Name: ___________________________________________ Period: _________
STAAR/EOC Biology: Category 2-Mechanisms of Genetics (1)
Part1: DNA
1. The monomer of DNA isa. Amino acid
b. nucleotide
c. lipid
d. monosaccharide
2. Circle the DNA monomer in the picture to the right 
3. The backbone of the DNA double helix is made up of
a. __________________________________
b. __________________________________
4. What type of sugar is present in DNA?
a. Ribose sugar
b. Deoxyribose sugar
5. What type of sugar is present in RNA?
a. Ribose sugar
b. Deoxyribose sugar
6. What is the difference between DNA and RNA?
a. DNA is single stranded, RNA is double stranded
b. DNA is double stranded, RNA is single stranded
7. A change in the DNA of an organism is called a ___________________________________.
8. When a nitrogen is ADDED to a DNA sequence that is called aa. Deletion
b. insertion
c. point
9. When a change in the DNA causes the DNA to be read incorrectly that is called aa. Codon mutation
b. point mutation
c. frame shift mutation
10. When someone spends a lot of time sunbathing and rarely puts on sunscreen, they will have an increased risk
of developing skin cancer becausea. Radiation and UV light can alter DNA
b. Skin dries out
c. High temperature will alter DNA in a positive way
11. A female with lung cancer is pregnant. She fears that she will pass the disease onto her baby. Should she be
worried?
a. No, because the cancer in her lungs and that does not affect her gametes
b. Yes, because cancer is in the DNA of her gamete from her lung cells
Part 2: Sexual Reproduction
12. What process creates gametes in the human body?
a. Mitosis
b. budding
c. meiosis
d. conjugation
13. Compared to mitosis that creates 2 genetically identical cells, meiosis creates __________ cells that are
genetically __________________________.
14. How many times does the cell divide in meiosis?
a. 1
b. 2
c. 3
d. 0
15. Define diploid: _____________________________________________________________________________
16. Define haploid: _____________________________________________________________________________
17. A dove has a diploid number of 16 chromosomes. How many chromosomes will be present in their gametes?
a. 16
b. 12
c. 8
d. 4
Part 3: Genetics
18. A genotype with 2 dominant alleles is calleda. Homozygous
b. heterozygous
19. A genotype with 1 dominant allele and 1 recessive allele is calleda. Homozygous
b. heterozygous
20. A genotype with 2 recessive alleles is calleda. Homozygous
b. heterozygous
21. In the punnett square to the right  (Gg x Gg)
a. What is the probability of having a homozygous dominant offspring? _________%
b. What is the probability of having a heterozygous offspring? _________ %
c. What is the probability of having a homozygous recessive offspring? _______ %
22. In mice, brown hair is dominant to white hair. Cross a heterozygous female with a homozygous dominant
male. The phenotype ratio will be:
a. 3 brown : 1 white
b. 4 brown: 0 white
c. 2 brown: 2 white
d. 1 brown: 3 white
23. In humans, free-ear lobes are dominant to attached.
Two parents that are both heterozygous free are expecting a child.
a. What are the chances that the child will have free ear
lobes?_____________%
b. What are the chances that the child will attached ear
lobes?_____________%
24. Define “Codominance”: _______________________________________________________________________
25. In some chickens, the gene for feather color is controlled by codominance. The allele for black is B and the
allele for white is W. The heterozygous phenotype is known as erminette.
a. What is the genotype for black chickens? _______
b. What is the genotype for white chickens? _______
c. What is the genotype for erminette chickens? ______
26. Define “Incomplete Dominance”: _______________________________________________________________
27. In snapdragons, flower color is controlled by incomplete dominance. The two alleles are red (R) and white
(W). The heterozygous genotype is expressed as pink.
a. What is the phenotype of a plant with the genotype RR? ___________
b. What is the phenotype of a plant with the genotype WW? ___________
c. What is the phenotype of a plant with the genotype RW? ___________