Practice Set 4

Question 1

A morphogen is a molecule that:

Answer 1

induces various responses in surrounding tissue in a concentration-dependent
manner.

Question 2

In homeotic mutants:

Answer 2

one body structure has been changed into another.

Question 3

The maternal-effect Bicoid gene codes for:

Answer 3

a DNA-binding transcription factor.

Question 4

Genes with products provided by the female to the egg are called:

Answer 4

maternal-effect genes.

Question 5

The class of genes required for establishing the anteroposterior axis is:

Answer 5

the maternal-effect genes.

Question 6

In Drosophila, the vast majority of A-P axis genes that contribute to pattern formation
encode:

Answer 6

transcription factors.

Question 7

What is the single most important early feature that controls spatial expression of
developmental genes in the Drosophila embryo?

Answer 7

Concentration-dependent response to graded inputs of Bicoid protein diffusion, which
activates expression of other genes such as hunchback.