Biochemistry and Molecular Biology

Hi everyone! new to the boards! just have a quick question I've seen examples of irreversable enzyme inhibitors causing down-regulation of gene expression of certain genes which causes problems with production of that enzyme once the enzyme inhibitor ceases to be in the system. My question, is there any articles which are examples of this that you can think of off the top of your head? I need to find sources for a paper I am writing.

How does fat change to glucose? Please give links, slideshows and e-books, where are reactions, schemes, mechanisms and other useful information. Thank you!

Hello all, I am quite new to molecular biology! I recently sequenced a number of mitochondrial genomes and found a number of sequence variants. I want to do a homology search online to see if the sequence variants I have found are evolutionarilly conserved or not. I am a bit lost where to start , Any ideas?

Can any one give me a stereochemical structure of L-Cysteine by using the Fischer convention and indicate whether it is the R or S configuration? Please!! I've searched every website for two days and no detail the L-Cysteine (well the things that I wanted).

good evening, actually I need some help by calculating the pka and pkb value because I don't know how to calculate it. so please instruct me how to calculate it. miya

Hi everybody, actually I'm a new member in the forum and I need your help I want you to teach me how to use the spectrophotomter because I have an examination next week and thank you

This is my first post here, so hello everyone. Making my foray into the wonderful world of science via an Access course (read A-level for mature students) in Marine and Environmental Science. See you at the lab in a few years' time. Anyway, onto the question. Working away on a biochemistry module at the moment (RH5/3/WW/003). Trying to rationalise to myself the formation of sucrose from glucose and fructose, as you may have determined from the thread title. I found this website: http://dl.clackamas.edu/ch106-07/sucrose.htm What I don't understand is their explantion of how b-D-fructose in standard orientation, shown here: ...gets flipped to b-D-fruc…

Hai everyone, im new to this forum and i am really confuse and curious about this. In cellular respiration, there are three process, glycolysis, kerbs cycle and electron transport chain. Kerbs cycle and electron transport chain cant proceed without the presence of oxygen. So the only possibilities on how the energy is produced during anaerobic respiration is through glycolysis. The output of glycolysis is 2 pyruvic acid, 2NADH, 2H20 and 2ATP. The thing that doubt me is that pyruvic acid must undergo fermentation to form lactic acid. But the thing is one of the output of glycolysis is NADH not NADH2. Whereas the equation shows that 2C3H4O3 + NADH2 --> 2C3H6O3 + NAD + 2…

I purchased fluorescent labeled RNA. And I want to detect the RNA concentration using 260nm reading. But I need subtract the fluorophore effect at 260 nm using equation A260corre=A260-(Amax*C.F.260), where i can find the C.F.260 for different fluorophores? Especially TAMRA and ROX? Thanks a lot

I am having a hard time understanding how to interpret electrophoresis gels. I have spent a lot of time looking into this and need some help. Why do double digests sometime create one fragment on the gel? I thought that there should be more fragments since the DNA is being cut twice?!

Pasteur effect states that the presence of oxygen would suppress the glycolytic rate. Modern interpretation is that oxygen allows procession of Krebs cycle and electron transport chain, generating an amount of ATP far exceeding that from glycolysis alone. ATP in turns suppresses a rate-controlling enzyme in glycolysis of phosphofructose kinase 1 allosterically. I was given a graph showing periodic relationship between ATP and NADH, which is a product of glycolysis and serves as an indicator of the procession of glycolysis. The graph shows an exactly out-of-phase relationship. However, I think that, according to the mechanism suggested, the kinase has to be given a per…

If any of these seem wrong, please do tell me with an explanation. I am still really confused with this all, so I had to guess on a lot of them. The help is greatly appreciated! Thanks! 1. For an amino acid residue in Hb to act as a proton binding site in the Bohr effect, a) it needs to have a pKa value that is within the blood pH range and the pKa value must change between deoxy and oxy states b) it must be negative in charge c) it must have a pKa value that is above 9 d) all of the above e) “b” and “c” 2. The peptide sequence ALEPTWFEHDKFVADKFVA : a) could not form an alpha-helix b) could form an alpha-helix c) could partially form an alpha…

Hello, I am trying to overexpress my protein of interest using standard recombinant bacterial expression techniques of batch fermentation in shaker flasks. I have had this problem twice in the past 3 years, where a prep will appear to grow very slowly, then will suddenly flourish 24-48 hours after it is started. The media will turn a yellowish color and smell very strongly of buttered popcorn, and the resulting cell pellet will be much darker in color than the usual E. coli pellet. Oh yeah, and I'll get no protein out of my prep. I'm curious whether anyone knows what common bacteria/fungus/yeast/whatever could possibly get into a culture containing antibiotics …

My biology teacher mentioned in class that chemical signals(hormones) are connected to the amount of glucose in the bloodstream? When I asked him to elaborate he refused and said its not for high school.... . Anyways I tried researching on the subject, but no find. Do you guys have any clue how the two can be connected? I thought about Insulin (hormone) in respect to glucose, but i don't know. But is that really the only hormone correlated with glucose. there must be others?

hi. I need data for immunodominant CTL epitopes. there are several definitions for "immunodominance". some studies refer all epitope that induce response as immunodominant. however, more correct immunodominance definition is the competition in inducing response between several epitopes expressed on the same cell at the same time. this kind of data is very rare. do you have any idea? thanks/

...per minute? In terms of the Krebs Cycle, why do we on average exhale 12 times. I am utterly confused at the question my teacher has asked us in class....

Would it be possible to heat cold running water without using gas or electric sources fast and to a high temp? I want to heat cold water coming down a conventional hosepipe from the very 1st drop BUT the heating process would need to be done in the last 10cm or so. Has anyone got any ideas on how this could be achieved?

From which organ is this enzyme secreted from??? He is an aspartic protease enzyme??? With which order from the brain??? Lutesium...

Hello Everyone: I'm a fairly well educated guy currently in graduate school, but what I am studying probably could be considered the polar opposite of biochemistry. My question is about the endogenous opioid system and long term methadone treatment (MMT). I've been trying to read some journal articles that look into either one topic (eos) or the other (MMT), but I have yet to find one that really contains the answers I am looking for, not to mention that with most articles, I have to constantly look up terms I don't understand. My general knowledge about biology, chemistry, and these topics in particular is more extensive than most laypeople, but I'm definitel…

Hi, I was wondering if there is a link between the hyperphosphorylation of tau protein and amyloid plaques in alzeihmer's disease? Are both present in Alzeihmer's?

Although they're are very inexpensive to make from scratch as needed, I'd like to have a small storage of agarose gels for experiments (e.g. checking clone inserts, plasmid sizes, usual stuff). What's the best method to store them? I usually make 1% agarose gels with ethidium bromide. How long do they stay fresh, without impairing the quality of the results?

How is the paratope of an antibody formed?

If there are billions of neurons that might be the one the axon needs to connect to, does this mean that there are billions of different signal cues? And if so, how is this diversity achieved? How about negative signal cues? Where do those come from?

If I have a partition function say p = 1 + Kx where K is some constant describing a simple ligand binding to a macromolecule and x is the concetration of the ligand. What is the significance of taking the derivative of this function such that you take the natural log of the function and take the derivative with resepect to the natural log of x, so dln(p)/dln(x). This give me X which is the average ligation of the system (i.e. 0.5 or 0.2 of the macromolecules have a ligand bound). Where do these natural logs come from? Anyone have an idea what thats all about?

How did the mtDNA haplogroups arise? I understand vey well how did Y-DNA ones appear: you have one sperm cell, with one Y chromosome, with one mutation, and this mutation will be in all the cells of the new individual, and he will inherit it to all his offspring. Over the centuries many different mutations in many different lineages result in many different Y chromosome varieties. However this is not so simple with mtDNA, because an egg cell does not have just one mitochondrion (how many by the way?) but many, and if one mitochondrion replicates and one mutation arises in the process, its DNA still will be a small percentage of the total mtDNA of the cell, and of the to…