Lesson 4 - Errors During Meiosis

Question 1

Non-Disjunction

Answer 1

Question 2

What is Trisomy

Answer 2

The addition of an extra chromosome (3 copies of 1 chromosome)

Zygote (fertilized egg) will have 47 chromosomes instead of 46

Question 3

What is Monosomy

Answer 3

The loss of a chromosome (1 copy of 1 chromosome)

The zygote (fertilized egg) will have 45 chromosomes instead of 46

Question 4

Diagnosing Non-Disjunction

Answer 4

Karyotype
- Displays chromosomes in a single cell by number and size
- White blood cells are extracted
- Add a solution that stimulates mitosis
- Add a solution that stops metaphase
- The photo is taken when the chromosome is
most condensed and then sorted

Prenatal Testing
- Testing for a genetic disorder that occurs before birth, involving a blood test
- Recommend for pregnant women over the age of 35 or based on family history

Amniocentesis
- Amniotic fluid, the fluid surrounding the fetus, is extracted

Chorionic Villus Sampling
- Cells from the chorion, a part of the placenta, are extracted

Multiple Marker Screening
- Tests for hormone levels associated with certain medical conditions