Briefly explain the role of Malpighian tubules in arthropods. What will be an ideal response?
Malpighian tubules absorb uric acid, salts, water, and wastes from the hemolymph. Some
materials are selectively reabsorbed into the hemolymph, and the rest is emptied into the gut.
Uric acid is excreted as a paste, and thus minimal water is lost. This efficient conservation of
body fluids has contributed to the success of insects.
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In garden peas, one pair of alleles controls the height
of the plant, and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a dwarf plant with white flowers produces 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white. What is the genotype of the parents? What will be an ideal response?
A fastidious organism might be grown on which of the following types of media?
A) transport media B) reducing media C) enriched media D) differential media E) selective media
Which of the following statements about generalized transduction is false?
A. "Head full" packaging always places only phage DNA into the phage head during phage packaging in generalized transduction. B. Generalized transduction always involves lytic phage. C. Generalized transduction can be used to map bacterial genes. D. Genes that are close together on the bacterial chromosome will have a relatively large cotransduction frequency. E. Two recombination events are necessary to integrate the transferred DNA during generalized transduction.
A phosphatase is capable of dephosphorylating molecules. What would this enzyme do in a signal transduction pathway that used a kinase cascade?
A. Turn off the cascade. B. Activate the cascade. C. Phosphorylate a receptor. D. Serve as a ligand for the receptor. E. Phosphorylate a transcription factor.