In the Ames test for mutagenicity,
A) reverse mutations convert auxotrophs to prototrophs that survive.
B) colonies are due to forward mutations that convert prototrophs to auxotrophs.
C) cells are treated with mutagen and only cells with no mutations survive.
D) cells are treated with excess amino acids and cells with mutations are killed.
E) rat liver enzymes are present to protect cells from mutation.
A) reverse mutations convert auxotrophs to prototrophs that survive.
You might also like to view...
In vertebrates, the family of myogenic regulatory factors (MRFs) plays a major role in muscle development. This family consists of four related genes which have distinct but overlapping functions. This gene family is represented by only a single gene in Drosophila, called nautilus. You want to know whether nautilus plays a role like all of the MRFs put together, or more like one in particular. What is a quick and easy way to begin to address this question?
A. Compare the DNA and protein sequences of all the genes to determine if nautilus is more similar to one MRF than another. B. Use a DNA microarray to compare gene activation patterns between nautilus and the MRFs. C. Compare the proteome of a cell expressing nautilus to the those of cells expressing each of the MRFs in turn. D. Generate four transgenic Drosophila strains that express the MRFs in a mutant nautilus background. Clarify Question · What is the key concept addressed by the question? · What type of thinking is required? · What key words does the question contain and what do they mean? Gather Content · What do you already know about sequence analysis? Consider Possibilities · Consider the different answer options. Which can you rule out? Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer? Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Edward and Patau syndromes are examples of __________
A. aneuploidy B. allopolyploidy C. autopolyploidy D. translocations
Answer the following statements true (T) or false (F)
1. Mammalian eggs like those of humans undergo holoblastic cleavage and compaction during development. 2. The neural tube or spinal chord is derived from mesoderm. 3. The endoderm is a germ cell layer that tends to cover the embryo. 4. Fate mapping is a valuable tool to establish the type of cells derived from certain undifferentiated cells within an early embryo.
DNA sequence evidence suggests that plants, fungi, and animals arose from different lineages of unicellular protists. This suggests which of the following?
A. Protists evolved before the other three kingdoms. B. Early ancestors to plants, fungi, and animals could interbreed. C. Multicellular organisms arose only once in evolutionary history. D. All unicellular organisms are now extinct. E. The animal, plant, and fungal kingdoms contain some single celled organisms.