Answer:
they bind to protein-coupled transmembrane receptors with higher complexity than those found in prokaryotes
Explanation:
G-proteins are proteins found inside the cells that function as molecular switches which are activated by binding to guanosine triphosphate (GTP), while they are inactive by binding to guanosine diphosphate (GDP). The G-proteins bind to G-protein-coupled transmembrane receptors (GPCRs) in the cytoplasmic region. The GPCRs are a very diverse group of proteins that are activated by extracellular molecules ranging from small peptides to large proteins, including pheromones, neurotransmitters, light-sensitive compounds, etc, thereby allowing them to respond to diverse stimuli from the extracellular environment. In consequence, it is reasonable to suppose that the signaling pathways in which G proteins are involved have a higher complexity level than those observed in primitive prokaryotic organisms.
There are several mutations that benefit the organism.A well known example is the antibiotic resistance developed by bacteria, which aid in their survival even when they are exposed to a given antibiotic. A single gene mutation in wild almond trees resulted in a variety that no longer synthesizes amygdalin.
Answer:
The options A, B, and D are all valid.
Explanation:
- The reason is that some proteins require molecular chaperones if they are to fold properly within the environment of the cell. In the absence of chaperones, a partially folded polypeptide chain has exposed amino acids that can form non-covalent bonds with other regions of the protein itself and with other proteins, thus causing nonspecific aggregation of proteins.
- The option A) is correct because the protein you are expressing in bacteria is being made in large quantities, it is possible that there are not enough chaperone molecules in the bacterium to fold the protein. Expressing the protein at lower levels might increase the amount of properly folded protein.
- The option B) is correct as urea should solubilize the protein and completely unfold it. Removing the urea slowly and gradually often allows the protein to refold. Presumably, under less crowded conditions, the protein should be able to refold into its proper conformation.
- The option C) is not correct as treating the aggregate with a protease, which cleaves peptide bonds, will probably solubilize the protein by trimming it into pieces that do not interact as strongly with one another; however, chopping up the protein will also destroy its enzymatic activity.
- The option D) is correct because overexpressing chaperone proteins might increase the amount of properly folded protein.
- The option E) is not correct as heating can lead to the partial denaturation and aggregation of proteins to form a solid gelatinous mass, as when cooking an egg white, and rarely helps solubilize proteins.
