Genetics

Before Mendel how did people think you got your traits

• equal blending from each parent

• more from the dad

• more from the mom

• from a stork

If you cross two heterozygous traits (Rr x Rr), what ratio will you get between offspring with the dominant and recessive phenotypes

• 1:1

• 2:1

• 3:1

• 4:1

Mendel concluded that traits are 

• not inherited by offspring
• inherited by the passing of factors from parents to offspring
• determined by dominant factors only
• determined by recessive factors only

When Mendel crossed true-breeding tall plants with true-breeding short plants, all the offspring were tall because

• the allele for tall plants is recessive.
• the allele for short plants is dominant.
• the allele for tall plants is dominant.
• they were true-breeding like their parents.

In the P generation, a tall plant was crossed with a short plant. Short plants reappeared in the F2 generation because

• some of the F2 plants produced gametes that carried the allele for shortness.
• the allele for shortness is dominant
• the allele for shortness and the allele for tallness segregated when the F1 plants produced gametes.
• they inherited an allele for shortness from one parent and an allele for tallness from the other parent.

A Punnett square shows all of the following EXCEPT

• all possible results of a genetic cross.
• the genotypes of the offspring.
• the alleles in the gametes of each parent.
• the actual results of a genetic cross.

A pea plant that has two different alleles for the same trait is said to be ____________________.

• P
• heterozygous
• Tt
• F2

An organism’s gametes have ____________________ the number of chromosomes found in the organism’s body cells.

• half
• 23
• twice
• 4

How many recessive alleles for a trait must an organism inherit in order to show that trait?

• 2
• 1
• 4
• 0

What pattern of inheritance is shown in this image?

• Codominance
• Incomplete dominance
• Polygenic traits