(1)Mendel crossed pure-breeding pea plants grown from round seeds with purple flowers with pure-breeding plants grown from wrinkled seeds with white flowers. All the progeny were round seed, purple flowers. Explain this with a suitable genetic diagram.
I drew a punett square and got all to be round seed, purple flower.)
2)When the plants from Q1 were self-pollinated the following season, the following seeds were produced
Phenotype |Genotype|N° of seeds
round,purple | ? |317
round,white | ? |105
wrinkled,purple| ? |106
wrinkled,white | ? |36
a)Which characteristics are not seen in the parents?What does this mean?
b)What is the ratio of phenotypes produced?
c)Draw a genetic diagram justifying these results
d)Cross the heterozygous dominant F1 with the homozygous recessive pea plant. What ratio and phenotypes are produced?Can you think of a use for this?
PLEASE HELP!!!explanations wud be gud
a) Based on the given information, the characteristics not seen in the parents are round, white flowers, wrinkled, and purple flowers. This means that the parents were both pure-breeding for specific traits, but their offspring show combinations of traits that were not present in either parent.
b) To determine the ratio of phenotypes produced, we need to calculate the frequency of each phenotype and compare them.
- Round, purple: 317 seeds
- Round, white: 105 seeds
- Wrinkled, purple: 106 seeds
- Wrinkled, white: 36 seeds
To calculate the ratio, we can divide the number of seeds for each phenotype by the total number of seeds produced:
- Round, purple: 317/564 = 0.5625 (approximately 56.25%)
- Round, white: 105/564 = 0.1856 (approximately 18.56%)
- Wrinkled, purple: 106/564 = 0.1879 (approximately 18.79%)
- Wrinkled, white: 36/564 = 0.0638 (approximately 6.38%)
Therefore, the ratio of phenotypes produced is approximately:
- Round, purple: 56.25%
- Round, white: 18.56%
- Wrinkled, purple: 18.79%
- Wrinkled, white: 6.38%
c) To draw a genetic diagram justifying these results, we need to understand the possible genotypes involved. Let's assign the following letters to the alleles:
- Round (R) and wrinkled (r) for seed shape
- Purple (P) and white (p) for flower color
The parents are crossbred as follows:
Round seed, purple flower (RRPP) x Wrinkled seed, white flower (rrpp)
Using a Punnett square, we can determine the possible genotypes and phenotypes of the offspring. Since all the offspring have round seed and purple flower, it suggests that the genotype is heterozygous for both traits:
| RrPp
---|---
rP | RrPP
rp | RrPp
The results in the Punnett square indicate that the F1 generation is heterozygous for both seed shape and flower color.
d) To cross the heterozygous dominant F1 generation (RrPp) with a homozygous recessive pea plant (rrpp), we use another Punnett square:
| RrPp
---|---
rp | RrPp
rp | RrPp
The possible genotypes and phenotypes of the offspring are:
- Round seed, purple flower (RrPp): 1/4 or 25%
- Round seed, white flower (Rrpp): 2/4 or 50%
- Wrinkled seed, purple flower (rrPp): 1/4 or 25%
One possible use for these genetic ratios could be in plant breeding programs. By understanding the inheritance patterns, breeders can predict the phenotypes of the offspring and select for desired traits, such as round seed and purple flower. This can help in the development of improved crop varieties.