Exam 20: Genes and Development

An example of gene regulation at the level of translation is the ability of the Bicoid protein to repress translation of caudal mRNA and for Nanos protein to repress translation of hunchback mRNA.

In humans, the three germ layers are established when the:

The sequence and actions of genes controlling development of the anterior-posterior axis of Drosophila illustrate:

Normal development requires proper positioning of macromolecules in the oocyte.

Which of the following graphs illustrates the relationship between the amount of Bicoid protein and the translation of hunchback mRNA in the Drosophila embryo?

Evolutionarily conserved molecules:

Mature cells are terminally differentiated. What could cause this permanent change?

In Drosophila, absence of Bicoid protein results in larvae missing anterior segments and absence of Nanos protein results in larvae missing posterior segments. Suppose you inject Nanos protein into the anterior region of early embryos lacking Bicoid. The expected result would be:

In the Drosophila embryo, segment-polarity genes govern the partitioning of the anterior-posterior gradient into segments.

Which of the following is TRUE of the APETALA-2 gene?

Which of the following transcriptional regulators prevents the expression of its target gene when the amount of the transcription factor gets too high?

Many valuable horticultural varieties of plants, including roses, rhododendrons, junipers, geraniums, and so on, are commonly propagated by inducing roots to form on cuttings taken from branch tips. This method involves cutting a few inches from the tip of a branch and inserting the cut end into moist sand or other substrate. Under the right conditions, roots may form from the cut end, giving a new plant generated from the stem cutting. Which of the following hypotheses is the LEAST likely, given the observation of roots forming from a cut stem?

Differentiating cells delete the DNA for genes they do not need.

A mutation in a gene that results in an inactive protein product is known as a _____ mutation.

Nanos _____ caudal mRNA translation.

A mutation is found in C. elegans that causes the organism to have no vulval opening cells or any vulval supporting cells. What could this mutation be?

In the graph shown here, the dashed line shows the level of mRNA for a certain protein, Prot4, at various positions along the anterior-posterior axis of an insect embryo. The solid line represents the level of a regulatory protein that controls translation of the Prot4 mRNA. If the regulatory protein stimulates translation of the Prot4 mRNA, then which graph shows the expected level of Prot4 across the embryo?

A new mutation is discovered in Drosophila in which a group of contiguous larval segments are missing. What kind of gene is it?

Which of the following statements is TRUE regarding Arabidopsis?

Shown here are four ligands (M, H, K, and L) and their corresponding receptors along with four genes (S, T, U, and V) whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene repression. Which ligand acts as a signal resulting in both genes U and V being active?