Thread: What kinda bond is this?

I understand that Colalent bonds hold each compound together, but what kind of bond holds the amino acid together?

Originally Posted by astrogirl15

I understand that Colalent bonds hold each compound together, but what kind of bond holds the amino acid together?

In histidine you have covalent bonds. If you combine, for example, histidine and phenylalanine, they are also combined by a covalent bond, i.e. the so called peptide bond.

What holds all the compounds that make up Histidine together?

Originally Posted by astrogirl15

What holds all the compounds that make up Histidine together?

Covalent bonds? Or do you mean anything different? :?

george pls dont answer my questions. thanks for your intent.. but your not helping

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Your question is not very clear. There are several types of bonds within the histidine molecule. I am guessing that you are referring specifically to the two charged groups, the NH3+ and the COO- groups.

The extra proton in the NH3+ group is held by a bond that is essentially ionic in nature.

The loss of the proton from the -COOH yields a resonant stucture, with electrons shifting back and forth equally between the two carbon-oxygen bonds. It is essentially covalent with strong ionic properties.

Few molecules have bonds that are purely covalent or purely ionic. They typically share properties of each.

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Ok let me see if i can help, George was answering the question correctly so maybe the question you are asking was a bit ambiguos.

So The individual atoms of one his molecule are all held together by covalent bonds. e.g C---H is a covalent bond..

However between His molecules there exist other types of bonding.

You can see that the amino acid in this form the "zwitterion" has both a negative and positive charge. This means that between neighbouring zwitterions there will be ionic bonding due to electrostatic attraction between opposite charges, i.e COO^- on one molecule ionically bonds to a NH₄⁺ of another molecule.

This is what gives amino acids relatively high boiling boints compared to other organic compounds, hope this clears things up