Yggdrasil

In order to get an accurate molecular weight determination of a protein, you generally will not rely on only one technique. Proteins will often run at a different location on the gel than predicted for various reasons, so molecular weight calculation from SDS-PAGE can often be misleading. However, in addition to SDS-PAGE which measures the molecular weight of the denatured protein, techniques such as analytical gel filtration or analytical ultracentrifugation are used to measure the molecular mass of your protein in its native state, and can provide independent confirmation of the molecular mass determined using SDS-PAGE. However, if you just need a quick confirmation that your protein is of the correct size, SDS-PAGE provides a reasonable estimate of molecular weight.

The second law of thermodynamics does not state that [math]\Delta S_{sys} > 0[/math], it states that [math]\Delta S_{tot} = \Delta S_{sys} + \Delta S_{surr} > 0[/math]. So, for photosynthesis while the entropy of the system decreases, the corresponding increase in entropy of the surroundings (e.g. from heat created during photosynthesis and the breakdown of water to oxygen gas and protons) will make the overall change in entropy positive.

In order to PCR amplify your putative iron reducing gene, you need to figure out the sequence flanking the gene in the E. coli genome. Using that sequence information, you can design sequences completmentary to the region upstream of the gene on the antisense strand and complementary to the downstream region of the sense strand. In general, PCR primers must be designed by the researcher and are not found by searching on the internet.

If by Bragg relflections, you mean Bragg diffraction, I don't think that's relevant since SPR isn't used to calculate distances. SPR is used to measure the index of refraction of a layer of biological molecules, which is proportional to the mass of the molecules in that layer.

In biochemistry, we use devices which use the principle of surface plasmon resonance to study the binding between biological molecules. Even though I uses these machines, I'm still not to clear on how exactly they work. All I know that shining monochromatic, plane polarized light on a thin metal boundary between two materials with different indices of refraction generates a "evanescent wave" which will reduce the intensity of the totally internally reflected light at a specific angle, but I'm not exactly sure what the "evanescent wave" people talk about is nor why it reduces the intensity of the reflected light at a specific angle. Any clarification on these issues would be appreciated.

There is also the problem that evolution and natural selection act on a fairly large time scale. Given that cars have only been available for the public for about eighty years (~4 human generations) and that our fossil fuel supply will run out sometime within the next 50-100 years (which will drastically change the way our society operates, hopefully eliminating the concept of the private motor vehicle for more widespread mass transit), I doubt cars will be around for enough time to exert enought of a selective pressure to affect the human gene pool.

I checked my biochem notes and I have written down that in a healthy liver cell, the concentrations are: [ATP] = 5mM [ADP] = 1mM [AMP] = 0.2mM The prof. didn't give a source, so I'm not sure how accurate the numbers are, but I would expect the ratio to be somewhere around 5-10. The other NTP/NDP ratios should be similar because of nucleoside diphosphate kinase.

In the presence of acid catalyst, 1-butanol would form primarily (E)-2-butene. The acid catalyst would promote the formation of a primary carbocation through an E1 mechanism, which would then undergo an intramolecular rearrangement to a secondary carbocation. The secondary carbocation would then preferentially form the internal, trans alkene, although minor amounts of the terminal alkene (1-butene) and the cis alkene ((Z)-2-butene) would be formed. A biochemist would refer to the second structure as glycerol, although insane_alien's names are more common among organic chemists.

What kind of life science course? General, genetics, molecular biology, biochemistry, cell biology, ecology, etc. all would have different texts.

Exactly how newts and other urodele amphibians are able to dedifferentiate cells is an active area of research, and scientists do not yet have a clear idea of the mechanism of regeneration. However, I did read over some reviews on the subject and apparently, scientists believe that some of the homeobox proteins, which play a critical role the differentiation of cells, may also play a role in the dedifferentiation of cells.

What would be the point of producing ATP? Wouldn't it be more efficient to use the electrical energy from the fuel cell directly, since there will be energy lost when producing the ATP and energy lost when converting the chemical energy stored in ATP to mechanical energy?

A lot of detergents/surfactants, such as sodium dodecyl sulfate and octyl glucoside, are used to simulate phospholipids in biochemical experiments.

For #3 try thinking about surface area-to-volume ratios.

http://structbio.vanderbilt.edu/chazin/wisdom/labpro/sterile.html Here's the first page from google that pops up from a search on sterile technique. In addition to working with a bunsen burner flame, I would also recommend wiping your bench with isopropanol (rubbing alcohol) before working with the bacteria, and working in an area that isn't close to any ventilation ducts which may increase the flow of dust particles around your bench area.

I was looking into the increased sensory perception issue and it might be due to norepinephrine, which is released by the adrenal medula in addition to epinephrine during the "fight-or-flight" response. Aparently, drugs which inhibit the reuptake of norephinephrine (e.g. atomoxetine) are used in the treatment of ADHD.

Epinephrine (aka adrenaline) has numerous effects on the body, which are collectively termed the "fight-or-flight response." In the liver, epinephrine activates the breakdown of glycogen stores, releasing glucose into the bloodstream. In addition, it mobilizes fat stores from adipose tissues. These two effect make more energy available for muscle tissue. Furthermore, epinephrine increases heart rate and dialates/contracts selected blood vessesls to redirect blood flow toward muscle tissue and away from systems which are not needed during fighting of fleeing (e.g. the digestive system). So, these actions do prime the body for extreme physical activity, so it will allow you to run faster and jump higher than under other conditions. I'm not sure about epinephrine affects sensory neurons, so I can't tell you how or if epinephrine makes your senses more accute. Perhaps it is the result of increased blood flow to the brain.

However, unless you know and practice proper sterile technique, it's also amazingly easy to grow other contaminants along with your bacteria.

http://www.nature.com/news/2005/051219/full/051219-17.html

Probably not. An autoclave heats liquid media to about 120 C in a pressurized chamber, which prevents the liquid from boiling. You may be able to make fairly sterile media by bringing your meda to a boil for a few minutes, covering your flask with some foil, and cooling it to ~ 40 C in a hot water bath before pouring your plates. Also it would help to disinfect down any benchtops you're going to use with 70% ethanol or isopropanol (rubbing alcohol) beforehand.

In general, mold looks kind of fuzzy. Bacteria should give you nice, round yellowish dots. After overnight growth on complete media, bacterial colonies generally don't get more than a few mm in diameter.

Most of the time, the color of complex ions comes from d->d transitions. That is, the absorbtion of a specific wavelenght of light excites electrons in one d orbital (e.g. from the t2g orbitals to the eg* orbitals). Calcium, potassium, and sodium are all in the first two columns of the periodic table and therefore, their valence electrons are only in the s orbital. Transition metals like cobalt, iron, and manganese have d electrons and therefore can have d->d transitions. It is also worth noting that despite the fact that zinc is a transition metal, Zn2+ ions are generally colorless because they have a full d subshell, so no d->d transitions can occur.

The problem with such a method is that as far as I know, there is no protease which cleaves gp120 in the membrane. As opposed to CoQ, insulin, and other enzymes/proteins produced by biotech companies, there is no gene (template) from which bacteria or other organisms can express the protein. Therefore, one would have to design a novel enzyme from scratch, not an easy task. This has been done by the Hellinga group at Duke, but they designed the enzyme based off of the structure of an already existing enzyme (triosephosphate isomerase). Designing a novel protease for gp120 may be within our capabilities, however, since we do know how many proteases work. The main challenge would be to make the enzyme specific for gp120 in HIV envelope as well as making it stable in the extracellular environment (perhaps something like a catalytic antibody would be suitable as well).

I believe the problem you are having is that you are using polyhydroxylated substrates for your reactions. Since oxidation of an alcohol to a ketone or acid is exothermic, oxidizing a compound with multiple OH groups can produce a lot of heat, which will lead to overoxidation and thermal decomposition of most of your product. So, the solution would be to either use a weaker reducing agent or try oxidizing other substrates. If you're interested in oxidizing sugars, you can oxidize glucose (or other aldoses or 2-ketoses) to an aldonic acid in basic conditions by treatment with Br2/CaCO3/H2O, Ag2O or tollen's reagent (Ag(NH3)2+). These reagents will convert the aldehyde of an aldose to a carboxylic acid. It works to some extent on 2-ketoses (e.g. fructose) since they isomerize to aldoses in basic conditions. Unfortunately, sucrose (table sugar) is not a reducing sugar, so it cannot be oxidized to an aldonic acid. Periodic acid can also be used to oxidize sugars.