Lecture 18- Human Genetics

Question 1

What is nondisjunction?

Answer 1

The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during cell division

Question 2

A human diploid cell with 47 chromosomes would be considered ____________.

Answer 2

Trisomic

Question 3

What are the four types of changes to chromosome structure discussed in lecture?

Answer 3

Deletion, duplication, inversion, & translocation

Question 4

What does it mean for a disorder to be autosomal recessive?

Answer 4

Two copies of an abnormal recessive gene must be present in order for the disorder to develop (gg)

Question 5

During which stage(s) of meiosis could nondisjunction occur?

Answer 5

Anaphase I and/or Anaphase II

Question 6

True or false: Sickle cell anemia is caused by the substitution of a single amino acid in hemoglobin

Answer 6

True

Question 7

Which term is used to describe a human diploid cell that is missing a single chromosome?

Answer 7

Monosomy

Question 8

What is an example of an autosomal dominant disorder discussed in lecture?

Answer 8

Polydactyly

Question 9

An individual with the appropriate number of chromosomes for their species is called a(n)

Answer 9

Euploid (disomy)

Question 10

How is malaria related to sickle cell anemia?

Answer 10

Malaria effects normal red blood cells (erythrocytes) more than heterozygous for sickle cell anemia. Therefore homozygotes for sickle cell anemia are at a disadvantage for malaria survival

Question 11

What is Huntington’s disease?

Answer 11

Autosomal dominant neurodegenerative disease

Question 12

What is aneuploidy?

Answer 12

The presence of an abnormal number of chromosomes in a cell

Question 13

What is Turner syndrome?

Answer 13

Genetic condition in which a female is partly or completely missing an X chromosome

Question 14

What is genomic imprinting?

Answer 14

Process by which genes are permanently methylated during gamete formation

Question 15

A(n) ___________ is the detachment, rotation, and reinsertion of a segment of a chromosome

Answer 15

Chromosome inversion

Question 16

True or false: A carrier for sickle cell anemia would not exhibit the sickle cell allele in their phenotype

Answer 16

False; sickle cell anemia carriers are codina by (both alleles are expressed/both types of hemoglobin/erythrocytes

Question 17

What is chromosomal translocation?

Answer 17

Phenomenon in which two detached fragments of two different chromosomes are switched

Question 18

Which disorder would a male individual have if they inherited an extra X chromosome?

Answer 18

Klinefelter syndrome (XXY)

Question 19

True or false: a heterozygote for an autosomal recessive disorder would partially exhibit the phenotype

Answer 19

False; a heterozygote for an autosomal recessive disorder is considered a carrier

Question 20

A trisomy mutation of chromosome 21 in humans would lead to which disorder?

Answer 20

Down syndrome

Question 21

True or false: Sickle cell anemia is an autosomal dominant disorder

Answer 21

False; sickle cell anemia is an autosomal recessive disorder

Question 22

What is amniocentesis?

Answer 22

Procedure in which amniotic fluid (with live fetal cells/ proteins) is removed from the uterus for testing (14-16 weeks gestation)

Question 23

In which stage of meiosis would chromosomal translocation be most likely to occur?

Answer 23

Prophase I

Question 24

What is chorionic villus biopsy?

Answer 24

Prenatal test in which a sample of the chorionic villi is scraped from the placenta for genetic testing (10-12 weeks gestation)

Question 25

What is phenylketonuria? (PKU)

Answer 25

Autosomal recessive disorder in which dietary phenylalanine cannot be metabolized

Question 26

Which disorders in humans are a result of genomic imprinting?

Answer 26

Angelman & Prader-Willi syndromes