Why do animal viruses have envelopes and phages rarely do?
A. Since bacteria don't have cell membranes, the bacterial viruses (phages) don't pick them up when they leave the target cells.
B. Phages acquire an outer surrounding that is a part of the cell wall of the bacterium they were created in, rather than an outer surrounding of plasma membrane.
C. Animal viruses will often utilize the envelope in order to fuse with the plasma membrane of a new target cell, gaining entry into the cytoplasm.
D. Animal viruses build the envelope inside of the target cell as they are being replicated, but before the cell breaks open and releases them into the extracellular environment. The envelope is a remnant of this building process.
C
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A newly discovered unicellular microbe has a nucleus containing linear chromosomes and surrounded by a membrane. It has mitochondria, 80s ribosomes, and is covered by cilia. There is no cell wall external to the plasma membrane. This organism most likely would be a/an
A. bacterium. B. protozoan. C. fungus. D. archaeon. E. algae.
Where are blood cells and platelets produced?
A. in red marrow inside of bones B. in yellow marrow inside of bones C. in joints by chondrocytes D. in the liver E. in the spleen
Which of the following classes of antibodies activates the inflammatory response by causing the release of histamine?
A) IgG B) IgE C) IgD D) IgM E) IgA
The West African black rhino, one of four subspecies of rhinoceros, was declared extinct in 2006. Their horns were believed by many to hold medicinal value. What is the most likely reason for the extinction of the West African black rhino?
A. pollution B. habitat loss C. climate change D. introduced species E. overexploitation