Building the Chain: Peptide Bond Formation

If the ribosome is assembling a protein, then it must link individual building blocks. If the specific chemical link between these amino acids is the peptide bond, then this process is referred to as peptide bond formation.

If an enzyme is required to speed up the chemical reaction between amino acids, then a catalytic center must exist. If the large ribosomal subunit uses its ribosomal RNA to facilitate this bond, then the ribozyme known as peptidyl transferase is responsible for peptide bond formation.

If resonance occurs between the oxygen of the carbonyl group and the nitrogen of the amino group, then the electrons are shared. If this sharing creates a bond that is stronger and less flexible than a single bond, then the peptide bond formation results in a rigid, planar structure.

If a dehydration reaction builds a bond by removing water, then adding water back should break the bond. If digestive enzymes use water to split proteins back into individual amino acids, then hydrolysis is the correct term for the opposite of peptide bond formation.

If the prefix "di-" means two, then it describes a structure with two units. If two amino acids have been linked by one peptide bond, then the resulting molecule is logically called a dipeptide.

If a bond is formed by the sharing of electrons and the removal of atoms (water), then it is a permanent, strong link. If non-covalent attractions (like hydrogen bonds) are easily broken and do not involve sharing electrons, then the peptide bond is covalent, making the statement false.

If an amino acid must lose an H or an OH to form a bond, then it is no longer a complete, independent amino acid. If what "remains" of the amino acid is now part of a chain, then it is scientifically called an amino acid residue.

If the amino group acts as a nucleophile, then it must attack the electrophilic carbon of the carboxyl group. If the nitrogen has a lone pair available for this attack, then the statement accurately describes the first step in the mechanism of peptide bond formation.

If all proteins (enzymes, muscles, transport channels) are made of amino acids linked together, then the link is essential. If the peptide bond is the only way to join these amino acids, then a failure in peptide bond formation means the cell cannot build any proteins and will die.

If two monomers are joined together by removing a molecule of water, then the process is called dehydration synthesis. If the carboxyl group of one amino acid loses an -OH and the amino group of the next loses an -H to form a link, then peptide bond formation is a dehydration reaction.

If the R-groups are responsible for the unique properties and folding of a protein, then they must remain free to interact. If the peptide bond provides the backbone of the protein, then it must form between the central carboxyl and amino groups instead, making the statement false.

If a peptide bond links the "C-terminus" of one unit to the "N-terminus" of the next, then those specific groups must be the reactants. If the carboxyl group (COOH) and the amino group (NH2) provide the necessary atoms to form water and a C-N bond, then they are the correct groups.

If a new amino acid is always added to the carboxyl end of the existing chain, then the starting end (amino end) remains free. If the sequence begins at the amino group and ends at the newest carboxyl group, then the direction of peptide bond formation is N-terminus to C-terminus.

If a dehydration synthesis reaction removes an oxygen and two hydrogens to link two molecules, then those atoms must form a new stable molecule. If O and H2 combine, then water (H2O) is the logical byproduct of peptide bond formation.

If the ribosome moves along the mRNA and facilitates the docking of tRNA, then it requires a high-energy source. If the translation machinery specifically utilizes guanosine triphosphate to drive the elongation of the polypeptide, then GTP hydrolysis powers the peptide bond formation.

If the primary structure is defined as the linear sequence of amino acids, then the bonds connecting them determine this level. If these bonds create the repeating C-C-N chain of the protein, then peptide bond formation establishes both the primary structure and the polypeptide backbone.

If the ribosome must hold the existing chain while a new amino acid arrives, then it uses specific internal sites. If the bond is formed as the chain is transferred from the tRNA in the P-site to the tRNA in the A-site, then that is the location of peptide bond formation.

If a ribosome continues to add amino acids one after another, then a long polymer is created. If this polymer consists of many ("poly") peptides linked together, then the result of consistent peptide bond formation is a polypeptide chain.

If the reaction requires an input of energy (GTP), it is endergonic. If it releases water, it is a condensation reaction. If the ribosome's RNA acts as the catalyst, it is ribozyme-mediated. It does not occur in the nucleus and does not form phosphodiester bonds (which are in DNA).

If the body needs to recycle proteins into amino acids, then it must have specific enzymes to target peptide bonds. If "prote-" refers to protein and "-ase" refers to an enzyme, then proteases are the biological tools that undo peptide bond formation.