Biochemistry and Molecular Biology

It's agreed that 3500 calories is roughly equal to one pound (i.e. if you eat 3500 calories more than what your body requires, you will gain 1 pound). But 1 gram of pure fat (lard) has 9 calories. 453 grams per pound means that 1 pound of pure fat has 4077 calories. Thus, if you eat 1 pound of lard, you will gain MORE than one pound of weight (about 1.16). This defies what I know about conservation of mass. What am I doing wrong?

Hi people, I need to write a paper on the possibility of life on Mars and If yes why and if no why..........I am out of ideas......can a few genius's help me out please??

We know that our chromosome 2 is actually two fused chromosomes. What kind of phenotypical effect did it have(if any)? Have we experimented with rats or flies to see what it does to them?

i juz beginning to contruct my cDNA library... but after i study the protocol (Stratagene kit), i juz wondering how to calculate the titer of my phage??? if someone know about that, can u elaborate more about this... besides that, i still don't know why i should do the mass excision...

what is a signal anchor in a protein?....

I was trying to do a simple DNA extraction, it went well. Just looked around at some of the cells/junk that were still in the solution. Included was this blue specimin (this was a saline swish around in mouth), I'd guess some kinda bacteria. The measurement shown on the picture, each whole number is .2mm Anyone know what it is? (There was no staining, that's real color)

Took these today under my microscope at 125x. They're a culture of yogurt + milk, for 3 days at about 27*C. Are the circled items bacterium? (All the possible bacteriums, are actually blueish, the camera didn't get the color, and #2 and3 have the shape when overfocused, like http://en.wikipedia.org/wiki/Image:Streptococcus.jpg) http://r0n.kuzew.net:81/img_2224.jpg http://r0n.kuzew.net:81/img_2227.jpg Zooming out of the pics may help clarity since they're very large.

I'm completing a lab report on lactate dehydrogenase and affinity chromatography,after which enzyme activity was assayed for with procion red. I need help explaining the recovery of activity being more than what was applied as well as any possible explanations and investigation.

Hi, Im new to this site, but from what I've read in the threads so far, there seems to be a wealth of useful information shared on the site! I have a problem dispensing an ATP solution, which has confounded me, so any help would be gratefully appreciated! Im dispensing an ATP solution through a nylon filter, but the first few ul that I dispense always has a lower concentration of ATP, then normalises. I thought that the ATP might be binding to the nylon, saturating the filter, but the same pattern of dispense happens for every plate. Any ideas at all??

Hi folks, Can you find out the common relation all the protein quantification methods share?

An enzyme (NAGK) used by a cyanobacterium allows a configuration of arginine units (ammonia storage) that means they don't bind too tightly, so the arginine units remain available:

I am having trouble finding out how to get 10.22 ofr the answere to the following question. Can anyone help? A solution of Valine is obsevered to have its amino group partially deprotonated. 25 % is of the form R-NH3+, and 75% is of the form R-NH2. Assume that Valine has the following pKa values: 2.29 and 9.74. What is the pH of this solution?

Hi, I have a biochemistry question. Throughout glycolysis and the Kreb's cycle, high energy electrons and protons (hydrogens) are removed and used to reduce coenzymes for ATP production in the electron transport chain. The thing that is confusing is that even those hydrogens that are covalently bound to oxygen in hydroxyls seem to get extracted for energy production as well. How can a hydrogen that is already bound to an oxygen provide free energy by eventually being transferred to another oxygen? I know that if you fully oxidize oleic acid (18 carbons, 36 hydrogens) you get approximately 144 ATPs, while if you fully oxidize 3 glucose molecules (also 18 carbo…

Assume that a particular microorganism has 50 distinct t-rna molecules, and that it has 100 copies of each type of t-rna. Further assume that average number of nucleotides in each t-rna is 80. What is the energy cost, expressed as number of phosphoric anhydride bonds destroyed during the synthesis, to synthesize these 100 copies of these 50 different t-rna molecules? This is what I did, I'm not sure it's right: ATP's, 2 per amino acid in the polypeptide (100); GTP's, 1 per initiation event (1) and 3 per subsequent amino acid (150) =251 all together. Do I convert this to kcal/mol? I dunno what to do.

Ok, I have a project to construct my own enzyme. here is the criteria for the model. 1. 100-500 peptides long 2. Must have 2 disulfide links and 1 salt bridge. 3. Must make since in the environment you specify. 4. Must provide (a) protein sequence (b) DNA sequence 5. Must be able to specify and explain DNA change that yeilds a protein change that knocks out your protein. Part (b) of 4 and 5 I don't want to bring up right now. I putting down the criteria, because I'll be refering to it. Note: I don't want you guys to do my project for me, but I think this post will help all understand the Primary, Secondary, and Tertiary Structure of an Enz…

In my study notes it gives a very brief explanation on enzymes regulated by feedback control and it is not making any sense to me. it says... "sequence of reactions whereby the last product D may stop the activity of E1, so that when D is low - the whole reaction is rapid conversely when D is high - the whole reaction is inhibited"

In an attempt to design a treatment for Botulism, you have been asked to design a five-turn alpha-helix that is destined to have half its circuference in the interior of a protein. Draw a helical wheel projection of your prototype alpha-helix using N for nonpolar and P for polar residues. For example, if N1 occupied the 12 o'clock position of the helical wheel, what positions would residues 2,3,4,5,6 etc. occupy and would they be polar or nonpolar? How many residues will there be? After you have drawn your helical wheel, write out the primary sequence of the protein (using N and P) for the five-turn alpha-helix. I know what is a five-turn alpha-helix, but I'm pret…

I have two alcohols that have varying degress of volatility, I assume. I am using them as inhibitors of bacterial growth and in order to do a complete comparison, I need to determine what their actual concentrations are, i.e., what percent stays in solution and which is in gas phase. There are no published Henry's Law constants, thus I was hoping to determine this using only the boiling points. Any suggestions?

Hi there Science Forum ! I was just reading about the levels of protein structure, but was a bit confused what was meant by quaternity structure of a protein, in that if you have a protein sequence i understand that it will form a tertiary structure from that amino acid sequence for sure, but will that same amino acid sequence also make it form a quternity structure (if that protein structure is of that kind ) aswell. I mean take Heamoglobin ive read it has a quaternity structure , did that structure form by the amino acid sequence ? or does every protein form a tertiary structure only and then some how they join with other proteins to form a quaternity str…

Hi everyone, I've had a look on the net before asking but couldn't really find anything. I'm looking for some sites that explain chemical diagrammes...I don't expect anyone to explain it just some good sites would be great. I'm not clear about the lines between the letters and also we some parts of the formula are drawn while other parts are written etc etc Any links would be really appreciated!

Hi... So, this is strange but... I performed an insulin assay (ELISA), which included supernatant from INS1E cells (they are pancreatic beta cells derived from tumor). I dropped the plate after I measured the insulin, it splattered and some liquid splashed into my mouth (I know, ew...but only a tiny drop). Anyway, the MSDS said the chemicals in it can cause minor mucous membrane irriatation, and I didn't even notice that. I was scared because the supernatant was derived from rat tumor...is there any possibility that can transform into cancer?

Dear everyone, I have basic a question about detecting DNA mutations in bacteria. I am investgating whether bacteria (P. aeruginosa) can develop resistance to UVC irradiation . If resistance develops, my hypothesis is that DNA mutation is induced by UVC irradiation. How to prove this? Sorry for this basic question, becuase I am an bioengineer and DNA questions are out of my field. Thank so much!

Hi, I searched some publications but found nothing so I decided to ask you here. Did anybody know if it is effectual for a proper flourescence to transfect one single GFP plasmid into an eukaryotic cell? Is it possible for siRNAs to be be exported out of one cell (wich is transfected with shrna vector) into the medium so that other cells (wich are not transfected) can uptake them, so that they also show target protein silencing? Are there described mechanisms for eukaryotic cells for "spontaneous" sirna/mrna or dna export out of the cell or the uptake of siRNA/mRNA or dna? Hope you can help me.

I am running an assay and wanting to do kinetics. From the literature I am using EDTA as an inhibitor and when I use it I get no pattern of inhibition. I am using 25,50,100 and 150uM concentrations and incubating 40ul of edta with 40ul of enzyme for 30 mins. the absorbance readings do not have a pattern from 25-100 they decrease but the 150 one increases? The isosbestic points do the same. Perhaps I should use more conc EDTA? I have even done the assay in a CaCl2 free buffer and when I add Calcium the absorbance drops even lower. I have no idea whats happening. Any ideas? Thank you in advance for any replies

Does lactose helps stimulate bowel movements to expel waste from the colon?