Complete the following concept map to test your knowledge of gene regulation.

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Which of the following methods of gene regulation do eukaryotes and prokaryotes have in common?

a. Elaborate packing of DNA in chromosomes

b. Activator and repressor proteins, which attach to DNA

c. The addition of a cap and tail to mRNA after transcription

d. Lac and trp operons

A homeotic gene does which of the following?

a. It serves as the ultimate control for prokaryotic operons.

b. It regulates the expression of groups of other genes during development.

c. It represses the histone proteins in eukaryotic chromosomes.

d. It helps splice mRNA after transcription.

Which of the following is a valid difference between embryonic stem cells and the stem cells found in adult tissues?

a. In laboratory culture, only adult stem cells are immortal.

b. In nature, only embryonic stem cells give rise to all the different types of cells in the organism.

c. Only adult stem cells can differentiate in culture.

d. Embryonic stem cells are generally more difficult to grow in culture than adult stem cells.

The control of gene expression is more complex in multicellular eukaryotes than in prokaryotes because __________. (Explain your answer.)

a. Eukaryotic cells are much smaller

b. In a multicellular eukaryote, different cells are specialized for different functions

c. Prokaryotes are restricted to stable environments

d. Eukaryotes have fewer genes, so each gene must do several jobs

Your bone cells, muscle cells, and skin cells look different because

a. Each cell contains different kinds of genes.

b. They are present in different organs.

c. Different genes are active in each kind of cell.

d. They contain different numbers of genes.

All your cells contain proto-oncogenes, which can change into cancer-causing oncogenes. Why do cells possess such potential time bombs?

You obtain an egg cell from the ovary of a white mouse and remove the nucleus from it. You then obtain a nucleus from a liver cell from an adult black mouse. You use the methods of nuclear transplantation to insert the nucleus into the empty egg. After some prompting, the new zygote divides into an early embryo, which you then implant into the uterus of a brown mouse. A few weeks later, a baby mouse is born. What color will it be? Why?

Mutations can alter the function of the lac operon (see Module 11.1). Predict how the following mutations would affect the function of the operon in the presence and absence of lactose:

a. Mutation of the regulatory gene; repressor cannot bind to lactose.

b. Mutation of operator; repressor will not bind to operator.

c. Mutation of regulatory gene; repressor will not bind to operator.

d. Mutation of promoter; RNA polymerase will not attach to promoter.

It took three sheep to create the clone Dolly: A blackface sheep donated the egg, a whiteface sheep donated the mammary cells from which the nucleus was taken, and a blackface sheep served as surrogate. Assuming face color is genetically determined, what color face did Dolly have?

The success of an experiment often depends on choosing an appropriate organism to study. For example, Gregor Mendel was able to deduce the fundamental principles in genetics in part because of his choice of the pea plant. Reviewing Module 10.1, how did Hershey and Chase take advantage of the unique structural properties of bacteriophage T2 to determine the genetic material?

Each scientist works as part of a broader community of scientists, building on the work of others. Scientific advances often depend on the application of new technologies and/or on new techniques applied to an existing problem.

What improvements to existing cloning methods did Wilmut make that allowed him to successfully clone Dolly the sheep from an adult cell?