4.4/4.5 - Genetic Disorders Flashcards
What is a karyotype?
A karyotype is the complete set of chromosomes in an organism.
What is non-disjunction?
The failure of homologous chromosomes to move to opposite poles of the cell during meiosis
This results in an abnormal number of chromosomes in the daughter cells, specifically gametes with 24 or 22 chromosomes in humans.
What are the consequences of non-disjunction?
One daughter cell has an extra chromosome while the other is missing a chromosome
These cells cannot function normally.
What is trisomy?
3 homologous chromosomes in place of a homologous pair
Occurs when a gamete with 24 chromosomes joins with a normal gamete (23).
What is monosomy?
Single chromosome in place of a homologous pair
Happens when a gamete with 22 chromosomes joins with a normal gamete.
What is Down syndrome?
An extra chromosome 21
Characteristics include a round, full face; short height; large forehead.
What is Turner Syndrome?
Turner syndrome is characterized by one X and no Y sex chromosome.
What are the characteristics of Turner syndrome?
Female in appearance, do not mature sexually, most miscarried before 20th week of pregnancy
What is Klinefelter syndrome?
2 X and one Y sex chromosome
Males are usually sterile and exhibit some feminine body characteristics.
What is prenatal testing?
Testing for a genetic disorder that occurs prior to birth
This includes methods such as amniocentesis.
What is amniocentesis?
A procedure using a long syringe and ultrasound to obtain cells from the fluid-filled sac surrounding the fetus
This is done when the fetus is large enough.
What are autosomes?
All chromosome pairs except for sex chromosomes
In humans, there are 22 pairs of autosomes.
What are sex cells?
Chromosome 23
They determine the sex of the offspring.
What is in vitro fertilization (IVF)?
Stimulation of ovaries using hormonal medications, retrieval of eggs, fertilization, and transferring the resulting embryo into the uterus
This is a type of assisted reproductive technology.
What is artificial insemination?
Putting sperm directly into the uterus
This method is used to facilitate conception.
What is maternal inheritance?
Type of inheritance where a zygote formed from two gametes inherits cytoplasmic DNA from only the female gamete (as female gametes have way more cytoplasm than male gametes do).
Paternal inheritance is this but only from male gamete
