Tutor profile: Larisa I.
What property of water allows it to have a very high boiling point?
Hydrogen bonds! Water is made up of oxygen and hydrogen atoms, allowing it to form hydrogen bonds between molecules. These strong intermolecular forces mean that more energy is required to break the bonds between molecules. As a result, it takes a very high temperature (100 C) to reach water's boiling point, or to see the conversion of water from a liquid state to a vapor.
How does glucagon regulate the process of glycogenolysis?
During periods of fasting, glucagon is released from beta-islet cells in the liver. This activates the GPCR signaling pathway in which a G protein and adenylyl cyclase are activated, increasing the concentration of cAMP. cAMP binds to the regulatory subunits of PKA, making the catalytic subunits available. As a result, the activated PKA has 3 roles: 1) It phosphorylates glycogen phosphorylase kinase, activating glycogen phosphorylase in the glycogenolysis pathway. 2) It phosphorylates glycogen synthase, turning it off. This inhibits glycogen synthesis, preventing a futile cycle. 3) It phosphorylates an inhibitor of protein phosphatase I, an enzyme involved in glycogen synthesis. Again, this prevents a futile cycle.
How are polymers built up from monomers?
Monomers can be thought of as the building blocks that link together to make up polymers. This linking process is better known as a dehydration reaction. During the reaction, the 2 reactants each contribute part of what makes up a water molecule. More specifically, 1 molecule donates a hydroxyl group (-OH) while the other donates a hydrogen (-H). Through this loss of a water molecule, the 2 monomers are covalently bonded together. This process is repeated over and over again to form longer chains of monomers, or polymers.
needs and Larisa will reply soon.