What is a peptide bond?
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"The chemical bond formed between the carboxyl groups and amino groups of neighboring amino acids, constituting the primary linkage of all protein structures."
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There isn't one standard answer to this question.\nThe most common definition of a molecule is the smallest unit of a material that retains it's chemical attributes.\nmolecules interact with each other by electrostatic (electric) interaction :\n1. charged molecules interact by repulsion or attraction of monopoles.\n2. A charged and uncharged molecule interact by monopole-dipole interaction\n3. 2 uncharged molecules that have a permanent dipole interact by dipole/dipole interaction. A special case of this is hydrogen bonds between two hydrogen bearing molecules.\n3. molecules that do not posses dipoles interact by induced dipole/induced dipole interactions. An example of this is the formation of a solid from Argon atoms (molecules).
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Sigma Bond:\n     A type of bond between two atoms in which two partially filled atomic orbitals overlap in such a way that the probability of finding an electron is maximum around the line joining the two nuclei.\n                           OR\n     Sigma bonds are those bonds between atoms in a molecule that exhibit orbital hybridization\nPi Bond:\n     A type of bond which is formed by the sideways overlap of two half filled co-planar p-orbitals in such a way that the probability of find finding an electron is maximum perpendicular to the line joining the two nuclei.\n                          OR\n    Pi bonds are those bonds between two atoms in a molecule that do not exhibit orbital hybridization
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Denaturation usually occurs with boiling or mild reaction conditions; a, c, and d will alll occur. These are all relatively weak bonds. However amino acid sequence will remain, you need harsh conditions to break these strong peptide bonds.\nb) is answer
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codons  are molecules  that are part of messenger  rna  that represent a part of a protein to be synthesized.\nthe anticodon is part of the ribosome  that fits with the codon like 2 pieces of a jigsaw puzzle would fit and it will result in the attachement of a particular amino acid\nthus fro attaching different amino acid sequences different proeins are made for different dna sequences.
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In chemistry, bond dissociation is a process in which a specific bond is cleaved by homolysis. Bond dissociation is an endothermic process, and energy that is necessary to the process is called bond dissociation energy. Note that following dissociation, if new bonds are formed at lower enthalpy, then there is a net loss of energy, and thus an overall exothermic process.
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Ionic bond, hydrogen bonds, covalent bond, ionic interactions, van der waals interaction, non-polar interaction ... the list goes on.\n\nA bit more on covalent bonds:\nThere are sigma and pi covalent bonds, mainly. Pi bonds are usually the double bonds, while sigma are single bonds. Pi bonds can have resonance!\n.\nAlso there are often non-bonding electrons and anti-bonding electrons in molecules, but they aren't really "bonds"\n.\nCheers.\n.\nP.S.: If you share "chemistry" with a girl / boy you could also call that a "chemical bond"! He he he he.
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There is a very informtive article about peptides at the following link. It includes the following about peptides:\n\n1 Peptides in Molecular Biology \n2 Peptide families \n2.1 Vasopressin and oxytocin \n2.2 The Tachykinin peptides \n2.3 Vasoactive intestinal peptides \n2.4 Pancreatic polypeptide-related peptides \n2.5 Opioid peptides \n2.6 Calcitonin peptides \n3 Notes on terminology \n4 External links \n5 See also
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The function of a protein depends on its shape.  If you alter the shape of it, you alter its function.  pH is a factor that can alter the shape, because the pKa values of residues on the protein will dictate which residues are or are not protonated, and that will, in turn, affect the manner in which the various amino acids will form internal ionic bonds.\n\nTemperature is another factor.  the stability of intramolecular bonding is dependent on the level of thermal excitation.  If a protein is at a high temperature, the thermal motion of the atoms might upset their abilities to form bonds.  At really high heat, the result will be total denaturation.  At low temperatures, you might even have the opposite problem, with a protein clinging to things in the wrong ways.\n\nFinally, you might alter it by introducing a chemical that reacts with it.  Some proteins need activator molecules to function, others might be inactivated by an inhibitor.  Enzymatic activity occurs in what is called the "active site" of the protein, which is where the substrates bind to the protein and catalysis occurs.  So the activity of the molecule might be altered by changing the arrangement of the moieties in the acive site relative to one another, of there might be a change which permits/blocks access to the active site by the substrate molecules.
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Amino acids are the basic structural building units of proteins. They form short polymer chains called peptides or polypeptides which in turn form structures called proteins. The process of such formation from an mRNA template is known as translation, which is part of protein synthesis.\nPhenylalanine is one of the standard amino acids.\nEnlarge\nPhenylalanine is one of the standard amino acids.\n\nTwenty amino acids are encoded by the standard genetic code and are called proteinogenic or standard amino acids. Combinations of these amino acids produce every single essential protein for the homeostasis of the human body. At least two others are also coded by DNA in a non-standard manner as follows:\n\n    * Selenocysteine is incorporated into some proteins at a UGA codon, which is normally a stop codon.\n    * Pyrrolysine is used by some methanogens in enzymes that they use to produce methane. It is coded for similarly to selenocysteine but with the codon UAG instead.\n\nOther amino acids contained in proteins are usually formed by post-translational modification, which is modification after translation in protein synthesis. These modifications are often essential for the function of the protein.\n\nProline is the only proteinogenic amino acid whose side group cyclizes onto the backbone: it links to the α-amino group, and thus is also the only proteinogenic amino acid containing a secondary amine at this position. Proline has sometimes been termed an imino acid, but this is not correct by current nomenclature rules.\n\nOver one hundred amino acids have been found in nature. Some of these have been detected in meteorites, especially in a type known as carbonaceous chondrites. Microorganisms and plants can produce uncommon amino acids, which can be found in peptidic antibiotics (e.g., nisin or alamethicin). Lanthionine is a sulfide-bridged alanine dimer which is found together with unsaturated amino acids in lantibiotics (antibiotic peptides of microbial origin). 1-Aminocyclopropane-1-carboxylic acid (ACC) is a small disubstituted cyclic amino acid and a key intermediate in the production of the plant hormone ethylene.\n\nIn addition to protein synthesis, amino acids have other biologically-important roles. Glycine and glutamate are neurotransmitters as well as standard amino acids in proteins. Many amino acids are used to synthesize other molecules, for example:\n\n    * tryptophan is a precursor of the neurotransmitter serotonin\n    * glycine is one of the reactants in the synthesis of porphyrins such as heme.\n\nNumerous non-standard amino acids are also biologically-important: Gamma-aminobutyric acid is another neurotransmitter, carnitine is used in lipid transport within a cell, ornithine, citrulline, homocysteine, hydroxyproline, hydroxylysine, and sarcosine.\n\nSome of the 20 standard amino acids are called essential amino acids because they cannot be synthesized by the body from other compounds through chemical reactions, but instead must be taken in with food. In humans, the essential amino acids are lysine, leucine, isoleucine, methionine, phenylalanine, threonine, tryptophan, valine. Histidine and arginine are generally considered essential only in children, because of their inability to synthesise them given their undeveloped metabolisms.\n\nThe phrase "branched-chain amino acids" is sometimes used to refer to the aliphatic amino acids: leucine, isoleucine and valine.
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Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons by two atoms in order to produce a mutual attraction; atoms tend to share electrons so as to fill their outer electron shells . Such bonds are always stronger than the intermolecular hydrogen bond and similar in strength or stronger than the ionic bond . Commonly covalent bond implies the sharing of just a single pair of electrons. The sharing of two pairs is called a double bond and three pairs is called a triple bond. Aromatic rings of atoms and other resonant structures are held together by covalent bonds that are intermediate between single and double. The triple bond is relatively rare in nature and two atoms are not observed to bond more than triply. \n\nCovalent bonding most frequently occurs between atoms with similar electronegativities where neither atom can provide sufficient energy to completely remove an electron from the other atom. Covalent bonds are more common between non-metals whereas ionic bonding is more common between two metal atoms or a metal and a non-metal atom.
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That guy is wrong.  It is not DNA.  DNA is a double-helix composed of a sugar-phosphate backbone with a nucleic acid on each side of the "ladder."\n\nA polypeptide chain is what you have when you join amino acids.\nIf you join enough of them (usually many) you have a protein.\n\nProtein and polypeptide chain are almost synonomous, but proteins can have very lentgthy, interacting 3-dimensional structures, and the are made of polypeptide chains composed of amino acids joined by polypeptide bonds.
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Molecules are made of atoms
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"Normal" bonding occurs when a ligand donates electrons to a metal. When a metal ion donates electrons back to the ligand, this is called back-bonding. The combination of normal bonding and back-bonding creates a strong bond between the ligand and the metal. The reason that phosphines, carbon monoxide, and cyanide are so poisonous is because they bond readily to iron in biological systems and cannot be displaced by the ligands (such as oxygen) which should bond to iron in normal metabolic processes.
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Splitting any peptide into individual amino acids is called hydrolysis - literally 'splitting with water'. The amide bond is cleaved by addition of water : R-CO-NH-R' + H20 -> R-COOH + H2N-R'\nIn the body, reactions like this are catalysed by enzymes - usually peptidases. In the lab, you can do it easily by boiling the peptide in concentrated HCl overnight.
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Force holding atoms in a molecule together as a specific, separate entity (as opposed to, e.g., colloidal aggregates; see bonding).\n\nIn covalent bonds, two atoms share one or more pairs of valence electrons to give each atom the stability found in a noble gas. In single bonds (e.g., H-H in molecular hydrogen), one electron pair is shared; in double bonds (e.g., O=O in molecular oxygen or H2C=CH2 in ethylene), two; in triple bonds (e.g., HCºCH in acetylene), three. In coordinate covalent bonds, additional electron pairs are shared with another atom, usually forming a functional group, such as sulfate (SO4) or phosphate (PO4). The number of bonds and the atoms participating in each (including any additional paired electrons) give molecules their configuration; the slight negative and positive charges at the opposite ends of a covalent bond are the reason most molecules have some polarity (see electrophile; nucleophile). Carbon in organic compounds can have as many as four single bonds, each pointing to one vertex of a tetrahedron; as a result, certain molecules exist in mirror-image forms (see optical activity). Double bonds are rigid, leading to the possibility of geometric isomers (see isomerism). Some types of bonds, such as the amide linkages that join the amino acids in peptides and proteins (peptide bonds), are apparently single but have some double-bond characteristics because of the electronic structure of the participating atoms. The configurations of enzymes and their substrates, determined by their covalent bonds (particularly the peptide bonds) and hydrogen bonds, are crucial to the reactions they participate in, which are fundamental to all life
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Its covalent.  When two atoms(or more) share one or more electrons, covalent bonds are formed.