Retroviruses have a +ssRNA as their genome. In order to complete an infection, they must first make a ________ molecule, which they use to direct the synthesis of mRNA.
A. -ssRNA
B. dsDNA
C. dsRNA
D. DNA:RNA hybrid
Answer: B
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A woman can best predict the time of an upcoming ovulation by testing each day for ______.
A. luteinizing hormone B. follicle-stimulating hormone C. estrogen D. progesterone
Griffith's experiment demonstrated transformation because a mouse injected with live R and heat-killed S strains of Streptococcus pneumoniae resulted in death of the mouse and the isolation of live R as well as live S cells. Hypothesize as to the type of cells that Griffith would have observed if transformation had NOT occurred.
A. Griffith would have isolated both live R and heat-killed S cells from the mouse host. B. Griffith would have isolated no cells from the mouse host. C. Griffith would have isolated only live R cells from the mouse host. D. Griffith would have isolated only live S cells from the mouse host.
Organs form and begin to function during the ____ period.
A. embryonic B. amniotic C. fetal D. chorionic E. gastrulation
Which of the following statement concerning structural genes is FALSE?
a. Most structural genes encode a single polypeptide. b. Coding regions always contain introns. c. There may be noncoding regions at the end of the gene. d. A single DNA sequence can sometimes code for more than one polypeptide. e. All of the above are true