In a frog embryo, gastrulation
A. produces a blastocoel displaced into the animal hemisphere.
B. occurs along the primitive streak in the animal hemisphere.
C. is impossible because of the large amount of yolk in the egg.
D. proceeds by invagination and involution as cells roll over the dorsal lip of the blastopore.
E. occurs within the inner cell mass that is embedded in the large amount of yolk.
D. proceeds by invagination and involution as cells roll over the dorsal lip of the blastopore.
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In individuals with normal blood sugar levels, glucose is reabsorbed into the bloodstream in the kidney by members of the GLUT transporter family, which form an aqueous pore across the membrane through which glucose can move passively. As a result, no glucose is excreted in urine. However, in people with untreated diabetes mellitus, blood sugar levels are high and glucose is often present in the urine. What can explain this occurrence?
A. High blood glucose levels reverse the concentration gradient, allowing untransported glucose to be excreted in urine. B. High blood glucose levels interfere with the coupled transport of water and glucose, allowing untransported glucose to be excreted in urine. C. The GLUT transporters become saturated, allowing untransported glucose to be excreted in urine. D. The GLUT transporters cannot hydrolyze ATP quickly enough for ATP to transport the extra glucose, thereby allowing untransported glucose to be excreted in urine. Clarify Question · What is the key concept addressed by the question? · What type of thinking is required? Gather Content · What do you know about glucose movement through the GLUT transporter? What other information is related to the question? 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?
What structure do myelin sheaths form along?
A. axons B. dendrites C. neuroglia D. cell bodies E. ganglia
Important United States marine laboratories on the Atlantic Coast include all except:
a. Woods Hole Marine Biology Laboratory. b. Rosenstiel School of Marine and Atmospheric Science. c. Duke University Marine Laboratory. d. Friday Harbor Laboratory. e. Harbor Branch Oceanographic Institute.
Which of the following statements is not true of steroid hormones?
1.They include estrogen and testosterone. 2.They rely on membrane-bound receptors. 3.They are lipid soluble. 4.They can interact with target cell DNA.