Trypsin will cleave the primary sequence after the lysine residue (on its carboxyl side). Thus, Lys will be the new carboxyl terminal and Glu will be the new amino terminal. Remember that a protein's primary sequence is written from N to C.

Ubiquinone functions to carry electrons in oxidative phosphorylation from the first enzyme complex to the second enzyme complex. It does not receive electrons from nor directly.

With the excess buildup of protons in the matrix, the only thing that will be inhibited is the generation of ATP by ATP synthase. The other processes in cellular respiration focus more on creation of high energy electron carriers, and therefore will continue as normal.

Charged molecules do not permeate the lipid bilayer easily at all. So despite its small size, among our choices, a sodium ion passes least easily through. Polar molecules also have a hard (but less difficult) time passing through, and the larger the molecule, the harder that becomes, so after the sodium ion comes glucose, followed by water, which is polar but much smaller. Small, hydrophobic molecules -- such as carbon dioxide -- diffuse through most easily, because they can pass through the longest (hydrophobic) part of the membrane.

Although it is one of the three main types of membrane lipids (along with phospholipids and glycolipids) cholesterol's structure is quite different. It is a steroid, and so it is made from four linked hydrocarbon rings, including three six-membered rings and one five-membered ring.

The electron transport system is the only metabolic process listed that directly requires molecular oxygen. Oxygen is the final electron acceptor (it is one of the most electronegative atoms in our bodies) in the electron transport chain. This is the same as saying that oxygen has the highest reduction potential, and is capable of receiving electons. If oxygen is not present to accept the electron from the final enzyme complex in the inner mitochondrial membrane, then electron transport will be inhibited and thus no ATP will be produced via chemiosmosis.

Note that the Krebs cycle, citric acid cycle, and tricarboxylic acid cycle (TCA cycle) all refer to the same process, and do not directly require oxygen (oxygen is neither a reactant nor a product in any of the steps). However, oxygen is indirectly required, as there is no point to this cycle without subsequent oxidative phosphorylation. Thus in the absence of oxygen, of the choices shown, only glycolysis will proceed uninhibited.

With the excess buildup of protons in the matrix, the only thing that will be inhibited is the generation of ATP by ATP synthase. The other processes in cellular respiration focus more on creation of high energy electron carriers, and therefore will continue as normal.

Primary structure: linear sequence of amino acids

Secondary structure: hydrogen bonds, alpha-helices and beta-pleated sheets

Tertiary structure: disulfide bonds, single polypeptide chain

Myoglobin is a monomer, and is made of a single polypeptide chain. Thus, its highest level of protein structure is tertiary. While collagen does contain different polypeptide chains, it is an example of a protein with quaternary structure, not an explanation of what this means.

Cholesterol is made up of multiple rings, including three six-carbon rings and one five-carbon ring. This characteristic structure is also seen in steroid hormones and metabolites, as many biologically relevant molecules are derived from cholesterol. Fatty acids are long hydrocarbons (typically between ten and thirty carbons long) with carboxylic acid functional groups on one end. Glycolipids are lipids that have carbohydrate moieties attached, which play a role in cellular and molecular communication. Sphingolipids are a class of lipids that contain a sphingoid base backbone and include sphingosine, sphingomyelin, ceramides, gangliosides and others.

Alpha-linolenic acid is an essential fatty acid that must be consumed in the diet (cannot be synthesized by the body). It is an eighteen-carbon omega-3 fatty acid that is used to synthesize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two important long chain polyunsaturated fatty acids. Alpha-linoleic acid is the precursor to arachodonic acid (AA).