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6

Each cell will indeed have the same DNA sequences and ability to produce any given protein. However, there are certain factors (transcription factors) and cellular conditions within a cell that dictate which proteins are produced. If the conditions are right then only certain proteins will be produced depending on what type of cell it is. This process by ...


5

There are only 26 letters in the English language, and more than 80% of words are under 10 letters. Yet there are over a million English words. Nonsense words don't count. Now imagine the possibilities of a 20 letter alphabet, where the average "word" length is about 375 letters, and where words of up to 800 letters are possible. And that also does not ...


4

Are there any proteins in the body whose surface is hydrophobic? Sure. Although you are right in thinking that most proteins have hydrophilic surfaces, some are very hydrophobic. My favorite example is Elastin, it is the main component of the skin which grants it elasticity. In fact, the hydrophobic nature of elastin is what confers it its function. ...


3

Yes. The 'order' of amino acids is the protein sequence, also known as the primary structure. A peptide (short protein) with sequence XYXYXYXYX is very different from XXXXXXXYYYYYYY. Your example is a bit trickier, since it seems like AB should be roughly equal to BA. However, each amino acid has two ends - the amino and carboxyl - and so a dipeptide like ...


2

Proteins can move around the membrane. The protein does move: the membrane is a liquid crystal and has fluid behaviour. Specifically this is due to the membrane being in a gel-state. This gel state allows phase behaviour which means that the protein is able to move around on the surface by a similar process. This is often referred to as the fluid mosaic ...


1

Remember that the concentrations you report are in mass units rather than mole units. If the protein has a mass of 40,000 Da, reasonable for many proteins, then 20 mg/liter means $0.5$ x $10^{-6}$ mol/liter. A typical small-mass product of an enzyme reaction might have a mass about 200, so its apparently lower mass concentration of 2 mg/liter is $10$ x ...



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