Punnett Squares

Multiple Choice

Heterozygous is when...

• the alleles are the same
• the alleles are different
• the alleles are absent
• the alleles are present

Multiple Choice

Homozygous is when...

• the alleles are the same
• the alleles are different
• the alleles are absent
• the alleles are present

Multiple Choice

What are different forms of a gene called?

• Alleles

• Chromosomes

• Factors

• Traits

Multiple Choice

This type of allele overpowers the recessive allele and is capital ________________

• Dominant
• Homozygous
• Genotype
• Phenotype

Multiple Choice

This type of allele "loses" and will not overpower ________________

• Dominant
• Homozygous
• Recessive

• Phenotype

Punnett Squares

Multiple Choice

What is a phenotype

• The genetic make up (code)
• The physical trait

Introduction to Punnett Squares

• Punnett squares are a visual tool used to predict the possible outcomes of a genetic cross (outcome of your parent's mixing their genes)

• They help determine the probability of inheriting specific traits.

• Each square represents a possible combination of alleles from the parents.

Multiple Select

What is the purpose of Punnett squares?

• To predict the possible outcomes of an offspring using their parent's genes.

• To determine the probability of inheriting specific traits

• To look at the DNA

Understanding Punnett Squares

• They show the genotypes and phenotypes of offspring based on the alleles inherited from each parent.

• Each parent's alleles are represented by letters, with dominant alleles shown in uppercase and recessive alleles in lowercase.

• The genotype represents the combination of alleles, while the phenotype represents the observable traits.

Basically...

• Punnett squares let you figure out which traits will be passed down to the offspring.

• If mom has blue eyes, and dad has brown eyes, making Punnett squares lets you figure out the probability for what color eyes the child has.

​Let's Practice

Multiple Choice

What percentage will be a yellow?

• 25%

• 50%

• 75 %

• 100%

Multiple Choice

IF B IS THE ALLELE FOR BLACK FUR AND b IS THE ALLELE FOR WHITE FUR, WHAT PERCENT WOULD BE BLACK?

• 25%

• 50%

• 75%

• 100%

Multiple Choice

WHAT FRACTION IS HOMOZYGOUS DOMINANT IN THE ABOVE CROSS

• 1/2

• 1/4

• 2/3

• 3/4

Assessment!
Show me what you learned.

Multiple Choice

T - tall and t = short
In the punnett square below, what belongs in the missing square

• tt
• Tt
• Bb
• TT

Multiple Choice

What allele combination should go in the missing box?

• AA
• Aa
• aa
• none of these

Multiple Choice

How many boxes would say BB?

• 1
• 2
• 4
• 0

Multiple Choice

The genotypic ratio here is

• 25% blue eye 75 % brown eye 
• BB = 25% Bb = 50% bb = 25%
• BB= 50 % bb = 50%
• All brown eye

Multiple Choice

The dominant trait is

• yellow pea seeds
• green pea seeds
• there is no dominant seed
• Jolly green giant