In the classic experiments by Bracht and Hammerling, the nucleus of Acetabularia was removed, the
cap was cut off, a nucleus of a different species was inserted, and the cap was allowed to regenerate.
The new cap was then removed. After the second regeneration, the cap was observed, and the
following conclusion was made:a.
The shape of the cap was controlled by the nucleus, thus, the nucleus was the control
center of the cell.
b. The shape of the cap was under the control of the stalk, which produced a control
substance.
c. The shape of the cap was independent of both the stalk and the holdfast.
d. The "cren" caps were defective due to some mutation in the cap. Thus, "cren" caps are
independent of control from both the base and the holdfast.
e. At the time no conclusion could be made because in the early 20th century, biologists did
not know about the composition of DNA.
A
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Aquaporins have been identified in the epithelium of the large intestine. What is the function of these aquaporins?
A) to secrete water into the large intestine B) to reabsorb water from the large intestine C) to regulate solute transport from the feces to the body D) to release hormones involved in regulating digestive processes of the large intestine
Mangroves encourage the erosion of soils on coastlines
Indicate whether the statement is true or false.
Associations of fungi and plant roots are called
A. root forks. B. mycorrhizae. C. lichens. D. gnetophytes. E. rhizoids.
The time it takes for half of a radioisotope’s atoms to
decay a. cannot be calculated. b. is used to construct the geologic time scale. c. is its half-life. d. is the same for uranium 238 and carbon 14. e. is all of these.