An example of a hydrophobic group is the non-polar methane molecule. Among the hydrophilic functional groups is the carboxyl group found in amino acids, some amino acid side chains, and the fatty acids that form triglycerides and phospholipids. Other functional groups, such as the carbonyl group, have a partially negatively charged oxygen atom that may form hydrogen bonds with water molecules, again making the molecule more hydrophilic. Hydrogen bonds between functional groups within the same molecule or between different molecules are important to the function of many macromolecules and help them to fold properly into and maintain the appropriate shape for functioning.
Functional groups include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. Key Terms hydrophobic : lacking an affinity for water; unable to absorb, or be wetted by water hydrophilic : having an affinity for water; able to absorb, or be wetted by water.
Location of Functional Groups Functional groups are groups of atoms that occur within organic molecules and confer specific chemical properties to those molecules. Properties of Functional Groups A functional group can participate in specific chemical reactions. Classifying Functional Groups Functional groups are usually classified as hydrophobic or hydrophilic depending on their charge or polarity.
Hydrogen Bonds between Functional Groups Hydrogen bonds between functional groups within the same molecule or between different molecules are important to the function of many macromolecules and help them to fold properly and maintain the appropriate shape needed to function correctly.
Provided by : Boundless. A functional group can participate in specific chemical reactions. Some of the important functional groups in biological molecules include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups.
These groups play an important role in the formation of molecules like DNA, proteins, carbohydrates, and lipids. Functional groups are usually classified as hydrophobic or hydrophilic depending on their charge or polarity. An example of a hydrophobic group is the non-polar methane molecule. Among the hydrophilic functional groups is the carboxyl group found in amino acids, some amino acid side chains, and the fatty acid heads that form triglycerides and phospholipids.
Other functional groups, such as the carbonyl group, have a partially negatively charged oxygen atom that may form hydrogen bonds with water molecules, again making the molecule more hydrophilic. Simple structure Sulfhydryl Polar Characterized by presence of S. Characterized by central C bound to O and OH. Characterized by presence of N.
The simplest example of a covalent bond is that between two hydrogen H atoms to form H2. Sometimes, the two atoms involved in a covalent bond do not share the electrons equally and the bond is called a polar covalent bond. Ionic bonds form when one atom donates electrons to another. They often form between an atom that contains a filled outer electron shell plus just one or two electrons and an atom that is just one or two electrons shy of filling its outer electron shell — the atoms achieve a completely filled outer electron shell by transferring and receiving electrons, respectively.
The electron donor atom acquires a net positive charge i. The cation and anion have equal and opposite charges, and they form an ionic bond based on their attraction to each other.
Hydrogen bonds are a type of polar interaction that occur when an H atom is covalently bonded to a very electronegative atom i. The electronegative atoms include oxygen O , nitrogen N , and fluorine F. When hydrogen is bonded to O, N, or F, the electronegative atom pulls the electrons away from the H atom and toward itself, which leaves the H atom with a partial positive charge and the electronegative atom i.
The H atom with a partial positive charge acts as a hydrogen bond donor when it is bonded with O, N, or F. Electronegative O, N, and F atoms act as hydrogen bond acceptors, regardless of whether they are bonded with H.
As you likely know, each water molecule is made up of a central O atom covalently linked to two H atoms. The bonds between the O and H atoms are highly polar because O has a high affinity for electrons and H has only a weak affinity for electrons.
As a result, water molecules exhibit an unequal distribution of their electrons: The O atom pulls most of the electrons away from the H atoms and toward itself. This results in the O atom taking on a partial negative charge it has more electrons associated with it and the H atoms taking on a partial positive charge their electrons are being pulled away from them by the O atom.
Because water molecules are polar, they are attracted to each other — the negatively charged O atom of one water molecule forms hydrogen bonds with the positively charged H atoms of other water molecules. You might be surprised to read that hydrogen bonds play a key role in maintaining the double helix structure of DNA and in directing the proper folding of proteins. Although hydrogen bonds are much weaker than covalent bonds, they play invaluable roles in our cells!
They are associated with nonpolar atoms. As you may know, the cloud of electrons around any nonpolar atom fluctuates over time and sometimes forms a dipole.
These dipoles will occasionally induce the formation of a brief dipole of the opposite charge in a nearby atom. The two atoms with oppositely charged dipoles will momentarily be attracted to each other. Although van der Waals attractions are very weak, they can add up to significant effects in cells when the surfaces of many atoms come in close contact with each other.
Can we review the different macromolecules and their purpose? Hello Shannon, Macromolecules are key building blocks of our cells. There are four main classes of biological macromolecules, including proteins, nucleic acids, carbohydrates, and lipids.
As their name suggests, macromolecules are large molecules i. Proteins also called polypeptides are made up of amino acid monomers joined via peptide bonds.
Each amino acid comprises a central carbon atom linked to a carboxylic acid group, a nitrogen-containing group called an amine, a hydrogen atom, and one of twenty different side chain groups that defines the amino acid.
0コメント