Chapter 19 Pt. 4

Question 1

What is crossing over?

Answer 1

corresponding pieces of chromatids of maternal and paternal homologues (nonsister chromatids) are exchanged during synapsis when the homologues are aligned side by side

Question 2

What happens after crossing over?

Answer 2

the affected chromatids have a mixture of DNA from the two parents

Question 3

________ _____ increases the genetic variability of gametes

Answer 3

crossing over

Question 4

crossing over increases the _______ ________ of gametes

Answer 4

genetic variability

Question 5

__________ ___________- a second way that meiosis provides for the shuffling of genes between generations

Answer 5

independent assortment

Question 6

In independent assortment, the relative positioning of homologous maternal and paternal chromosomes with respect to the poles of the cell is _______

Answer 6

random

Question 7

In ___________ __________, the relative positioning of homologous maternal and paternal chromosomes with respect to the poles of the cell is random

Answer 7

independent assortment

Question 8

During ___________ _________, the members of each homologous pair orient independently of the other pairs

Answer 8

independent assortment

Question 9

What is nondisjunction?

Answer 9

the failure of homologous chromosomes to separate during meiosis I or of sister chromatids to separate during meiosis II

Question 10

What is the difference between trisomy and monosomy?

Answer 10

trisomy- the condition in which there are 3 representatives of 1 chromosomes

monosomy- the condition in which there is only one representative of a particular chromosome in a cell

Question 11

Monosomy can be severe enough to cause the death of the _____, which will result in a _________

Answer 11

fetus

miscarriage

Question 12

What is a syndrome?

Answer 12

a group of symptoms that generally occur together

Question 13

What are the different types of syndromes?

Answer 13

Turner Syndrome 
Klinefelter Syndrome 
Triple-X Syndrome
Jacob Syndrome 
Down Syndrome

Question 14

Which syndrome is this: occurs in individuals who have only a single X chromosomes (XO)

Answer 14

Turner Syndrome

Question 15

Which syndrome is this: is observed in males who are XXY

Answer 15

Klinefelter Syndrome

Question 16

Which syndrome is this: a female with 3 X chromosomes

Answer 16

Triple-X Syndrome

Question 17

Which syndrome is this: a male with 2 Y chromosomes

Answer 17

Jacob Syndrome

Question 18

Which syndrome is this: born with 3 copies of chromosome 21

Answer 18

Down Syndrome

Question 19

What are the symptoms of Turner Syndrome?

Answer 19

• has the external appearance of a female
• may have thick fold of skin on the neck
• noticeably short
• chest is wide and underdeveloped breast
• ovaries are poorly developed, leading to infertility

Question 20

an extra X chromosome is twice as likely to come from the ____

Answer 20

egg

Question 21

True or False: Klinefelter Syndrome is very rare

Answer 21

False; Klinefelter Syndrome is fairly common

Question 22

What are the symptoms of XXY males (Klinefelter Syndrome)?

Answer 22

• testes remain small and don’t produce an adequate amount of the male sex hormone (testerone)
• taller than average (but less muscular)
• breasts may slightly develop
• testes may not produce sperm, which leads to sterile

Question 23

What are the symptoms of Triple-X Syndrome?

Answer 23

• have abnormal sexual development and are able to conceive children
• some have learning disabilities and delayed language skills

Question 24

What are the symptoms of Jacob Syndrome?

Answer 24

• produced when the chromatids of a replicated Y chromosomes fail to separate
• often taller than normal, and some have slightly lower than normal intelligence

Question 25

Down Syndrome is also known as _______ ___.

Answer 25

trisomy 21

Question 26

What are the symptoms of Down Syndrome?

Answer 26

• moderate to severe mental impairment
• short stature or shortened body parts (due to poor skeletal growth)
• typically have flattened nose
• a forward-protruding tongue that forces the mouth open
• upward-slanting eyes
• a fold of skin at the inner corner of each eye

Question 27

True or False: the risk of having a baby with Down Syndrome increases with the mother’s age

Answer 27

True