Biochem 1.2 Amino Acid Properties Overview

Amino acids with side chains composed primarily of carbon and hydrogen atoms, making them nonpolar and hydrophobic. These residues prefer interactions with other nonpolar molecules and tend to be located in the interior of proteins or within cell membranes.

The distinct chemical characteristics of an amino acid, primarily determined by its side chain.

The portion of an amino acid that extends beyond the backbone, providing it with unique chemical properties.

Amino acids that contain atoms other than carbon and hydrogen in their side chains, such as oxygen, nitrogen, or sulfur.

A type of bond between atoms that involves sharing electrons equally, resulting in a balanced distribution of charge.

The tendency of nonpolar molecules to avoid contact with water, often clustering together in a hydrophobic environment. This property is crucial in protein folding and membrane formation.

The ability of a molecule to form hydrogen bonds, a type of interaction involving a hydrogen atom and a highly electronegative atom like oxygen or nitrogen.

A type of interaction that involves a shared pair of electrons between two atoms, holding them together.

Regions of a molecule that possess a partial positive charge, due to the electronegativity of atoms like oxygen or nitrogen.

A large amino acid with a side chain containing an indole ring, making it relatively nonpolar despite having a nitrogen atom.

Nonpolar amino acids that do not contain an aromatic ring, like glycine, alanine, methionine, valine, leucine, isoleucine, and proline.

Amino acids with a branched alkyl chain, including valine, leucine, and isoleucine.

Nonpolar amino acids containing a fully conjugated, aromatic ring structure, like phenylalanine, tryptophan, and tyrosine.

The property of a molecule having a slight difference in electrical charge distribution, making one end slightly positive and the other slightly negative.

Amino acids whose side chains have significant polar character, but do not carry a dominant charge under physiological conditions, like serine, threonine, asparagine, glutamine, cysteine, and tyrosine.

The study of how living organisms function on a molecular level, including the chemical reactions that occur within their cells.

A group of atoms other than carbon and hydrogen.

A specific arrangement of atoms in a molecule, particularly a closed ring structure.

The process by which the body breaks down and uses nutrients for energy, growth, and repair.

A change in the structure or function of a living organism, often due to disease or injury.

The side chain of an amino acid that contains a hydroxyl group linked to a phenyl ring, making it more polar and hydrophilic than other aromatic amino acids. Its hydroxyl group is more accessible than other alcohols, making it easier to donate a proton.

The tendency of a molecule to form hydrogen bonds, which involve a hydrogen atom interacting with a highly electronegative atom like oxygen or nitrogen. These bonds contribute to the stability and structure of molecules.

The ability of a molecule to dissolve in water due to its polar nature. This is often attributed to the presence of polar functional groups, like hydroxyl groups, that can form hydrogen bonds with water molecules.

The amino acids with polar side chains that contain oxygen and nitrogen atoms. These atoms have significant dipole moments, making them capable of interacting with water molecules, thus contributing to their solubility in aqueous environments.

The process of removing a proton (H+) from a molecule, resulting in a negative charge. This can occur in amino acids with certain side chains under specific conditions, contributing to their charge properties.

The property of a molecule that prefers to interact with other nonpolar molecules and tends to avoid contact with water. This is often attributed to the presence of nonpolar functional groups, like hydrocarbon chains, which cannot form strong interactions with water molecules.

A type of chemical bond involving a shared pair of electrons between two atoms, holding them together. This type of bond is strong and contributes to the stability of molecules.

The tendency of nonpolar molecules to cluster together in a watery environment, avoiding contact with water molecules. This property is important in protein folding and membrane formation.

A type of molecule that is attracted to water due to its polar nature. These molecules have functional groups, such as hydroxyl groups, that can form hydrogen bonds with water molecules, making them readily soluble in water.

The side chain of cysteine, containing a sulfur atom. This group is weakly polar and cannot form hydrogen bonds with water, but it can interact with water through dipole-induced dipole interactions.

Cysteine is often classified as a neutral amino acid, but at physiological pH, a small portion of its side chains can lose a proton and become negatively charged.

While histidine is often grouped with basic amino acids due to its ability to become positively charged, at physiological pH, most of its side chains have lost their proton and are uncharged. Only a small percentage remain protonated.

These amino acids carry a positive charge on their side chains at physiological pH. They are classified as basic amino acids because they accept protons from their environment.

Lysine and arginine are the primary examples of positively charged amino acids. Most of their side chains are protonated and positively charged at physiological pH.

Histidine, while often included with basic amino acids, is primarily neutral at physiological pH. Only a small percentage of its side chains are protonated and positively charged.

These amino acids carry a negative charge on their side chains at physiological pH. They are classified as acidic amino acids because they donate protons to their environment.

Aspartate and glutamate are the primary examples of negatively charged amino acids. Most of their side chains have lost a proton and are negatively charged at physiological pH.

The side chain of a charged amino acid is responsible for the electrical charge that it carries. These charges play significant roles in protein function and interactions.

Charged amino acids are essential for protein structure and function. They contribute to the stability of proteins and enable interactions with other molecules, such as DNA, RNA, and other proteins.

The charge of an amino acid is determined by its ability to gain or lose protons (H+) at a given pH.