Chapter 15

Question 1

Chromosome theory of inheritance

Answer 1

Mendelian genes have specific loci along chromosomes.

Question 2

Wild type

Answer 2

Most common genotype in nature, doesn’t mean it’s recessive or dominant.

Question 3

Linked genes

Answer 3

Genes located near/on the same chromosome TEND to be inherited together.

Question 4

Sex-linked

Answer 4

On either sex chromosome. Men are not usually carriers (X Y).

Question 5

Recombinants

Answer 5

New combination of genes compared to parent genes.

Question 6

Genetic recombination

Answer 6

Due to crossing over of genes. Offspring with combinations that differ.

Question 7

Sex gender determination systems

Answer 7

1. XX-XY: Mammals
2. XX-X__: some insects, crickets, grasshoppers
3. ZW-ZZ: Common in birds, some fish, and some insects
4. Haplo-Diploid: Most bees and ants.

Sex chromosomes do NOT always determine the sex.

Question 8

Haplo-Diploid

Answer 8

Develop from unfertilized eggs. Most bees and ants.

Question 9

ZW-ZZ

Answer 9

ZW = female, ZZ = Male. Common in birds, some fish, and some insects.

Question 10

XX-X__

Answer 10

XX - Female, X(O) - Male. Some insects.

Question 11

X-inactivation

Answer 11

Heterozygous for sex linked trait = half cells one allele, other half another allele.

Question 12

Nondisjunction

Answer 12

Members of a pair don’t move apart properly during meiosis I or II. Leads to aneuploidy. Disjunction: what normally happens.

Question 13

Aneuploidy

Answer 13

Abnormal # of a particular chromosome.

Question 14

Trisomic

Answer 14

Additional Chromosome. 2n + 1.

Question 15

Monosomic

Answer 15

Missing 1 chromosome. 2n - 1.

Question 16

Polyploidy

Answer 16

Having an unusual number of chromosome sets. 2n -> 3n or 4n, etc.
-Can be caused by the failure of a zygote to divide, leaving it a 2n. Then during mitosis, it becomes a 4n.
-Common in plants
-Rare in animals.

Question 17

Alterations in Chromosome structure

Answer 17

1. Deletions: Chromosomal fragment is lost
2. Duplication: Broken fragment may become reattached as an extra segment to a sister or non-sister chromatid.
3. Inversions: Flipped code.
4. Translocation: change places.

Question 18

Klinefelter’s Syndrome

Answer 18

XXY. Where men are born with an extra X chromosome.
Klinefelter syndrome may increase the risk of:
-Anxiety and depression.
-Social, emotional and behavioral problems, such as low self-esteem, emotional immaturity and impulsiveness.
-Infertility and problems with sexual function.
-Weak bones (osteoporosis)
-Heart and blood vessel disease.
-Breast cancer and certain other cancers

Question 19

XYY

Answer 19

Supermale, does not equal more testosterone.

About 1 in 1,000 boys have it. Boys with XYY syndrome — also known as 47,XYY — might be taller than other boys. Other symptoms can include problems with spoken language and processing spoken words, coordination problems, weaker muscles, hand tremors, and behavioral problems.

Question 20

Trisomy X

Answer 20

An extra X chromosome in women. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features.

Question 21

Turner’s Syndrome

Answer 21

Turner syndrome, a condition that affects only females, results when one of the X chromosomes (sex chromosomes) is missing or partially missing. Turner syndrome can cause a variety of medical and developmental problems, including short height, failure of the ovaries to develop and heart defects.

Question 22

Trisomy 18

Answer 22

Edward’s Syndrome. Developement problems.

Question 23

Trisomy 21

Answer 23

Down Syndrome

Question 24

Trisomy 13

Answer 24

Patau’s syndrome