Exam 20: Genes and Development

Homeotic genes encode very important transcription factors that specify the identity of body parts or segments during development. For example, the development of legs on thoracic segments T1, T2, and T3 and wings on segment T2 is controlled by homeotic genes.

Why does a mutation in a maternal-effect gene affect the offspring of mutant females and not the mutant female herself?

Which of the following organisms possess simple eye "pits," which, although not morphologically similar to mammalian eyes, are still capable of sensing light?

A cell in the epithelium lining the human gut is very different in structure and function from, for example, a white blood cell. How would you describe the genetic basis for this difference?

In the ABC model of floral development, A, B, and C stand for the activities of different:

Imagine that a researcher is looking at a mutant Arabidopsis plant that only produces carpels and sepals; stamens and petals are absent. Which of the following statements must be TRUE regarding this plant?

All transcription factors-like Pax6-are normally transcriptional activators; only mutated forms of transcription factors act as transcriptional repressors.

Extracellular molecules activating membrane proteins that in turn activate molecules inside the cell that control differentiation is an example of signal:

The developmental pathway of each whorl of a developing Arabidopsis flower is determined by the specific:

The early cell divisions of human development differ from other mitotic cell divisions in that:

Using the natural processes of cell growth and development to replace diseased or damaged tissue is called:

CopyCat, the first cloned cat, was derived from an ovarian cell from a female calico cat. But CopyCat was not an exact copy, as she herself was not calico. This result implies that:

The Pax6 gene is a master regulator of eye development, but it does not result in potato eyes. Why not?

A mutation in a gene that results in it being expressed in the wrong place or at the wrong time is known as a _____ mutation.

Which of the following CORRECTLY pairs a germ layer with the cells that will form from it?

Each answer option below lists terms that classify cell types according to their developmental potential. Which of the options lists the terms from those capable of differentiating into the greatest number of different specialized cells to those capable of differentiating into the least number of different specialized cells?

The Pax6 gene acts as a master regulator of eye development. If a Pax6 gene from a mouse were engineered to be expressed in the antenna of Drosophila, what would you expect to observe?

CopyCat, the first cloned cat, was derived from an ovarian cell from a female calico cat. But CopyCat was not an exact copy, as she herself was not calico. This result implies that, if the donor female were also heterozygous for an X-linked harmful mutation causing muscle degeneration, the probability of a clone being affected is:

The fertilized egg is totipotent, which means:

Hierarchical development proceeds such that each successive group of genes that are expressed refine and narrow the pattern of differentiation generated by previous groups.