Agenetic mutation that causes a codon that should code for a specific amino acid to be changed into a stop codon results in a shortened protein product and is known as
a.
a frame shift mutation.
b.
a chromosomal mutation.
c.
a nonsense mutation.
d.
a silent mutation.

One function of the poly-a tail on eukaryotic mrna sequences is to the mrna be transported from the nucleus to the cytoplasm. prokaryotic mrna also has a poly-a tail. choose the best explanation of the prokaryotic poly-a tail. a. prokaryotic poly-a tails are composed of a different molecular structure compared with eukaryotic poly-a tails. b. prokaryotic poly-a tails have the same functions as eukaryotic poly-a tails, because this process is highly conserved throughout different species. c. prokaryotic poly-a tails aren't important, because prokaryotes don't have nuclei. d. prokaryotic poly-a tails have other functions,because prokaryotes don't have nuclei.

The small molecule cyclic amp (camp) takes about 0.2 second to diffuse 10 μm, on average, in a cell. suppose that camp is produced near the plasma membrane on one end of the cell; how long will it take for this camp to diffuse through the cytosol and reach the opposite end of a very large cell, on average? assume that the cell is 200 μm in diameter.

The model illustrates a process by which a substance is taken up by a cell. which statements describe the process? a. the model shows the process of endocytosis. b. the process shown in the model requires energy from the cell. c. the cell membrane in the model remains intact throughout the process. d. the model shows the process of facilitated diffusion.