Session Start: Tue Sep 30 18:18:15 2008 Session Ident: #Chemistry [18:18] * Now talking in #Chemistry [18:18] * fred has quit IRC (Quit: Leaving) [18:18] * fred has joined #Chemistry [18:18] * fred has quit IRC (Quit: Leaving) [18:19] * Disconnected Session Close: Tue Sep 30 18:19:02 2008 Session Start: Tue Oct 07 12:59:23 2008 Session Ident: #Chemistry [12:59] * Now talking in #Chemistry [12:59] * chemistry.gravitywaves.com sets mode: +nt [13:12] * guesar14 has joined #Chemistry [13:12] anyone here? [13:12] * guesar14 has quit IRC (Quit: Leaving) [14:16] * tuscani has joined #Chemistry [14:16] * tuscani has quit IRC (Quit: Leaving) [16:00] * DrSturm has joined #Chemistry [16:55] * Electron has joined #Chemistry [16:55] * Electron has quit IRC (Quit: Leaving) [16:59] * Hb has joined #Chemistry [16:59] Hi Dr. Sturm [17:00] Can you explain why the Michaelis-Menten Equation is importnat? Is it because it measures the affinity of enzymes to substrate? [17:01] It describes enzyme kinetics [17:02] why does it have to be inverted? to make it a linear equation? [17:03] Inverting it turns it into an equation for a line so it can be shown graphically [17:03] oh ok [17:04] can you give me the definition of a heavy chain and light chain? I know where they are on the antibody and I know that in the Fab region, they form the binding site for antigens, but I dont know their formal definitions [17:05] They are proteins. [17:07] what about haptens? [17:08] A hapten is a small molecule which can elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one which also does not elicit an immune response by itself. [17:10] so it's not on the antibody itself? so it's just in the blood as a single entity until an immune response is needed, in which case it would then attach to a protein to elicit the response [17:10] is that correct? [17:11] No it is an antigen [17:11] oh [17:12] so when the antigen (of a foreign material for example) binds to antibodies in our body, then the immune system responds [17:13] ok, I get it [17:13] When a foreign invader is detected Ab's are produced to detroy it [17:14] I thought Abs only flag down the foreign invader so that macrophages can destroy it [17:15] Ab's remove foreing bodies [17:17] macrophages originate from white blood cells but are a bit more specific [17:18] For instance: One important role of the macrophage is the removal of necrotic cellular debris in the lungs [17:18] don't they need some kind of signal to know what material to destroy and which ones to leave alone? [17:20] Macrophages are foremost among the cells that "present" antigen; a crucial role in initiating an immune response. [17:22] ok [17:23] the combination of the seven CDRs on the antibody is what gives the Ab it's vast diversity? [17:24] Well within on Ab there are two identical binding sites, for there are a lot of different Ab's which vary one from another in the hypervariable region (CDR's) [17:25] oh ok. [17:26] just out of curiosity, how long can an antibody last in our body after it has been made? [17:26] like, can we still fight off the flu from last year if we got the flu shot last year? [17:28] I think it depends on the specific Ab, certainly most vaccines last a lifetime [17:28] interesting. [17:30] the Fc region of an antibody is used to distinguish one class of immunoglobulin from another, does it do anythign else? [17:30] Not really [17:33] Proton, CO2, and BPG all decrease affinity of Hb for o2 in the tissue by forming salt bridges which stabilizes T state, while in the Lungs, all three increase affinity? [17:33] Is that correct? [17:33] Yes. [17:33] * Phospho has joined #Chemistry [17:34] * Phospho has quit IRC (Quit: Leaving) [17:35] we want low affinity of fetal hemoglobin for BPG because this would allow for a higher affinity for O2, which is good for the fetus correct? [17:36] Yes. [17:37] how come the graph for the Exergonic reaction has two "humps" while the Endergonic graph only has one? [17:39] Either could have two peaks just depends on the specific reaction being shown. [17:39] oh ok [17:41] in lecture the other day, when you were talking about fevers, you said that when a fever develops, the rate of all metabolic pathways will increase, which means the body will need for energy...which is why it's ok to consume food high in fat and cholesterol? [17:41] I wasn't sure if I heard it right [17:46] Never really good to consume high fat food, you do need increased calories but it would be better if they were from proteins and CHO's [17:47] so being sick is not an excuse to eat fatty foods huh? darn. [17:48] Unfortunately no. [17:48] can you describe the different forces involved in the binding of an antibody to its antigen [17:49] ionic interactions, salt bridges, hydrophobic and hydrophilic attractions [17:50] is there a difference between cleaving a substrate and lysis of a substrate? [17:50] lysis means cleaving [17:50] oh ok [17:53] last question, velocity has to do with the rate at which the enzyme binds to the substrate and makes it into a product correct? Then why isn't Vmax defined as the velocity at which the enzyme is makes the most product. why is it defined as when all the enzymes contain a substrate? [17:54] does binding of a substrate to an enzyme neccesarily means that a product will be made? or can the enzyme release the substrate before it is turned into a product? [17:58] An enzyme binding substrate ensures there will be product. [17:59] oh ok. Thank you Dr. Sturm, see you tomorrow. [18:02] * DrSturm has quit IRC [18:02] * Disconnected Session Close: Tue Oct 07 18:02:10 2008