes to synthesize equivalent amounts of the products encoded by X-linked genes
The Lyon Hypothesis states that heterochromatization occurs in the early ages of childhood (True or False)
False (Answer: occurs in early embryonic development)
The Lyon Hypothesis states that heterochromatization is a random process (True or False)
True
X-Chromosome mosaicism occurs because?
Maternally and paternally derived X-chromosomes may contain different alleles for the same trait
Region of the mammalian X chromosome that is the major control unit and is located on the proximal end of the p arm in humans
X- inactivation center (Xic)
known to be a critical gene for X-inactivation
X-inactive specific transcript (XIST),
Are embryos hermaphrotic at one point (True or False)
True
can form either ovaries or testes, hence commonly referred to as bipotential gonads
Gonadal ridges
the gonadal ridges are made of what?
an outer cortex and inner medulla
The inner medulla from the gonadal ridge develops into the ovary (True or False)
False (Answer: it develops into the testis)
Among the Medulla and Cortex what develops into the ovary
cortex
