Which one of the following is NOT true about ECM? O ECM is composed of an interlocking mesh of fibrous proteins and glycosaminoglycans. O ECM supports cell-to-cell communication and stem cell differentiation. O Proteoglycan complex has a unique bottle brush-like structure. It is positively (+) charged. It is composed glycosaminoglycans and carbohydrates that are attached to the proteins. O ECM is a collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells.

A certain protein is used to activate myosin. If the protein is treated with B-mercaptoethanol, it will not activate myosin. What can you say about the structure of this protein? O The peptide is denatured by B-mercaptoethanol O The peptide does not have a thermodynamically stable configuration O The peptide contains more than one distinct chain O The peptide contains disulfide bonds required for activity

Glucagon is a peptide hormone consisting of 29 residues that are released into the blood. It works with insulin to regulate blood sugar levels, when blood sugar is low, glucagon is a signal to release glucose into the blood from glucose stored in long chains called glycogen. When blood sugar is high, insulin signals to cells to take in glucose and convert into glycogen. Glucagon is an inherently unstructured peptide that does not adopt any definitive fold until it interacts with the glucagon receptor.  Based upon what you know about the structure of CBP’s NCBD region. Which of the following are true? Before binding the structure is at the middle of the protein-folding funnel. Before binding the structure is at the bottom of the protein-folding funnel. It exists as a molten globule B and C A and C

According to the “Hawaiian Punch” principle, different compartments of the secretory and endocytic pathways are topologically equivalent to each other and to the extracellular space. Explain how vesicular transport generates this topological equivalence. These compartments are topologically equivalent because molecules can move between them without having to move out of the cell. Transport vesicles cause this “topological equivalence” because they are responsible for the actual movement of the molecules mentioned above. They break off from one compartment, carrying the necessary molecules, and then fuse to its targeted compartment; thus, making the compartments topologically equivalent.  During mitosis in mammalian cells, the nuclear envelope breaks down into vesicles. Are the topological properties of the cell altered by this event? Justify your answer.