Polypeptides must be sorted after translation. Does protein sorting occur in both prokaryotes and eukaryotes? Describe the process of protein sorting and explain how the signal sequence is involved
What would you expect to see if the signal sequence has been mutated or deleted?
Protein sorting is a process that uses signal sequences of amino acids at the N-terminal end of a polypeptide to sort proteins and direct them to their cellular destinations.
Protein sorting is needed in bacterial cells because of the many proteins specifically destined for
the cell membrane. In eukaryotes, however, protein sorting is far more complex than in bacteria; proteins are dispatched to particular cellular organelles, such as the chloroplast, mitochondrion, lysosome, and nucleus, and certain proteins are secreted from the cells. If the signal sequence is mutated, proteins may not be secreted or processed properly and will begin to accumulate within
the cell. Ultimately, this will result in cell death and impaired protein secretion.
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Aseptic technique refers to
A) the microbial inoculum placed into a test tube or onto a Petri plate. B) a series of practices to avoid contamination. C) the autoclave and other sterilizing procedures. D) cleanliness in the laboratory.
Choose the item in column 2 that best matches each item in column 1. You may use a column 2 item more than once
A) active transport and indirect active transport B) simple diffusion and facilitated diffusion C) active transport D) none of the listed processes E) simple diffusion F) facilitated diffusion and active transport G) facilitated diffusion (passive transport) H) indirect active transport 1) requires direct ATP hydrolysis 2) depends on high partition coefficient of the solute 3) driven by an ion gradient 4) transports glucose across membranes 5) Na+/glucose symport 6) Na+/K+ ATPase pump 7) transports small, nonpolar molecules 8) transports ions up concentration gradients 9) transports water across membranes 10) direction of transport depends on the concentration gradient 11) requires ligand binding and therefore Km for transport can be calculated
Certain proteins can bind to specific DNA regulatory sequences by entering
A. DNA's minor groove by using DNA polymerase and reading the nucleotide base pairs. B. the major groove of the DNA and reading the nucleotide base pairs. C. the major groove of RNA and reading the nucleotide base pairs. D. the minor groove of the DNA and reading the nucleotide base pairs. E. DNA's major groove by using DNA polymerase and reading the nucleotide base pairs.
The common name for the disease caused by human parvovirus B19 is
A. kissing disease. B. fourth disease. C. fifth disease. D. shingles. E. Reyes' syndrome.