Which of the following is true of viroids?
a. Viroids are typically extremely long and contain numerous genes.
b. There are similarities between the base sequences of viroids and exons, resulting in the hypothesis that viroids evolved from exons.
c. Viroid is the term for a virus that infects plants.
d. Viroids are short pieces of naked RNA.
Ans: d. Viroids are short pieces of naked RNA.
You might also like to view...
Bacterial plasmids and artificial chromosomes are used as ______ to insert foreign DNA into host cells and create recombinant genomes.
A. clones B. vectors C. endonucleases D. subunits
Two populations that have no gene flow between them are likely to
(a) become more different with time. (b) become more alike with time. (c) become more alike if the directional selection pressures are different. (d) stay the same unless mutations occur.
Enkephalins and endorphins are
a. neuromodulators. b. stimulators of brain and nervous activity. c. inhibitors of pain perception. d. neuromodulators and stimulators of brain and nervous activity. e. neuromodulators and inhibitors of pain perception.
What type of mutation involves base changes in the gene, which result in a change in the amino acid without affecting the activity of the resulting polypeptide?
a. insertion b. deletion c. silent mutation d. neutral substitution e. null mutation