1. Which trait is controlled by a gene with multiple alleles?
a. Blood type
b. Straight hairline
c. Smile dimples
d. widow’s peak

2. A. Blood type

3. What are multiple alleles?
a. More than 2 genes for a trait
b. Three or more chromosomes that determine a trait
c. 2 codominant genes
d. 3 or more forms of a gene that code for a single trait

4. D. 3 or more forms
of a gene that code
for a single trait

5. Why does height in humans have such a wide variety of phenotypes?
A. Controlled by a recessive allele
b. Has only 2 alleles
c. Controlled by sex-linked genes
d. Controlled by at least 4 genes

6. D. Controlled by at least 4 genes

7. What controls variations in skin color among humans?
a. Multiple alleles
b. A person’s diet
c. Two alleles of a single gene
d. At least 3 genes

8. D. At least 3 genes

9. What human trait is altered by variations in the environment?
Smile dimples
Blood type
c. Height
d. Skin color

10. c. Height

11. What is a pedigree?
A. Chart tracking family members that have a certain trait
b. Picture of chromosomes
c. Geneticist studying traits
d. Allele passed from parent to offspring

12. A. Chart tracking family members that have a certain trait

13. Genetic disorders are caused by
a. Dominant alleles
b. Pedigrees
c. sickle-shaped cells
d. mutations

14. d. mutations

15. Down Syndrome occurs when
A. A person inherits a recessive allele
b. Sickle-shaped cells get stuck in blood vessels
c.chromosomes fail to separate properly
d. blood does not clot properly

16. c.chromosomes fail to separate properly

17. Why are sex-linked traits more common in males than females?
a.All alleles on the X are dominant
b. All alleles on the Y are recessive
c. A recessive on the X produces the trait in a male
d. The X and Y are codominant

18. c. A recessive on the X produces the trait in a male

19. What is a karyotype?
A.blood from a new born baby
b. Fluid surrounding an unborn baby
c. Picture of chromosomes in a cell
d. Picture of a baby before it is born

20. c. Picture of chromosomes in a cell

21. Cloning results in organisms that are
a. Genetically similar
b. Produced from cuttings
c. Both adult mammals
d. Genetically identical

22. d. Genetically identical

23. No two people have the same DNA except for
Brothers
Sisters
Identical twins
d. Crime suspects

24. c. Identical twins

25. Which form of selective breeding crosses genetically different individuals in an attempt to keep the best traits of both parents?
Hybridization
inbreeding
Cloning
Genetic engineering

26. Hybridization

27. What is a genome?
All the plasmids from splicing DNA in a cell
All the DNA in one cell of an organism
All the karyotypes in a cell
All the cells produced during meiosis

28. b.All the DNA in one cell of an organism