How do steroid hormones differ in action from peptide and protein hormones?
What will be an ideal response?
Steroids are soluble in the phospholipid bilayer of membranes so they often enter the cell and the nucleus, having direct effects on transcription. Proteins and peptides are too large to cross the membrane. They act by binding to receptors on the membrane surface, triggering the release of a second messenger, usually cyclic-AMP.
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In peas, Mendel found that tall plants and yellow peas are dominant. The phenotype for a pea plant
with the genotype TTyy would be: a. heterozygous. b. Ty. c. short with yellow peas. d. tall with green peas. e. tall with yellow peas
The drug used for several protozoan infections is
A. metronidazole. B. sulfa drugs. C. griseofulvin. D. nystatin. E. amphotericin B.
Polydactyly is a dominant trait that results in extra fingers and toes in humans. A man with polydactyly marries a woman with 10 fingers and toes. They have a child that has a normal number of digits. The phenotype of the man's father is unknown, but his mother has a normal phenotype. What are the genotypes of the married couple? (D = polydactyl allele; d = wild type allele)
A. woman DD; man Dd or dd B. woman DD; man dd C. woman Dd; man dd D. woman dd; man Dd E. woman dd; man DD
Which of the following statements is CORRECT regarding Figure 6.1?
A. Cells are actively reproducing only during the stage represented by B. B. The population is increasing arithmetically during the stage represented by B. C. Cells are most susceptible to antibiotics during the stage represented by D. D. Cells are alive but not reproducing during the stage represented by A. E. No new cells are being produced during the stage represented by C.