Introduction to Genetics

The table below summarizes Mendel's results for the F2 generation. What number should replace the letter x in the "Seed colour" row?

2,001

Tall pea plants are dominant over short pea plants. If there are 200 short plants in the F2 generation from a cross that followed Mendel's methods, about how many plants will be tall in that generation?

600

Which of Mendel's generations was allowed to self-pollinate?

F1 generation

If Mendel had crossed a true breeding dominant plant with a true breeding recessive plant, in which of the three generations is the recessive trait visible?

P generation and F2 generation

Mendel was able to study seven traits in all the pea plants in each generation. Which of his hypotheses allowed him to analyze each trait separably?

When gametes are formed, each gamete carries only one allele for the gene.

What is a gene?

a section of DNA that codes for a specific trait

Mendel's pea plants had either purple or white flowers. This means that the plants

have two alleles for the gene.

What controls traits and inheritance?

nucleic acids

If a scientist wanted to follow Mendel's experiment with a different kind of plant, which type of plant would she examine?

A plant that has only two alleles for a trait.

Why did Gregor Mendel use pea plants in his experiments?

Peas have characteristics that have two forms.

Cystic fibrosis is a genetic disorder. It is a recessive trait that is determined by two alleles. Suppose two parents each carry at least one recessive allele, but neither of them has cystic fibrosis. Which statement reflects the likelihood of a child of those parents having cystic fibrosis?

The child may or may not have the disease because a recessive gene from each parent may be passed on.

Which statement describes the offspring of the F1 generation when crossing a pea plant that is true breeding for green seeds with a pea plant that is a true breeding for yellow seeds?

The offspring will inherit one gene from each parent.

During an experiment, a scientist crosses a pea plant that has purple flowers with a pea plant that white flowers. The plants that result from this cross in the F1 generation have both purple and white flowers. What can the scientist conclude?

The plants in the P generation were not true-breeding.

Some people have freckles, and some people do not have freckles. If a child has freckles, at least one parent has freckles. However, the child may have a sibling that does not have freckles. Which statement best describes the presence of freckles?

There are two alleles for freckles.

The table below summarizes the traits that Mendel examined during his experiments. What do these characteristics all have in common?

They can all be easily observed.

Which is the best example of a hypothesis leading to new experimental methods?

Thomas Hunt Morgan continued the genetic research of Gregor Mendel, but Morgan used fruit flies.