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Your reasoning is sound and correct. The answer key is wrong. An unclotted blood sample needs something to prevent clotting. Extracellular calcium is required for both the coagulation cascade and platelet activation. It even has its own name in this context, Factor IV. This why EDTA, a calcium chelator, is used in some blood collection tubes to delay ...


5

Many invertebrates possess myelin. It is a misconception that invertebrates lack myelin. The world speed record for a traveling bioelectric signal is held by the myelinated axons in the abdomen of the Penaeus shrimp! Please take a look at this website or this review to find a highly recommended comprehensive website about invertebrate myelin from about a ...


5

The common scientific belief around 1900 was that the only dietary components needed to support life were protein, fats, carbohydrates, and salts.[1] In 1912 Hopkins reported on experiments showing that "accessory factors" seemed to be needed.[1] In 1916, some of the factors began to be characterized in the paper "The Relation of the Unidentified Dietary ...


4

According to PeaceHealth: The vitamin B-complex refers to all of the known essential water-soluble vitamins except for vitamin C. Vitamin B was once thought to be a single nutrient. Researchers later discovered these extracts contained several vitamins. Each member of the B-complex has a unique structure and performs unique functions in ...


4

Summary Glycolysis and the tricarboxylic acid cycle (TCA cycle) are distinct processes which are not necessarily linked sequentially. It is therefore not surprising that their modes of regulation are not identical and, in fact, involve far more complex regulation than mentioned in the question. The use of AMP rather than ADP as sensor of energy deficit ...


4

The ability of bacteria to take up intact environmental DNA is called natural competence. One problem with trying to take advantage of this in a therapy is that it is not very efficient. Importantly, natural competence is regulated and tends to be activated when bacteria are already stressed. This is also likely part of the answer as to why a bacterium ...


4

It's worth considering how many high energy electrons are actually released compared to the number of molecules in the tube. For instance, I routinely work with $^{32}P$-labeled DNA, and measure the specific activity of samples by scintillation counting. For me, a very hot stock sample of labeled DNA (~1000x more concentrated than I would use in an ...


3

In your second step $(K_d)^n$ should be $(K_A)^n$. Where: $K_d$ is the apparent dissociation constant and $K_{A}$ is the ligand concentration that results in half occupation See for example the relevant wikipedia article.


3

This also lead to the question of whether plasmids can be lethal? Yes, genes in plasmids could be beneficial, neutral or even lethal, although lethal plasmids may have trouble surviving for long since they depend on a live cell for replication. Moreover, if this sort of plasmids exists, then why could we not engineer them specifically and use them as ...


3

Yes. Pork has substantially less heme than beef (Cross et al. 2013). As to why the red colour is lost, it is due to the Maillard reaction, by which the iron in the myglobin is oxidized from Fe(II) to Fe(III). This results in a colour change in the meat (Tamanna & Mahmood 2015). Sources: Cross AJ, Harnly JM, Ferrucci LM, Risch A, Mayne ST, Sinha R. ...


3

This is a hard question to answer because each type of cancer is a whole different game at the molecular level, however there is something you might be interested in called "hallmarks of cancer" (image 1) which are key features for cancer to thrive. They were originally described by Hanahan and Weinberg (2000) and have been revisited by Fouad and Aanei (2017)...


3

As I understand it the question refers to mammalian oxidative degradation of dietary polyunsaturated fatty acids, as the diet is the major source of such fatty acids. Its concern is with two different aspects of this process neither of which involve the use of ATP. The proposition in the final paragraph is therefore incorrect. The first aspect is not ...


2

In vitro studies are often the first studies to check if a certain substance could have a significant effect on a certain structure or function in the human body. In the mentioned study, they tried to support the evidence from earlier studies in which caffeine consumption was associated with skin aging and slow wound healing: Our research confirms our ...


2

A curve of this type, showing a bi- or multi-modal distribution, suggests two or more constituent species in the population. In this case this is borne out by further analysis in the paper of different types of secondary structure components anchoring the loop, the peak at low numbers of amino acids reflecting the loops connecting β-strands in anti-...


1

B doesn't stand for anything. Originally, the vitamins were name alphabetically which can be traced to Cornelia Kennedy's 1916 Master's Thesis. What separates B-vitamins (and all vitamins) is there function. The function of B-vitamins is in metabolism and certain metabolic cycles, such as the Citric Acid Cycle. Citations: http://vc.bridgew.edu/cgi/...


1

One of the advantages of lactose in breast milk is that it is digested slower than sucrose and its ingestion results in lower fluctuations of blood glucose levels thus being a stable source of energy. Lactose, a disaccharide of glucose and galactose, is uniquely present in mammalian milk. Human milk provides the infant with about 40% energy as ...


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