Question

In pea plants, purple flowers are dominant over white flowers. Which of the following crosses would create an offspring population with all white flowers?
two hybrid plants
two homozygous recessive plants
homozygous dominant plant with a hybrid plant
homozygous recessive plant with a hybrid plant

-------------------



Choose all the answers that apply.

In some plants, pink flowers are dominant over yellow flowers. If Marlo crosses two hybrids _____.
the ratio of pink to yellow flowers will be 3:1
50 percent of the offspring will be hybrids
none of the offspring will have yellow flowers
three-fourths of the offspring will have the same phenotype
half of the offspring will be homozygous for flower color

Answer 1

Answer:

A) option B, two homozygous recessive plants is correct

B) A, B, D and E  is correct

Explanation:

A) Given purple flowers are dominant over white flowers

Let P represents allele for purple color of flower while p represents white color of flower.

In order to create all white offspring from a cross, the parents must have homozygous recessive genotype i.e pp

Hence, option B, two homozygous recessive plants is correct.

B) Given pink flowers are dominant over yellow flowers. Let “Y” represents allele for pink flower and “y” represent allele for yellow flower

If two hybrid parents with genotype “Yy” are crossed, then following offspring will b eproduced –  

Yy * Yy

YY, Yy, Yy, yy

Out of four , two are hybrid offspring, three genotype i.e YY, Yy, Yy have the same genotype and both YY and yy are homozygous for flower color,  

Hence, option A, B, D and E is correct.

Answer 2

The cross with two homozygous recessive plants would produce a population of all white flowers.

In some plants, pink flowers are dominant over yellow flowers. If Marlo crosses two hybrids:
the ratio of pink to yellow flowers will be 3:1
50% of the offspring will be hybrids
3/4 of the offspring will have the same phenotype
1/2 the offspring will be homozygous for flower colour