13.3

Question 1

Explain how mutations can cause disease.

Answer 1

Mutations in DNA cause a different amino acid to be inserted which can change protein function

Question 2

Describe the consequences when nondisjunction changes
chromosome number

Answer 2

o Failure of homologues or sister chromatids to separate properly during meiosis
 Aneuploidy
* Gain or loss of a chromosome
* In all but a few cases, do not survive
* Monosomy
o Loss
* Trisomy
o Gain

Question 3

Describe the consequences of nondisjunction of autosomes

Answer 3

o Small autosomes can present as 3 copies and allow individual to survive
 Example
* Down syndrome
o Trisomy 21
 Usually fatal except for Trisomy 21 or 22

Question 4

Describe the consequences of nondisjunction of sex chromosomes

Answer 4

 Don’t generally experience severe developmental abnormalities
* Nonviable result is the only fatal one
o Can lead to a miscarriage

Question 5

Recognize how genomic imprinting can lead to non-Mendelian inheritance.

Answer 5

o Phenotype exhibited by a particular allele depends on which parent contribute the allele to the offspring
o Only the paternal OR the maternal allele is expressed

Question 6

Describe how epigenetics can lead to changes in gene function

Answer 6

Changes in gene function WITHOUT causing a change in DNA sequence

Question 7

amniocentesis for fetal genetic testing

Answer 7

 Collects fetal cells from the amniotic fluid for examination
* With a needle through the belly

Question 8

chronic villi sampling for fetal genetic testing

Answer 8

 Collects cells from the placenta for examination
* With a long needle like thing through the vaginal canal