Question

21: Met c aion of the Polamino 21. Which of the following would NOT Change the structure and function of a protein A Methylation of a protein B. Lipid modification of a protein C. Change in the length of the Poly A tail of the mRNA transcript encoding a protein D. Change in the position of reactive amino acids E. Proteolysis 22. Two peptides have almost the exact same primary structure, except that one has about 10 fewer amino acids at the amino-terminus (N-terminus) of the protein. What is a possible explanation for the protein that is missing those 10 amino acids? A. An alternative Poly-A tail addition site B. Leaky scanning occurred C. Differential glycosylation of the protein D. Inefficient folding by chaperone proteins E. All of the above are correct answers 23. A protein called Ras is tethered (linked) to the plasma membranes of stem cells where it participates in signal transduction pathways that affect stem cell proliferation. Which of the following covalent modifications would be responsible for tethering (linking the Ras to the membrane? A Phosphorylation B. Glycosylation c. Lipid modification D. Ubiqutlylation E Acetylation 24. What do transmembrane proteins in the peroxisome, nucleus, and mitochondria all have in common? A They are all co-translationally inserted into the membrane B. They are all post-translationally inserted into the membrane C. Their transmembrane spanning regions are composed of highly hydrophilic amino acids D. They do not use a protein translocator for membrane insertion E. They do not have anything in common 25. You are studying a disease that occurs in individuals when an ER transmembrane protein call DZR is not inserted into the ER membrane of neurons. You find that the D2R gene is transcri and the mRNA is exported out of the nucleus. You also notice that all other ER transmembra proteins are inserted into the ER membrane properly. Which of the following could still be the cause of this disease? A The D2R gene has mutations in start/stop transfer sequences that prevent recognition by the ER protein translocator B. The S' cap is not added to the DZR mRNA C. The ER protein translocator is not present in this cell D. A and Care both possible

Answer 1

Answer:

21) B

22) E

23) B

24) B

25)A

Protein Structure without lipids molecules change