The three-dimensional structure of macromolecules is formed and maintained primarily through noncovalent interactions. Which one of the following is not considered a noncovalent interaction? Group of answer choices 1. carbon-carbon bonds 2. hydrogen bonds 3. hydrophobic interactions 4. ionic interactions 5. van der Waals interactions

The correct option is 1. carbon-carbon bonds

Explanation:

It is called covalent bonding to a type of chemical bond, which occurs when two atoms bond to form a molecule, sharing electrons belonging to its most superficial layer, thereby reaching the well-known "stable octet". Carbon-carbon bonds are covalent bonds, which take place between two carbon atoms. There are simple bonds, which are generally the most common, since it is formed by two electrons, each one of one of the atoms participating in the bond.

The rest of the options belong to the groups of non-covalent interactions, these do not share electrons.

The ionic interactions and forces of Van der Waals interactions are purely electrostatic in nature (attraction or repulsion of electric charges), although neutral molecules participate in the latter, interacting well with other neutral molecules or with ions. The hydrogen bond or hydrogen bridge also has an electrostatic nature, but simultaneously has a certain covalent character. Finally, hydrophobic interactions depend on the high degree of water disorder, (that is, on its high entropy) and are characteristic of those molecules that cannot easily interact with water.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.