Download Heridity: Passing It On

ANSWER KEY -- Heredity: Passing It On OMM pg. 230
1. What is mitosis?
Mitosis is the process in which a nucleus divides and two
genetically identical nuclei result.
2. What is meiosis?
A reproductive process in which the nucleus of the parent
cell divides twice thus resulting in the formation of sex
cells (gametes) that contain exactly half of the
chromosomes than the other cells in your body.
3. Why is the difference between mitosis and meiosis significant (important)?
Mitosis is significant because when a cell undergoes this process, the result is an
exact copy of the parent cell (the 46 individual chromosome make exact copies of
themselves). This is great when our bodies need to replace dying or dead cells such as bone & skin
cells.
Meiosis is similar but the results are different. Our sex cells result from this process which result in
these cells containing 23 individual chromosomes. This is significant because when the egg and sperm
unite, the offspring contains the combination of the chromosomes and results in an unique individual.
4. Body cells have 46 individual chromosomes and sex cells have only 23 individual chromosomes
- Why? Sex cells only have 23 chromosomes because when to unite together they give the offspring
the required amount of 46 total individual chromosomes.
5. How do we represent (write):

Dominant genes? With a capital letter

Recessive genes? With a lowercase letter

Purebred (homozygous) genes? With two of the same alleles (ex. Tt, TT)

Hybrid (heterozygous) genes? With two different alleles (ex. Tt)
6. In the land of Umgarn, the people have blue skin or green skin. B (blue) is the dominant
(stronger) gene and b (green) is the recessive (hidden) gene.
a. What are the possible genotypes:
Homozygous
BB, bb
Heterozygous
Bb, bB
b. What are the phenotypes for each genotype:
Genotype
BB
bb
Bb
bB
Phenotype
blue
green
blue
blue