Download Worksheet: Human Genetic Disorders

WS 7-3: Human Genetic Disorders
Name_________Key____________________________________
On the line provided, write the letter of the term from the list that matches each description.
Some can be used once, more than once, or not at all.
___C____1. disorder that causes a rapid breakdown of the
nervous system beginning at age 2 or 3
a. albinism
b. cystic fibrosis
___F___2. process that takes place when a c'some pair
fail to separate correctly during meiosis
___H___3. form of trisomy in which there is an extra copy
of c'some 21
c. Tay-Sachs disease
d. phenylketonuria
e. Huntington disease
___A___4. disorder that results in lack of pigment in hair
or skin
___B___5. disorder caused by a recessive allele on c'some 7
that results in fluid buildup in the lungs
f. nondisjunction
g. trisomy
h. Down syndrome
___G___6. Condition that exists when an individual is born
with cells that contain 3 copies of a c'some
___D___7. genetic disorder known as PKU, for which
newborn infants in PA are tested
i. neurofibromatosis
j. fragile-X syndrome
k. deletion
___K___8. process that occurs during meiosis when
pieces of c'somes break off and are lost
___E___9. disorder for which symptoms typically don't
appear until late 30s or 40s
___C___10. nervous system disorder that is most prevalent
in Jewish and French Canadian populations
___D___11. metabolic disease that if untreated can damage
the nervous system
___I___12. disease in which a skin spots may develop
into tumors
___J___13. disease that occurs mostly in males; when part
of the X c'come may be deleted
Directions: Place a check next to each accurate statement.
___√___14. The majority of genetic disorders are carried on the autosomes.
___√___15. Individuals with albinism are unable to produce the pigment responsible for most human
skin color.
_______16. cystic fibrosis is one of the least common fatal genetic disorders. It is the most
common.
_______17. Tay-Sachs disease is most common in families of South America. It is most common in
Jewish and French Canadian families.
___√___18. Sickle cell anemia is a blood disorder characterized by crescent shaped red blood cells.
_______19. In the US, sickle cell anemia is most common among people whose families come from
Europe. Should be Africa.
___√___20. PKU can cause severe mental retardation.
___√___21. Huntington is a rare dominant genetic disorder
_______22. 1 in 100 births are affected by nondisjunction About 1 in 1000
_______23. Turner syndrome affects only males. Someone with Turner is female.
_______24. Men with Klinefelter's syndrome have an extra Y c'some. Extra X.
___√___25. Down syndrome can result in circulatory problems.
Directions: Answer the following questions in the space provided.
26. What is a karyotype? Why would someone complete one? How are the c'somes arranged?
A picture in which the chromosomes have been paired and arranged in order from largest to
smallest. You would do it to check for a chromosome abnormality (such as wrong number,
deletion, or translocation).
27. Why do you think that people with Turner and Kleinfelter's syndrome are unable to reproduce?
(hint: analyze what they have for the sex c'somes) Because these individuals have abnormal
numbers of sex chromosomes, you might expect that there would be problems in proper
formation of their gametes. (In addition, their reproductive organs do not form properly.)
28. What is the difference between a autosomal genetic disorder and a sex-linked disorder? Which
one is more common and why? Autosomal is due to a gene on an autosome (any chromosome
except a sex chromosome). It is more common, since most of the chromosomes are
autosomes. It does not affect males and females differently. Sex-linked is due to a gene on
the X chromosome. If it is recessive, it will affect more males than females, since males have
only one X-chromosome. Males will pass the gene only to daughters.