L6 MENDEL'S MONOHYBRID CROSSES & PUNNETT SQUARE

What was the P (Parental) generation in Mendel’s first experiment?

A cross between a purebred tall plant (TT) and a purebred short plant (tt)

What is a monohybrid cross?

A genetic cross between two individuals that differ by one trait (e.g., plant height)

What was the result of the F1 generation in Mendel’s first experiment?

All offspring were tall (100% tall phenotype)

What conclusion did Mendel draw from the F1 results?

One trait is dominant over the other

What is Mendel’s First Law of Inheritance?

Law of Dominance – In a heterozygous organism, only the dominant trait is expressed.

What did Mendel do in his second experiment?

He self-pollinated the hybrid tall plants (Tt) from the F1 generation.

What were the F2 generation results?

75% were tall and 25% were short

What consistent pattern did Mendel observe across other traits?

The same 3:1 ratio appeared (Mendelian Ratio)

What is Mendel’s Second Law of Inheritance?

Law of Segregation – Two alleles for each trait separate during gamete formation.

How does the Law of Segregation explain gamete formation?

Each gamete receives only one allele of each pair due to separation during meiosis

What did Mendel deduce about alleles from his experiments?

Every organism has two alleles per trait, one inherited from each parent

What happens to allele pairs during gamete production?

They segregate so that each gamete carries only one allele

What is expressed when an organism inherits two different alleles?

The dominant allele is fully expressed; the recessive allele is masked

Monohybrid Cross

A genetic cross of two individuals that differ by one trait

Genetic Cross

Any type of deliberate breeding between a male and a female to produce offspring that carry the genetic material of each parent

Hybrid

An offspring of parents that have different traits