What floral organs would develop in Arabidopsis flower whorls 1, 2, 3, and 4 (in that order) in a mutant in which activity A was expressed in all four whorls and C was expressed in none?
A)$\text { sepal } 3 / 4 \text { petal } 3 / 4 \text { stamen } 3 / 4 \text { carpel }$

B)$\text { sepal } 3 / 4 \text { stamen } 3 / 4 \text { petal } 3 / 4 \text { carpel }$

C)$\text { sepal } 3 / 4 \text { sepal } 3 / 4 \text { stamen } 3 / 4 \text { carpel }$

D)$\text { sepal } 3 / 4 \text { petal } 3 / 4 \text { petal } 3 / 4 \text { sepal }$

E)$\text { sepal } 3 / 4 \text { sepal } 3 / 4 \text { carpel } 3 / 4 \text { carpel }$

Question

What floral organs would develop in Arabidopsis flower whorls 1, 2, 3, and 4 (in that order) in a mutant in which activity A was expressed in all four whorls and C was expressed in none?
A)$\text { sepal } 3 / 4 \text { petal } 3 / 4 \text { stamen } 3 / 4 \text { carpel }$

B)$\text { sepal } 3 / 4 \text { stamen } 3 / 4 \text { petal } 3 / 4 \text { carpel }$

C)$\text { sepal } 3 / 4 \text { sepal } 3 / 4 \text { stamen } 3 / 4 \text { carpel }$

D)$\text { sepal } 3 / 4 \text { petal } 3 / 4 \text { petal } 3 / 4 \text { sepal }$

E)$\text { sepal } 3 / 4 \text { sepal } 3 / 4 \text { carpel } 3 / 4 \text { carpel }$

Quizplus · Accepted Answer

In the ABC model of flower development, A activity specifies sepals in the first whorl and petals in the second when combined with B. Without C activity, A activity would dominate in all whorls, leading to sepals in the first and fourth whorls and petals in the second and third whorls.

What Floral Organs Would Develop in Arabidopsis Flower Whorls 1 sepal 3/4 petal 3/4 stamen 3/4 carpel \text { sepal } 3 / 4 \text { petal } 3 / 4 \text { stamen } 3 / 4 \text { carpel } sepal 3/4 petal 3/4 stamen 3/4 carpel

What Floral Organs Would Develop in Arabidopsis Flower Whorls 1 $\text { sepal } 3 / 4 \text { petal } 3 / 4 \text { stamen } 3 / 4 \text { carpel }$