Tag Info

New answers tagged

1

So, when they subjected "ready to drink" beetroot juice to thermal pasteurization, they found the betacyanin and betaxanthin (our major antioxidants, and pigment molecules) content to be 39.9 and 42.28% degraded, respectively (1). Their conclusion was as follows: Standardization of process condition and quality degradation of beetroot juice due to ...


0

I assume it has an analogous function in ligation buffers. There it apparently takes up a large proportion of the volume and thereby increases the chance of interaction between bits of DNA. In a transformation buffer it should increase the chance of DNA getting into a cell. Unfortunately the only reference I found for this was at Bitesizebio: ...


1

To get to the membrane of these species you first need to get past a formidable cell wall. The methods listed below are therefore more aimed at making cells permeable but the membranes must sustain some damage in the process. At our lab we regularly use glass bead transformation for microalgae transformation. The microabrasion allows DNA to go in so I ...


4

Either the gene is present in multiple copies (especially possible if it is in a plasmid) or multiple RNA polymerases are transcribing it, each beginning from the start site one after the other with some amount of time delay, much like multiple ribosomes translate the same mRNA to increase rate of protein production.


5

Multiple RNA Polymerase transcription complexes engaged on the lacZ gene at the same time, staggered along the gene.


0

For basic knowledge I would recommend the 5th edition of "the cell" and "Lehninger Principles of Biochemistry" 6th edition (3rd and 4th chapter). Even Lippincott's Biochemistry (chapter 2) and Biochemistry by Stryer (6th edition, chapter 2) is good. You can find the 5th edition of Stryer here http://www.ncbi.nlm.nih.gov/books/NBK21154/ If you have access to ...


0

All the information can be found here: http://www.ncbi.nlm.nih.gov/books/NBK21054/ The whole book is there, you simply have to search whichever part interests you or you can also find the paper version in a library. The part on protein structure is Chapter 3. It's a textbook used in some biochemistry and cell biology introductory courses at my university, ...


5

Okay, so for introduction the 4 levels of protein structure (each level influences the levels after it): primary (1st): the order of amino acids. secondary (2nd): alpha-helicies and beta-sheets tertiary (3rd): complex 3d structure quaternary (4th) : 3rd+ non-protein elements (ions, co-factors etc) and / or multple subunits interact. Not every protein has ...


0

Bioluminescence could not be used but it is possible to 'tag' with fluorescence to better view pathways within the body. Tagging is often used in research, a simple google search should produce a plethora of results.


3

Not in human but you can use this technique with genetically modified model organisms as described here. The procedure is quite simple, you express the luciferase enzyme under the control of a specific promoter (specific for your cell type, like cancer) and provide luciferin via intravascular or intraperitoneal injection. The targeted cell type (for example ...


0

In vivo, none. Bioluminescence is cool, but it's not a powerful light source. Even if you could tag a cancer cell (all of them), unless it were on your skin or in your eye, you wouldn't be able to see it, even with some kind of scope.


1

The two main chemical processes in the human body that generate carbon dioxide (CO2) are: Basal metabolic process of CO2 (CO2m) produced by the combustion of sugar in organs and tissues of the body. Bacterial decay processes occurring as a result of activity of the microbial fauna in the colon. This forms CO2 (CO2c), H2, CH4 and higher hydrocarbons, NH3, ...


17

One of the main points of contention in the study of virus evolution is whether or not they appear before the last universal cellular ancestor (LUCA) or afterwards (commonly accepted: genes that "escaped" from host organisms aka the escape hypothesis or vagrancy hypothesis). Basically though, the LUCA is the most recent ancestor that all organisms living on ...


7

Great question. There are several hypotheses, but in reality no one really "knows" because this is incredibly difficult to prove. We may never know for certain. Anyway, on to the three main hypotheses, I got this from http://en.wikipedia.org/wiki/Viral_evolution, I think you'll find it to be helpful. "There are three classical hypotheses on the origins of ...


3

According to Kroeker WD, Kowalski W, Laskowski M. 1976. Mung Bean Nuclease I. Terminally Directed Hydrolysis of Native DNA. Biochemistry 15(20):4463-4467 It was concluded that the products of the terminally directed hydrolysis of native DNA possess 5’-phosphoryl groups because: (1) greater than 99% of acid-soluble activity applied to the column was ...


3

The short answer is that the Edman degradation is a multi-step process. The Wikipedia page has a decent picture of the mechanism. In practice, the peptide is reacted with phenylisothiocyanate (PTH) under mildly basic conditions to give a thiourea, which is stable. The excess PTH is separated from the thiourea intermediate. The thiourea is then treated with ...


0

lacID is an example of a dominant-negative allele (or mutation) so the phenotype is visible in m/+ (the bacterial merodiploids are the prokaryotic version of heterozygotes), and therefore, by definition, dominant, however the phenotype (in this case constitutive expression of the lac operon) is the same as the loss-of-function phenotype (a complete ...


2

Allergies are often caused by the immune system reacting to a part of a specific protein, therefore it is in fact a specific protein in the food that is causing the allergic reaction to occur. Milk allergies are caused by casein and whey (Source: Mayo Clinic) Oat allergies can be caused by avenin (Source: EJCI) Soy and egg allergies are caused by their ...


-1

Manganese(IV)oxide can be used as a catalyst to speed up the decomposition of hydrogen peroxide


2

Concerning the difference between dominant vs. recessive mutations, in general, recessive, or loss-of-function mutations, are much more frequent than dominant, or gain-of-function, mutations, because there are many different ways to "break" or inactivate a protein. For example, not every amino acid site has the potential to mutate to a residue with dominant ...


11

Th reason for this is that for the third base of the tRNA non-Watson-Crick pairing is allowed. This phenomenon is called "Wobble base pairing". See the figure (from here) for illustration (from here): If you have a look at the codon table for amino acids, than the variation in the code for one amino acid mostly happens on the third position (from here): ...


3

Watson-Crick base pairing can be violated by wobble base pairing. The 5' of the anticodon has more freedom in binding, that is why, for many amino acids, the last part of the codon has more possible characters.


4

Short answer. It was discovered pretty early (late 1800's). It is easy to get (you probably know where it comes from), purify, grow and is not virulent. E.coli spreads very rapidly (30 minutes division rate). Why this one in particular and not another similar bacteria? Well you have to choose something at some stage and usually the more an organism is used ...


3

The lac repressor act as a tetramere molecule and requires all 4 of the subunit to be able to bind DNA to act on the operon and repress β-galactosidase expression. The "all 4" is the key here, if any of the 4 subunits is unable to bind DNA then the whole complex cannot attach to the operon. The lacId mutation produces a repressor subunit that cannot attach ...


4

Well there is the common Bloodworm (Glycera dibranchiata)which people use for fishing bait. The animals are unique in that they contain a lot of copper without being poisoned. Their jaws are unusually strong since they too contain the metal in the form of a copper-based chloride biomineral, known as atacamite. ...


1

The change in gel migration distance is due to the conformational changes due to the binding of the ion, and have nothing (detectable) to do with the ionic radius of the ion. The left image shows calmodulin with no ligand bound, and the right image shows it with calcium and peptide bound to it. As you can clearly see, the unbound calmodulin is ...


3

Short answer (A) is a possible answer and is indeed cause for fatigue, as pyruvate is needed for the Krebs cycle to run. The krebs cycle is an essential step in the generation of ATP in aerobic organisms. (B) is incorrect because NADH is never transported into the mitochondria in any organism (it is a nonsense answer). Background NADH is not transported ...


4

According to this study, model data shows a maximum pressure of 110 kPa, that's 16 psi and only 1.086 atm: The three-phase process involved in the beetles explosive secretory discharge (ESD) process. The inlet size is shown as a proportion of the inlet radius. During the first phase of refill and heating (blue), only the inlet valve is open. ...


6

The human skin is indeed made off a number of different layers, the three most important are epidermis, dermis and hypodermis (also called subcutaneous fat), see the figure (from here) for details: All three layers can be subcategorized further, I'll only give a few details here. More can be found for example in the Wikipedia article on skin. Epidermis: ...


3

There are two antipodes: The molecular (or makromolecular) biology, which has the concept of large macromolecules which fulfill one task. This can for example be an enzyme which breaks down its subtrate. The properties and the structure of all molecules of the enzyme are the same and the factor determining the function of the enzyme. The coloidal biology ...



Top 50 recent answers are included