Download SR 9-2 and Quiz #6

Collect SR 9-2 and Quiz #27

Announcement
– Test Day 1 next week on Ch. 8 and Ch. 9
– You will need a coin today.
1.
2.
In a species of bat, poison saliva (P) is
dominant over sticky saliva (p). If a bat that is
homozygous for poison saliva is crossed with a
bat that is homozygous for sticky saliva, what
are the possible genotypes and phenotypes of
the offspring? Show your work in a Punnett
Square.
A type of lizard can have either brown (B) or
green (b) skin, and either a large (L) or a small
(l) tail. You cross a brown, large-tailed lizard
(homozygous for both traits) with a green,
small-tailed lizard.
–
–
What are the possible genotypes of the offspring?
What are the possible phenotypes of the offspring?
Agenda
Collect HW
 Quiz
 Purpose of Punnett squares
 Codominance and incomplete dominance
 Make a baby activity
 Review for test

What is the purpose?

What is the point of Punnett squares?
– Give probability
Why is it helpful for a farmer to know
probability?
 A dog breeder?
 A couple?

What is the purpose?
What is the purpose of alleles? Why are some
dominant and others are recessive?
 Well, what are they made out of?
 Think about the central dogma.

– DNA  RNA  protein
If the gene does not code for a protein, will it be
made?
 Therefore, dominant alleles code for a protein
(brown hair) that recessive alleles can’t code for
(blonde hair)

But what if… #1
What if the dominant allele is not completely
dominant?
 What happens if the red allele does not produce
enough of the red protein?
 When the dominant gene is not completely
dominant, it is called incomplete dominance

– Produces a middle phenotype

RED Flower x WHITE Flower  PINK Flower
But what if… #2

What if both alleles are dominant?
– Which allele wins? Both!

When both alleles are dominant, this is
called codominance
– This can produce both phenotypes to show up

I remember codominance in the form of
an example like
– red x white ---> red & white spotted
Make a baby activity
You will be in partners
 You will make a baby
 I will explain so listen

Review for the test
Test will cover Ch 8 Mitosis and Ch 9
Meiosis and Probability
 Go over your old quizzes
 Go over homework and vocabulary

Guaranteed to be on the test

Words like
–
–
–
–
–
–
–
–

Diploid (2n)/haploid (n)
hetero/homozygous
Homologous chromosome
Dominant/recessive/codominance/incomplete
dominance
Genotype/phenotype
P and F generation
Traits, genes, alleles
Chromosome, chromatin, sister chromatid
Topics like
– Mendel’s 3 Laws
– Phases of mitosis/meiosis
– Punnett squares
Homework
Study for test
 Finish “baby” drawing with all labels
 Go over Chapter 8 and 9 Review
 Have a good day!
