Cell surface molecules are labeled with a fluorescent tag and then a portion of them are bleached with a laser beam. What would one observe after the cell is incubated for a few minutes?
A. The bleached molecules would disappear into the cell.
B. The bleached molecules would diffuse laterally through the membrane and intermix with unbleached molecules.
C. The bleached molecules would remain in the spot where bleaching occurred.
D. All the bleached molecules would flip-flop across the cell membrane.
E. All of the choices are correct.
B. The bleached molecules would diffuse laterally through the membrane and intermix with unbleached molecules.
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Learning has the most influence on behavior when _____
A) making mistakes does not result in death B) animals reproduce asexually C) animals have enormous cognitive ability D) making mistakes result in death
Interrupting the night with a flash of light can trigger flowering in a long-day plant. Why doesn't introducing a short period of darkness during the day cause a short-day plant to flower?
A. Sunlight contains enough far-red light to inhibit phytochrome induction of flowering. B. A brief dark period is not sufficient to trigger flowering. C. Phytochrome is only active in the dark. D. The circadian clock is less responsive during the day than at night. E. The phytochrome response also requires cool nighttime temperatures. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about long-day and short-day plants? What other information is related to the question? Choose Answer Given what you now know, what information 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?
Radioactive dating techniques have demonstrated that Earth was formed approximately ________ years ago
A) 10 billion B) 46 million C) 4.6 million D) 4.6 billion
When blood glucose levels rise, insulin signals cells to take up glucose, removing it from the blood. Diabetes mellitus is a disorder caused by a dysfunction in the insulin signaling system. There are two types of diabetes
People with type 1 diabetes must take insulin regularly, usually through injection. People with type 2 diabetes are not helped by supplemental insulin. What does this tell you about where the defect might be in these two disorders? A) Type 1 diabetes is probably caused by defective insulin receptors. B) Type 2 diabetes is probably caused by underproduction of insulin. C) Type 1 diabetes is probably caused by underproduction of insulin. D) Type 2 diabetes is probably caused by overproduction of insulin.