Genetics Review WS
Vocabulary Review:
Use the review puzzle to help you fill in the blanks with the correct vocabulary terms, you may also reference
your notes in your science notebook to fill these in.
In the field of genetics scientists focus on the study of 1. ___________________, which is how genes
are passed on from parents to offspring. The sequences of DNA that code for the different chemical factors,
or proteins, are known as 2. ___________________. Different forms of a gene are known as
3.___________________. Some genes are 4.___________________ because they are always expressed or
shown. Other genes are known as 5. ___________________, because you need two copies of the recessive
gene for it to be expressed.
Brown hair, blonde hair, red hair, and brunette hair are different physical traits, or
6.___________________ that people can have. The physical traits of an organism will always be determined
by their 7.___________________, or genetic make-up. When talking about alleles we often use letters to
represent the various genes. For example, if an organism has the following genotype AA, we say that they are
8.___________________ ___________________ for that trait. On the other hand the genotype Aa is known
as being 9.___________________ for that trait. Lastly, an organism with the genotype aa is known as being
10.___________________ ___________________ for that trait.
There are 2 different types of cells; the body or 11. ___________________ cells which are known as
being 12. ___________________ because they contain 2 sets of chromosomes. Then there are the sex cells or
13. ___________________, which are 14. ___________________ because they only have one set of
chromosomes. The sex cells are produced through the process of 15. ___________________, in which the
number of chromosomes are 16. ___________________.
Review Problems:
1. Label each of the following as homozygous dominant, heterozygous, or homozygous recessive:
AA _______________
Tt ________________
aa _________________
TT _________________
Aa __________________
tt ___________________
2. In pigs, having pointed ears is dominant (E) over having curved ears (e). A heterozygous female with
pointed ears mates with a male that has curved ears.
Female parent genotype _______
Male parent genotype
_______
% offspring with pointed ears
_______
% offspring with curved ears
_______
Genetics Review WS
3. Black wool of sheep is due to a recessive gene (b) and white wool to its dominant gene (B). A
heterozygous white buck (male) is crossed to a homozygous white ewe (female). Find the genotypes
and phenotypes of their offspring.
Female parent genotype _______
Male parent genotype
_______
% offspring with white wool
_______
% offspring with black wool
_______
4. The lack of pigmentation, called albinism, in humans is the result of a recessive gene (a). Two normal
parents have an albino child.
a) What are the genotypes of the parents?
b) What is the probability of the parents having another albino child?
5.
6. In fruit flies, eye is a sex-linked trait, where red-eyes (R) are dominant over white eyes (r). Show the
cross between a white-eyed female and a red-eyed male.
7. In humans hemophilia is a sex-linked recessive trait (h). What will be the results if a female carrier has
children with a male who has hemophilia?
8. In humans color blindness is a sex-linked recessive trait (c). What is the probability of the children
being color blind if a color blind female has children with a normal vision male?
9. On Mars there exist an animal called the Martian Rat. Its skin color can be blue (B) or red (R) if they are
homozygous. The heterozygous form of the trait results in red and blue spotted skin. Show the cross
between a blue female Martian Rat and a spotted male Martian rat.