Mendelian Genetics and Punnet Squares
Section I – Vocabulary
Below is a list of all of the biology vocabulary terms used in the Unit. By the end of
the Unit, you will be able to write a working definition of each term and correctly
use each term.
allele
cross pollination
dominant
F1
F2
gene
genetics
genotype

heredity

heterozygous

homozygous

hybrid

Law of Independent Assortment

Law of Segregation

phenotype
probability
Punnett Square
Pure breed
recessive
self-pollination
test cross
trait
Section 2 – Mastery Objectives / Critical Thinking Skills
1.
2.
3.
4.
5.
6.
Distinguish between the concepts of phenotype and genotype
Summarize Mendel’s contribution to the science of genetics
Explain the laws of independent assortment and segregation as they apply to genetic
crosses.
Explain the idea of recessive and dominant traits
Predict the progeny of crosses for simple Mendelian traits using Punnett squares
Predict the frequency of phenotypes and genotypes through 2 generations
Section 3A –Required Readings

Miller and Levine – pp 262-274
Section 3B –Relevant Websites
Refer to the class wiki (http://nnhsbiology.pbworks.com
Section 4 –– Outside Class Assignments
Thoughtfully do each of the following assignments. Include all your reasoning and
work wherever it seems appropriate due dates for each assignment will be given in
class. (Please remember - homework that is passed in late is automatically
discounted 15%.)
1) Build a concept map with the following terms: dominant, recessive, phenotype,
genotype, heterozygous, homozygous, purebred, hybrid, trait and gene.
2) Mendel has been called the “Father of Genetics”. He is credited with
formulated two laws, 1. The Law of Independent Assortment and 2. the Law of
Segregation.
a) State the Law of Independent Assortment
b) State the Law of Segregation
c) Fill in the attached compare and contrast graphic organizer showing what
the two laws have in common how they are different.
3) Assume that right-handedness is dominant to left-handedness and brown eye
color is dominant to non-brown eye color. A brown eyed, right-handed man
marries a blue eyed-right handed woman. Their first child is left-handed and
has blue eyes.
a) What are the genotypes of the parents?
b) If they have more children, what might their genotypes and phenotypes be?
4) A wild population contains red-eyed and white-eyed flies. A scientist crosses
two white-eyed flies and gets all white eyed progeny (cross 1). She crosses two
red eyed flies and gets all red-eyed progeny (cross 2). When she crosses a
different pair of red-eyed flies, she gets 22 white eyed progeny and 78 redeyed progeny (cross 3). Explain her observations, giving the most probable
genotypes of the parents and progeny of each cross.
5) Your younger sister and her best friend have a get rich quick scheme. They are
planning to make money this summer by breeding guinea pigs to sell to
Newtonville Pet Store. Newtonville Pet will pay $12.00 for each black, smooth
coated guinea pig, $5.00 dollars for each white, rough coated guinea pig and
$2.00 for each white, smooth coated guinea pig. You already have a white rough
coated guinea pig that your sister is thinking about asking to “borrow” for the
task. Knowing that you have already studied genetics, they ask your advice.
(FYI: black coat color and smooth fur are recessive traits in guinea pigs.)
a) Should they breed the guinea pig you already have with another guinea pig?
b) If yes, what would be the best choice for a second guinea pig to breed it
with?
c) If they can’t use your guinea pig or decide not to, what choices would you
suggest for their breeding pair to maximize their profits?