Mucins found on adenocarcinoma cells carry O-glycans terminated with sialic acids (such as the Sialyl Tn antigen) that are smaller and less branched than O-glycans found in healthy epithelial cells. Based on what you know about the biosynthetic pathway for O-glycans, explain this observation.

Your friend's genetic test revealed that they have a rare mutation - they lack the glycotransferase responsible for adding the terminal fucose molecule to the oligosaccharide on the surface of red blood cells. What is the consequence for a blood transfusion - which blood groups can they receive donations from, if any? Why? Although they lack the terminal fucose normally found on the surface of red blood cells, can you make any predictions as to wheter they also have or lack the Galactose or GalNAc found on A or B blood types? Your friend suggested a simpler way to test for this type of mutation. They have suggested taking a Fucosidase (a type of glycosidase) and mutating it so that the active site was no longer functional - they claim this would endow the protein with the properties of a lectin. Does their claim make any sense?

Amoeboid cells that migrate through our tissues, such as the class of white blood cells known as neutrophils, often do so in a directed manner, triggered, for instance, by chemical signals released by pathogens such as bacteria. Directed migration in response to a chemical stimulus is known as chemotaxis. Part of an efficient chemotactic response is the ability of cells to polarize. As is the case with our structurally-polar polymers like F-actin or microtubules, polarization here refers to an asymmetry in the cells, rather than an electrical charge. In this case, it involves one part of the cell becoming the “front” (or leading edge) and another the rear. In a well-polarized, migrating cell, it’s been observed that an active form of Rac (which, in turn, can activate ARP 2/3) is concentrated towards the front of the cell, whereas an active form of Rho (which, in turn, can activate formin, inhibit cofilin/ADP, and activate myosin II) is found toward the rear of the cell. Based on your…

Classify the following enzymes: Oxidoreductase, Hydrolase, Transferase, Lyase, Ligase, Isomerase 1. Sucrase                                                                 - 2. Trypsin                                                                  - 3. Catalase                                                               - 4. Aspartate aminotransferase                            - 5. Cellulase                                                              - 6. Ptyalin                                                                  - 7. Lactase                                                                 - 8. Creatinine phosphokinase                               - 9. 5- alpha reductase                                            - 10. Aminopeptidase                                             -