Biology Topic Practice
Punnett Square Practice
Punnett squares are the key tool for predicting the outcome of genetic crosses.
What is the probability of two heterozygous parents (Bb x Bb) having a recessive (bb) child?
What is Punnett Square Practice?
"Monohybrid inheritance is the inheritance of a single characteristic controlled by one gene."
Question 1
What is an allele?
Question 2
What is meant by a dominant allele?
Question 3
Which genotype is heterozygous?
Generic Crosses
A genetic cross looks at the alleles of the parents.
Probability can be expressed as a ratio (1:3), a percentage (25%), or a fraction (1/4).
Always use capital letters for dominant and lowercase for recessive alleles.
Exam Tip
If an allele is dominant, you only need one copy of it to show that characteristic.
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