Complete The Table About Macromolecules.

Discuss biological macromolecules and the differences between the four classes

As we've learned, there are four major classes of biological macromolecules:

Proteins (polymers of amino acids)
Carbohydrates (polymers of sugars)
Lipids (polymers of lipid monomers)
Nucleic acids (DNA and RNA; polymers of nucleotides)

Permit's accept a closer look at the differences betwixt the departure classes.

Learning Objectives

Define the term "macromolecule"
Distinguish betwixt the iv classes of macromolecules

Now that we've discussed the iv major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), let'southward talk about macromolecules as a whole. Each is an of import cell component and performs a broad assortment of functions. Combined, these molecules make upwardly the majority of a cell'south dry mass (recall that water makes upwards the bulk of its complete mass). Biological macromolecules are organic, meaning they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, and additional minor elements.

You are What You Eat

Comparison the Biological Macromolecules

Macromolecule	Basic Formula, key features	Monomer	Examples	Uses
Proteins	CHON −NH₂ + −COOH +R group	Amino acids	Enzymes, some hormones	Storage; Signals; Structural; Contractile; Defensive; Enzyme; Send; Receptors
Lipids	C:H:O Greater than 2:1 H:O (carboxyl group)	Fatty acid and glycerol	Butter, oil, cholesterol, beeswax	Energy storage; Protection; Chemical messengers; Repel water
Carbohydrates	C:H:O 1:ii:i	Monosaccharides	Glucose, Fructose, Starch, Glycogen, Cellulose	Free energy storage; Structure
Nucleic Acids	CHONP pentose, nitrogenous base, phosphate	Nucleotides	Dna, RNA	Genetic information

Dehydration Synthesis

Near macromolecules are fabricated from single subunits, or building blocks, chosenmonomers. The monomers combine with each other using covalent bonds to class larger molecules known aspolymers. In doing and so, monomers release water molecules as byproducts. This type of reaction is known asaridity synthesis, which means "to put together while losing water."

Shown is the reaction of two glucose monomers to form maltose. When maltose is formed, a water molecules is released.

Figure i. In the dehydration synthesis reaction depicted above, ii molecules of glucose are linked together to course the disaccharide maltose. In the process, a h2o molecule is formed.

In a dehydration synthesis reaction (Figure 1), the hydrogen of one monomer combines with the hydroxyl grouping of another monomer, releasing a molecule of water. At the same time, the monomers share electrons and form covalent bonds. As additional monomers join, this chain of repeating monomers forms a polymer. Dissimilar types of monomers tin combine in many configurations, giving ascension to a diverse group of macromolecules. Even one kind of monomer can combine in a multifariousness of ways to form several different polymers: for instance, glucose monomers are the constituents of starch, glycogen, and cellulose.

Hydrolysis

Polymers are broken down into monomers in a process known equally hydrolysis, which ways "to split h2o," a reaction in which a h2o molecule is used during the breakdown (Figure 2). During these reactions, the polymer is cleaved into 2 components: one part gains a hydrogen atom (H+) and the other gains a hydroxyl molecule (OH–) from a split h2o molecule.

Shown is the breakdown of maltose to form two glucose monomers. Water is a reactant.

Figure ii. In the hydrolysis reaction shown here, the disaccharide maltose is broken down to grade two glucose monomers with the addition of a water molecule. Note that this reaction is the reverse of the synthesis reaction shown in Figure one.

Aridity andhydrolysis reactions are catalyzed, or "sped up," by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions intermission bonds and release energy. These reactions are similar for nearly macromolecules, simply each monomer and polymer reaction is specific for its class. For example, in our bodies, food is hydrolyzed, or broken down, into smaller molecules by catalytic enzymes in the digestive arrangement. This allows for easy assimilation of nutrients by cells in the intestine. Each macromolecule is broken down past a specific enzyme. For instance, carbohydrates are broken down by amylase, sucrase, lactase, or maltase. Proteins are broken downwardly by the enzymes pepsin and peptidase, and by hydrochloric acid. Lipids are broken down past lipases. Breakdown of these macromolecules provides energy for cellular activities.

In Summary: Comparing Biological Macromolecules

Proteins, carbohydrates, nucleic acids, and lipids are the four major classes of biological macromolecules—large molecules necessary for life that are built from smaller organic molecules. Macromolecules are made upwardly of single units known as monomers that are joined by covalent bonds to form larger polymers. The polymer is more than the sum of its parts: it acquires new characteristics, and leads to an osmotic pressure that is much lower than that formed past its ingredients; this is an of import advantage in the maintenance of cellular osmotic conditions. A monomer joins with another monomer with the release of a water molecule, leading to the germination of a covalent bail. These types of reactions are known as aridity or condensation reactions. When polymers are broken downwards into smaller units (monomers), a molecule of water is used for each bond broken past these reactions; such reactions are known as hydrolysis reactions. Dehydration and hydrolysis reactions are similar for all macromolecules, but each monomer and polymer reaction is specific to its course. Aridity reactions typically crave an investment of free energy for new bond formation, while hydrolysis reactions typically release energy past breaking bonds.

Bank check Your Understanding

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