Genetics 2 Flashcards
What method did Mendel use for cross-pollination?
Mendel removed the immature stamens of a plant before they produced pollen and dusted pollen from another plant onto the altered flowers.
This method ensured the parentage of new seeds.
What type of traits did Mendel track in his experiments?
Mendel tracked characters that occurred in two distinct, alternative forms, such as purple or white flower color.
This focus allowed for clear observation of inheritance patterns.
What does ‘true-breeding’ refer to in Mendel’s experiments?
True-breeding refers to plants that, over many generations of self-pollination, produce only the same variety as the parent plant.
For example, a true-breeding purple flower plant consistently produces purple flowers.
What was the outcome when Mendel cross-pollinated purple-flowered and white-flowered plants?
All F1 generation plants had purple flowers.
This indicated that the purple flower trait was dominant over the white flower trait.
What is hybridization in Mendel’s terminology?
Hybridization is the mating or crossing of two true-breeding varieties.
This process allowed Mendel to study the inheritance of traits.
What are the generations referred to in Mendel’s experiments?
P generation (parental generation), F1 generation (first filial generation), and F2 generation (second filial generation).
The F1 generation results from the cross of the P generation, and the F2 generation results from the self-pollination of the F1 generation.
What are the two fundamental principles of heredity deduced by Mendel?
The law of segregation and the law of independent assortment.
These principles explain how traits are inherited through generations.
What ratio of purple to white flowers did Mendel observe in the F2 generation?
The ratio was approximately 3 purple to 1 white.
This consistent ratio supported Mendel’s conclusions regarding dominance and recessiveness of traits.
What conclusion did Mendel reach about the recessive trait in the F1 generation?
The recessive trait (white flowers) was not destroyed or blended but was masked by the dominant trait (purple flowers).
This finding challenged the blending hypothesis of inheritance.
What was the blending hypothesis in the context of Mendel’s work?
The blending hypothesis suggested that genetic material from two parents mixes, resulting in offspring with intermediate traits.
Mendel’s findings contradicted this idea by showing dominant and recessive traits.
Fill in the blank: The first filial generation is referred to as the _______.
F1 generation.
True or False: Mendel’s experiments showed that all traits blend together in the offspring.
False.
What did Mendel observe when F1 hybrids self-pollinated?
Both purple-flowered and white-flowered plants appeared in the F2 generation.
This observation was crucial in understanding the inheritance patterns.
What might have happened if Mendel had stopped his experiments after the F1 generation?
He would have missed the basic patterns of inheritance.
Continuing to the F2 generation revealed the reappearance of recessive traits.
What is an allele?
An allele is an alternative version of a gene. So a gene is expressed as a trait e.g. white flower, purple flower. Now there are two versions of the gene and these are known as alleles.
What is a gene?
A gene is a sequence of nucleotides at a specific place, or locus, along a particular chromosome.
