karytotype performance assessment
What is a karyotype?
A karyotype is an organized profile of a person's chromosomes. Two chromosomes specify the gender, and the rest are arranged in homologous pairs from largest to smallest.
Describe differences in a normal karyotype and abnormal karyotypes.
A normal karyotype contains 23 homologous pairs of chromosomes, 2 chromosomes in each set. An abnormal karyotype will have an incorrect distribution of chromosomes, with one cell getting two copies of a chromosome and another cell receiving none (this is known as nondisjunction).
What is the difference between an autosomal and sex chromosome?
Autosomal chromosomes are the non sex chromosomes that give a person their hair color, eye color, etc. and a sex chromosome specify the gender of a person (either XX for female or XY for male).
How can doctors use karyotypes to help diagnose different disorders?
Doctors are able to look at the person's chromosomes to identify if someone is either missing or has an extra chromosome, then allowing the doctor to diagnose genetic disorders.
Compare and contrast the process and ending results of mitosis and meiosis.
Mitosis: Zygote copies each of its chromosomes before it divides to make two cells (copies are the sister chromatids) The zygote gives each cell on identical copy of each chromosome Start with 46 diploid chromosomes, ends with 46 diploid chromosomes Goes through PMAT and cytokinesis once Meiosis: Purpose is to reduce the number of chromosomes by half for reproduction and to create genetic diversity Cell copies each chromosomes, then the homologous pairs line up and exchange pieces (recombination) The homologous chromosomes are divided into two daughter cells, and the sister chromatids are pulled apart into a total of four cells Each of the 4 new gamete cells have one copy of 23 chromosomes with a unique combination of maternal/paternal genes Starts with 46 diploid chromosomes, ends with 4 gamete cells, each with 23 haploid chromosomes Goes through PMAT and cytokinesis twice Meiosis 1 purpose: separate the tetrads and make the cells haploid Meiosis 2 purpose: separate the sister chromatids to ensure that each new cell has only one copy
How is monosomy different than trisomy?
Monosomy is when a zygote is missing a chromosome and trisomy is when the zygote has three copies of a chromosome. Autosomal trisomy and monosomy are lethal to the zygote because the baby could have too little/ too much genetic information. If the baby is born with the extra/missing chromosomes (most commonly one of the smaller chromosomes), then the baby will have a genetic disorder.
What is nondisjunction? What would be the consequences if nondisjunction occurs in cells during meiosis? In mitosis?
Nondisjunction is when there is an incorrect distribution of chromosomes, where one cell may receive two copies of a chromosome and another cell may receive none. If the cells created in meiosis have either too many or not enough chromosomes, this will produce a zygote with too many/not enough chromosomes, affecting the genes of the offspring.
