Question

Помогите,просто умоляю по биологии решить тест даю 40 баллов,буду оооочень благодарна если решите(заранее спасибо) 1 вариант. 1.Полосатая окраска кабачков наследуется как рецессивный признак.Какое потомство от скрещивания двух гетерозиготных растений с гладкой окраской? 2.Дурман, имеющий пурпурные цветы,дал при самоопылении 30 потомков с пурпурными и 9 с белыми цветами.Какие выводы можно сделать о генотипе цветов цветков. 3. У растения "ночная красавица" наследование окраски цветов осуществляется по неполному доминированию.Гомозиготные организмы имеюткрасные или белые цветы,а у гетерозигот они розовые.При скрещивании двух растений половина гибридов имела розовые,а половина-белые цветы.Определить генотипы и фенотипы родителей.

Answer 1

1. 75% - гладкие, 25% - полосатые
2. Скрещивали пурпурные гетерозиготные растения.
3. Скрещивали розовую гетерозиготу и белую рецессивную гомозиготу.

Answer 2

Inheritance of Striped Color in Zucchini Plants

The striped color in zucchini plants is inherited as a recessive trait. When two heterozygous plants with smooth coloration are crossed, what will be the offspring's phenotype and genotype?

The inheritance of traits in plants follows the principles of Mendelian genetics. In this case, the striped color in zucchini plants is a recessive trait, meaning that it is only expressed when an individual has two copies of the recessive allele.

When two heterozygous plants with smooth coloration (genotype: Ss) are crossed, the possible genotypes and phenotypes of the offspring can be determined using a Punnett square.

| | S | s | |-----|-------|-------| | S | SS | Ss | | s | Ss | ss |

From the Punnett square, we can see that there is a 25% chance of obtaining offspring with the genotype SS (homozygous dominant) and a smooth coloration phenotype, a 50% chance of obtaining offspring with the genotype Ss (heterozygous) and a smooth coloration phenotype, and a 25% chance of obtaining offspring with the genotype ss (homozygous recessive) and a striped coloration phenotype.

Therefore, the offspring from the cross of two heterozygous plants with smooth coloration will have a 25% chance of having striped coloration and a 75% chance of having smooth coloration [[1]].

Genotype of Flowers in Datura Plants

In the case of Datura plants, there is a variety called "Datura stramonium" or "jimsonweed" that has purple flowers. When self-pollination occurs, 30 offspring have purple flowers and 9 offspring have white flowers. What conclusions can be drawn about the genotype of the flower color?

To determine the possible genotypes of the flower color, we can use the principles of Mendelian genetics and perform a chi-square test.

Let's assume that the purple flower color is determined by a dominant allele (P) and the white flower color is determined by a recessive allele (p).

From the given information, we know that 30 offspring have purple flowers and 9 offspring have white flowers. This gives us a total of 39 offspring.

Let's denote the genotype of the purple-flowered offspring as PP or Pp and the genotype of the white-flowered offspring as pp.

If we assume that the observed numbers of purple and white-flowered offspring fit the expected ratios based on Mendelian genetics, we can calculate the expected numbers of each genotype.

According to Mendelian genetics, when two heterozygous individuals (Pp) are crossed, the expected ratio of offspring with purple flowers (PP or Pp) to offspring with white flowers (pp) is 3:1.

Using this ratio, we can calculate the expected numbers of each genotype:

- Expected number of offspring with purple flowers (PP or Pp): (3/4) * 39 = 29.25 - Expected number of offspring with white flowers (pp): (1/4) * 39 = 9.75

Comparing the expected and observed numbers, we can perform a chi-square test to determine if the observed numbers fit the expected ratios.

The chi-square test formula is: X^2 = Σ((O - E)^2 / E), where O is the observed number and E is the expected number.

Calculating the chi-square value:

X^2 = ((30