At the end of the lesson, students are expected to:
a. use a Punnett Square to solve monohybrid crosses;
b. employ the steps for solving monohybrid cross using the Punnett Square; and c. determine the genotypes and phenotypes of the offspring; II. Subject Matter:
a. Topic: Monohybrid Cross Using a Punnett Square
* Exploring Life through Science – Biology
By: John Donnie Ramos, et. Al. pp. 381-397
* Science and Technology – Biology
By: Maria Olivares, et. Al. pp. 190-223
By: NPSBE pp.165-177
* Power Point Presentation
* Figures of Cartoon Characters
* Punnett Square Board
* Value the importance of Punnett Square in Predicting genetic outcomes of a monohybrid cross
Teacher’s Activity Students’ Activity
c.Checking of Attendance
What have we discussed
Determining homozygous and heterozygous traits, dominant and recessive traits and genotype and phenotype
That’s right! When do we
say that a trait is homozygous?
If the alleles both carry the same trait, they are homozygous,
Very good! How about the
If the alleles carry opposite traits they are heterozygous.
Brilliant! How about
dominant and recessive
Dominant traits are the observable traits of an individual while the recessive traits are the ones that are hidden
Excellent! What about
Genotypes are the factors that cause the phenotype which are the observable traits.
Precisely! Do you have
Genetics with a Smile
Part A: Smiley Face Traits
(1) Obtain two coins from your
teacher. Mark one coin with a
“F” and the other with a “M” to
represent each of the parents.
The parents are heterozygous
for all the Smiley Face traits.
(2) Flip the coins for parent for each
trait. If the coin lands with heads
up, it represents a dominant allele.
A coin that lands tails up indicates
a recessive allele. Record the
result for each person by circling
the correct letter. Use the results
and the Smiley Face Traits page to
determine the genotype and
phenotype for each trait.
Part B: Is it a boy or girl?
To determine the sex of your
smiley face, flip the coin for the male
parent. Heads would represent X,
while tailswould be Y.
Part C: Create Your Smiley Face!
Use the Smiley Face Traits chart
and your results from Part A to create
your smiley face in a sheet of a bond
a. Presentation of the Lesson
In relation to the chances in tossing
coins, genetics can also predict outcomes
in a monohybrid cross using a Punnett
b. Lesson Proper
What is Monohybrid cross?
Monohybrid cross is a method of determiningthe inheritance pattern of a trait between two single organisms.
Very Good! In order to present the
crossing clearly, a visual representation
of a diagram is used.
What do we call this diagram,
Punnett Square, ma’am
Good! What is a Punnett Square?
Punnett Square is a chart which shows or predictall possible gene combination in a cross of parents
Great! Who devised the diagram?
Reginald C. Punnett, ma’am
Good! Let us take this one as
In pea plants, tall pea plants are
dominant over the short pea plants.
Using Punnett Squares let us predict the
phenotypes and genotypes of the offsfring...