Chromosome Errors (Variants)

Question 1

What to we call the failure of chromosomal separation?

Answer 1

Non-disjunction

Question 2

How many daughter gametes will have an abnormality if non-disjunction occurs in Anaphase 1?

Answer 2

All four daughter gametes (two with trisomy, two monosomy)

Question 3

How many daughter gametes will have an abnormality if non-disjunction occurs in Anaphase 2?

Answer 3

Two of the four daughter gametes (one trisomy, one monosomy)

Question 4

What causes chromosome errors?

Answer 4

An abnormality in chromosome amount or DNA sequences during crossing-over

Question 5

What is the difference between structural errors and point mutations?

Answer 5

Structural errors - impact whole gene sequences

Point mutations - impact one or two nitrogenous bases

Question 6

How many types of structural errors are there?

Answer 6

1. Deletion - a segment is deleted
2. Duplication - a segment is duplicated
3. Inversion - a segment is flipped
4. Translocation - segment is put on the wrong chromosome

Question 7

How many types of point mutations are there?

Answer 7

1. Base pair substitution - a base pair is copied wrong
2. Insertion - a new base is added
3. Deletion - a pre-existing base is removed

Question 8

Can we diagnose non-disjunction in the womb?

Answer 8

Yes

Question 9

How many ways can we diagnose non-disjunction prenatally?

Answer 9

1. Chorionic Villus Sampling
2. Amniocentesis
3. Multiple Marker Screening

Question 10

Need more review?

Answer 10

Pg. 166 # 1, 2, 9