If goats are crossed with sheep, embryos will form but cease development and spontaneously abort. This is an example of
A. a prezygotic mechanism.
B. hybrid inviability.
C. hybrid sterility.
D. hybrid breakdown.
E. spermatic behavior.
B. hybrid inviability.
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Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its end, the RNA genome has a viral protein (VPg) instead of a cap
This is followed by a nontranslated leader sequence, and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment? A) Host cell ribosomes only translate the viral code into short polypeptides. B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. C) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. D) The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.
Monocots and eudicots differ in how xylem and
phloem are distributed in ground tissue, in the number of petals in flowers, and in the number of __________. Fill in the blank(s) with the appropriate word(s).
The E. coli enzyme responsible for creating unsaturated bonds from saturated bonds in the cell membrane fatty acids at a lower environmental temperature is ________
Fill in the blank with correct word.
Which process could have allowed the nucleomorphs of chlorarachniophytes to be reduced, without the net loss of any genetic information?
A) conjugation B) horizontal gene transfer C) phagocytosis D) meiosis