<span><span>anonymous </span> 3 years ago</span>Proteins are involved in almost all of the cell's functions. They can act as:
Transportation: they can transport hydrophobic molecules in blood for example
Regulation: protein hormones and enzymes
Receptor: can act as receptors on cell surface and in the subsequent signal transduction (G-protein for instance)
It is true that all proteins are made up of up to 20 amino acids, but there are several reasons for their diverse actions:
-One reason is the possible sequence and number of amino acids: Met-Ser-His is different from Met-His-Ser for example. Besides, you have different chain length, for a protein is made up of long chain of polypeptide (longer than 50-70 amino acids) and can have any of the 20 amino acids with repetition, so using simple probability, this can provide up to practically unlimited combination with proteins that have chains of thousands of amino acids.
-Another very crucial reason for the diversity of protein action is the conformation. A protein passes by at least 3 conformational stages before becoming mature. The straight amino acid chain is the primary structure of the protein that can never be active. Spatial modification of this primary structure results in a secondary structure, Helix or Beta-pleated sheets (or other coiling structure), that is also inactive. Further coiling and bending of the secondary structure produce a 3-dimentional conformation that is the active form of the protein. Moreover, many proteins can undergo further conformational rearrangement and combination with other protein sub-units producing a quaternary structure.
Answer:
I believe that the best answer to the question: How is it that the same tertiary structure of a protein can result from different primary structures? Would be, B: None of the above.
Explanation:
This is probably the best choice from all the ones in the list simply because due to specific portions of the other answers they make the statement incorrect.
It will help to remember this: proteins have primary, secondary and tertiary structures because when they first emerge from the trascription process from mRNA, they are a simple string where the most important factor is the sequence of aminoacids. It is this sequence which will determine the folding factor. However, there is another factor that must always be kept in mind; environmental factors (temperature, medium where the protein is, as well as location where it is being produced) will also play a role on how the folding will happen and on which of the aminoacids.
The evolvement of a protein chain from its primary, to its secondary and then tertiary shape (the only functional, or known as native state) depends on which of the aminoacids in a specific sequence has the necessary elements to form bonds (hydrogen bonds) with others and thus start the folding process.
Equilibrium.
diffusion occurs due to differences in concentration of substances in different regions. then substances will naturally spread out (due to innate Brownian kinetic energy). the spreading I. e. diffusion will stop until equilibrium is achieved.
note: those substance particles are still moving due to the innate Brownian kinetic energies!
B, metals, nonmentals all bond to be stable
That should be the cell membrane. The cell membrane acts as a filter in and out.
