Name _________________________________
Date ________________ Class ________
Review: Test 8 (Genetics and Meiosis)
1. What is a mutation? Change in the DNA sequence
2. If you get skin cancer from too much exposure to UV radiation, does this have an effect on
future offspring? Why or why not? No, because it does not affect your sex cells
3. Purebred (true-breeding)- Homozygous genotype (example: AA, aa, HH, ff, GG)
4. Hybrid- Heterozygous genotype (example: Aa, Ff, Gg)
5. Allele- Different forms of a trait (example: A-brown hair, a-blonde hair)
6. Recessive- Represented by lower case letter (example: h)
7. Heterozygous- Alleles are different (example: Aa, Ff, Gg)
8. Homozygous- Alleles are the same (example: AA, aa, HH, ff, GG)
9. Phenotype- Physical appearance (example: Brown hair, brown eyes, white fur, black fur)
10. Genotype- Written with letters (example: AA, Aa, aa, BB, Bb, bb)
11. Principle of dominance- Some traits are dominant over others. If brown hair (B) is dominant
over blonde hair (b) then, BB would have brown hair, Bb would also have brown hair, and bb
would have blonde hair.
12. In Cookie Monsters, blue fur (B) is dominant over orange (b). A male heterozygous blue cookie
monster marries a female with orange fur. What percentage of the offspring will be orange?
Male- Bb
Female- bb
Bb
bb
Bb
bb
Answer: 50% of the offspring will be orange (bb)
13. In Guinea pigs, short hair is due to a dominant gene and long hair is due to a recessive gene.
Cross a homozygous, short-haired guinea pig with a long-haired guinea pig. What percentage of
the offspring will have long hair?
Guinea pig 1- HH
Guinea pig 2- hh
Hh
Hh
Hh
Hh
Answer: 0% of the offspring will have
long hair (hh)
14. If the children (F1 generation) of the above cross mate with another heterozygous short-haired
guinea pig, what percentage of the offspring (F2 generation) will be short-haired?
Guinea pig 1- Hh
HH Hh
Guinea pig 2- Hh
Hh
hh
Answer: 75% of the offspring will have
short hair (HH or Hh)
15. In Dragons, blue skin color is dominant over red skin. If a homozygous blue dragon is crossed
with a red dragon, what percentage of the offspring will be blue?
Blue dragon- BB
Red dragon- bb
Bb
Bb
Bb
Bb
Answer: 100% of the offspring will
be blue (BB or Bb)
16. When a red flower that is homozygous for color (RR) is crossed with a yellow flower that is
homozygous for color (rr), all of the F1 generation offspring are red. What are the expected
genotypes and phenotypes of flower color in the F2 generation?
P generation
F1 generation
RR
Rr
<<<F2 generation
Red flower- RR
Red- Rr
Rr
rr
Genotypes: RR, Rr, rr
Yellow flower- rr
Phenotypes: Red and Yellow
17. Define and give an example of incomplete dominance. Alleles are not completely dominant
over each other. (example: Red flower crossed with White flower results in Pink flower)
18. Define and give an example of codominance. Phenotypes of both alleles are expressed.
(example: Red flower crossed with White flower results in Red/White patterned flower)
19. Cross PPtt x PpTt. What are the gamete combinations? Now, do the punnett square.
Gamete combinations: 1) Pt and 2)PT, Pt, pT, pt
20. Purple is dominant to white and tall is dominant to short. Do this dihybrid cross: PPTT x Pptt.
What are the genotypes and phenotypes of the offspring?
After completing punnett square, results should be….
50% PPTt
100% Purple and tall
50% PpTt
21. A pea plant with the genotype AaTt is crossed with a pea plant with the genotype aaTT. How
many different genotypes can be expressed in the offspring?
4 different genotypes:
AaTT
AaTt
aaTT
aaTt
22. Fill in this dihybrid cross and find the genotypic and phenotypic ratios and percentages:
Genotypic ratio:
1:2:1:2:4:2:1:2:1
Phenotypic ratio: 9:3:3:1
23. The diagram represents the chromosomes of a person with a genetic disorder caused by
nondisjunction, in which the chromosomes fail to separate properly. Which chromosome set
displays nondisjunction?
Answer: Chromosome set 18 displays nondisjunction
24. What is crossing-over? Draw an illustration of what happens to the chromosomes. Increases
genetic variation
25. Who was Gregor Mendel? The father of genetics
26. What did Gregor Mendel use to study the inheritance of traits? Pea plants
27. How are traits passed on? From your parents, through genes located in your DNA
28. What does the Punnett square show? Possible offspring
29. If you crossed purebred green plants with yellow plants, why would all the offspring be green?
Because the green plant is a purebred, all of the offspring would have a heterozygous genotype
resulting in a green phenotype (Gg)
30. How many times does the cell divide during meiosis? 2
31. How many chromosomes do the daughter cells have compared to the mother cells in meiosis?
Half as many (haploid cell). In humans, haploid cells contain 23 chromosomes
32. Does meiosis make sex cells or body cells? Sex cells (gametes)
33. How many cells are produced during meiosis? 4 genetically different haploid cells
34. Know how to read a pedigree chart.
35. Know the differences between point mutation, deletion, insertion and frameshift.