There are a number of ways that scientists study protein folding and structure. They include the following processes: mutation studies, x-ray crystallography, and spectroscopy. Mutation studies compare the folding patterns of wild type proteins and those with targeted point mutations. X-ray crystallography is a form of high-resolution microscopy that uses x-rays to study the atomic structure of protein crystals through diffraction patterns. Last, a number of spectroscopy methods are employed to study protein folding by comparing unfolded, folded, and partially folded proteins.

Since the interior of cell membranes are made up of the hydrophobic tails of the phospholipids, proteins that are bound in membranes need region that contains high amounts of hydrophobic amino acids residues that can contact the hydrophobic tails molecules and keep it stable. Therefore, in a membrane-bound protein, one would expect the majority hydrophobic amino acid residues to be in the portion of the protein that is buried within the cell membrane.

The formation of beta pleated sheets and alpha helices occur in the secondary structure of a protein immediate after the sequence of the polypeptide has been formed. These two structures, alpha helices and beta-pleated sheets, are formed by the hydrogen bonds that occur among the amino acids of the polypeptide.

The folding of proteins is the second and third level of organization in a protein and determines the protein's shape and how it bonds to substrates. The sequence of amino acids does not determine the shape as much as the folding in the second and third levels. The folding does not determine how long the protein will last in a cell. It does, however, influence the shape of the enzyme, which dictates the types of interactions between the enzyme and substrate, which ultimately determines the rate of the reaction that it catalyzes.

Denaturation is the correct answer here. The denaturation of a protein occurs when a catalyst causes the disruption and/or destruction of the bonds in a protein structure. Heat is one of the ways to denature a protein because the heat causes the molecules to vibrate quickly and coagulate into the white substance we eat.

Secondary structure is made up of alpha helix and beta pleated sheets. Linear sequence of amino acids is found in primary structure, 3D folding is found in tertiary structure, and two peptide chains joined by non covalent bonds are found in quaternary.

When a point mutation results in an inadvertent stop codon, it results in a truncated, and often, nonfunctional protein. This is referred to as a nonsense mutation. A point mutation is caused by a switch of a single base pair in the DNA, which may or may not result in the substitution of an amino acid for another since the genetic code is redundant. 

Histone proteins are highly basic proteins found in the eukaryotic cell nuclei that are integral proteins needed to package DNA tightly inside. They are the chief protein components of chromatin, acting as spools around which the DNA winds and plays an important role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long and difficult to control.