7.5 Study Guide Flashcards
Please give a definition for the word non-disjunction.
Chromosomes don’t separate properly during meiosis.
What happens during X-chromosome inactivation?
The gene on one x silences all other x chromosomes in the cell. Condenses into Barr body. Equalizes the amount of proteins produced from chromosome genes in males and females.
What are autosomes?
The chromosomes 1-22, all chromosomes except for sex chromosomes.
What determines whether a human’s biological sex at birth will be male or female?
The SRY gene.
How many of each chromosome type should a normal gamete have? A normal zygote?
1, 2.
Why are humans more tolerant of extra sex chromosomes than autosomes?
Because of the process of x-chromosome inactivation.
What is the term for this definition: Chromosomes don’t separate properly during meiosis?
Non-disjunction.
What happens with a deletion?
A gene is missing, so there’s only 1 instead of 2.
What happens with a duplication?
There are are extra gene(s), so there are 3 instead of 2.
What happens with an inversion?
They switch around. For example, ABCDEFGH will become ADCBEFGH. There might be more trouble pairing chromosomes for meiosis.
What happens with a translocation?
What are the sex chromosomes?
X and Y.
