Punnett square In a certain plant, red flowers are dominant over white flowers. A plant heterozygous for red flowers and a plant with white flowers are crossed. Which of the following is the expected proportion of phenotypes in the next generation?
A. 4 red, 0 white
B. 2 red, 2 white
C. 1 red, 3 white
D. 3 red, 1 white
We use the Punnet square to find the population of the resulting offspring from the crossing of a plant heterozygous for red flowers with a plant with white flowers.
Let R be the dominant allele for red while r is the recessive allele color for red. Therefore, the phenotype for parent 1 which is heterozygous for red flower will be Rr and the second parent with white flowers will be rr.
We cross the two phenotypes in a Punnet square as follows
|
|
r |
r |
|
R |
Rr |
Rr |
|
r |
rr |
rr |
Thus, there are 2 heterozygous offspring with red flowers and 2 offspring with white flowers.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: Which of the following are structural features of the trachea?
A. C-shaped cartilage
B. Smooth muscle fibers
C. Cilia
D. All of the above
Answer Explanation
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Q #2: Nitrogen gas is an extremely stable molecule because its structure contains which of the following?
A. Resonance bonds
B. Ionic bonds
C. Triple covalent bonds
D. Hydrogen bonds
Answer Explanation
The Lewis structure of nitrogen gas is shown below. Triple bonds are stronger than double or single bonds. Therefore, we can infer that the triple bond between the two nitrogen atoms makes nitrogen gas more stable.
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Q #3: Which of Mendel's laws or principles states that gametes carry one allele for each trait?
A. law of segregation
B. independent assortment
C. gene segregation
D. phenotype assortment
Answer Explanation
