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6

The situation you ask about was originally part of the 27 ribbon and 2.27 helix structures considered as possibilities by protein chemists (Linus Pauling?) in the 50s or 60s. The diagram below, showing the ribbon, is from the classic text (long out of print) The Structure and Action of Proteins by Dickerson and Geis. This turns out to be very rare in ...


2

Here is a book about dry-matter production of urine treated plants. If we consider that trees are large plants, it's fair to apply the study to trees too: The findings of the study suggested that urine and urine products are equally as effective as mineral fertilizer especially in sandy soil and that splitting the application is a useful strategy to manage ...


3

Parietal cells use ion pumps to expel protons and chlorine ions into the lumen, which create the necessary acidic environment to denature pepsinogen into pepsin. It is the low pH environment that reconfigures or denatures pepsinogen into pepsin. The acid used does not matter. For example, one experiment in classifying properties of pepsinogen used a 3.5 pH ...


3

Scrambled eggs can change color, but you perhaps haven't run into a batch that shows discoloration. It is the same chemical reaction: Why Scrambled Eggs Turn Green When serving a large group, a buffet can provide enough food for everyone without the need to spend all of your time in the kitchen. Breakfast is a fairly simple buffet to set up, but ...


2

That sentence is located in a paragraph titled "Stages 5-7: Endocytosis and recycling": it's talking about recycling exocytosed membrane which is necessary for making vesicles for further exocytosis. The sentences before the part you quoted are: Synapses possess highly efficient mechanisms for retrieving SVs from the plasma membrane of the presynaptic ...


1

I think an easy analogy for why this approach evolves is to think of how humans use electricity (or energy more broadly). Although it is feasible to have localized electricity generators (for example, a solar panel on a simple calculator), it's typically more efficient to have centralized electricity production. With that organization, changes to the ...


1

No, not every protein starts with a methionine. When the methionine is removed, it is called N-terminal methionine excision. Abstract excerpt below: N-terminal methionine excision (NME) is the major proteolytic pathway responsible for the diversity of N-terminal amino acids in proteins. Dedicated NME components have been identified in all ...


0

How can (GPCR) signaling be spatially encoded? Terse explanation: During endocytosis the G protein-coupled receptor can be spatially constrained. Your paper refers to: "Fulfilling the promise of “biased” G protein-coupled receptor agonism", by Luttrell LM, Maudsley S, and Bohn LM, in Mol Pharmacol. 2015;88(3): 579-588. https://doi.org/10.1124/mol.115....


0

I-cells produce the normal functional lysosomal hydrolases, however they are secreted outside of the lysosome. The Hurler cells lack a functional lysosomal hydrolase to degrade the certain oligosaccharides. When the two cell lines are mixed together in the same media, through non-specific endocytosis, the Hurler cells will simply arbitrarily want to ...


0

Yours is a question based on a wrong premise. First, it is very important to note that an amino acid is not made by sticking together 3 nucleotides. However, in the process of translation, the mRNA sequence is read by groups of three nucleotides, named codons. For example, 5'-AAA-3 is a codon that anneals with the 5'-UUU-3' anticodon. So where is this ...


1

In short: base pairs are not composed of amino acids but nucleotides. Base pairs are parts of the DNA, while chains of amino acids forms proteins. Certain parts of the DNA (called genes) are transcribed to messenger RNAs (mRNA) which are sequentially translated to amino acids and the chains become proteins. 3 bases (called a codon) code for 1 amino acid. ...


1

Contractile vacoules are usually surrounded by distinguishing structures The contractile vacuole has several structures attached to it in most cells, such as membrane folds, tubules, water tracts and small vesicles. These structures have been termed the spongiome; the contractile vacuole together with the spongiome is sometimes called the "contractile ...


2

As you guessed, tryptamine alkaloid biosynthesis is generally associated with herbivore deterrence in plants (see e.g. paper 1, paper 2, paper 3), as these compounds can be toxic to animals. I wasn't able to find a reference specifically related to DMT, as it is only one of a family of tryptamine derivatives. For example, the papers just linked to shows that ...


1

When the neuron reaches threshold, this is the trigger that leads to sodium channels opening and this creates a positive feedback process causing the neuron to become less negative and more positive, triggering more sodium channels to open until it is inevitable an action potential will be reached. During an action potential, the neuron cell becomes more ...


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