Monomers group together to form long chains of macromolecules called proteins and fats derives from the linkage of several monomers. A macromolecule is a class of biomolecules that are made of monomers. These include polysaccharides (i.e. sugars) polypeptides (i.e. Explain the relationship among atoms, elements, and compounds. Explain the relationship between monomers and polymers, using polysaccharides as an example. Polymers are large macromolecules made up of smaller molecules called.
A helical structure consists of repeating units that lie on the wall of a cylinder such that the structure is superimposable upon itself if moved along the cylinder axis. A helix looks like a spiral or a screw.
A zig-zag is a degenerate helix. Helices can be right-handed or left handed. The difference between the two is that: Right-handed helices or screws advance move away if turned clockwise. Left-handed helices or screws advance move away if turned counterclockwise.
Helical organization is an example of secondary structure. These helical conformations of macromolecules persist in solution only if they are stabilized. What might carry out this stabilization? Stable biological helices are usually maintained by hydrogen bonds. Let's now look at Helices in carbohydrates. Starch amylose exemplifies this structure. The starch helix is not very stable in the absence of other interactions iodine, which forms a purple complex with starch, stabilized the starch helixand it commonly adopts a random coil conformation in solution.
Cellulose exemplifies this structure. Cellulose is a degenerate helix consisting of glucose units in alternating orientation stabilized by intrachain hydrogen bonds. Cellulose chains lying side by side can form sheets stabilized by interchain hydrogen bonds. Helices in nucleic acids. Single chains of nucleic acids tend to from helices stabilized by base stacking. The purine and pyrimidine bases of the nucleic acids are aromatic rings.
These rings tend to stack like pancakes, but slightly offset so as to follow the helix. The stacks of bases are in turn stabilized by hydrophobic interactions and by van der Waals forces between the pi-clouds of electrons above and below the aromatic rings. In these helices the bases are oriented inward, toward the helix axis, and the sugar phosphates are oriented outward, away from the helix axis. Two lengths of nucleic acid chain can form a double helix stabilized by Base stacking Hydrogen bonds.
Purines and pyrimidines can form specifically hydrogen bonded base pairs. Let's look at how these hydrogen bonds form. Guanine and cytosine can form a base pair that measures 1. Adenine and thymine or uracil can form a base pair that measures 1. Base pairs of this size fit perfectly into a double helix.
Types of Monomers | Sciencing
This is the so-called Watson-Crick base pairing pattern. A must always be opposite T or U. G must always be opposite C. Here's a sample of two complementary sequences. It is important to note, though, that the complementary sequences forming a double helix have opposite polarity. The two chains run in opposite directions: This arrangement allows the two chains to fit together better than if they ran in the same direction parallel arrangement.
In any double helical structure the amount of A equals the amount of T or Uand the amount of G equals the amount of C. T's, G's and C's in this or any arbitrary paired sequence to prove this to yourself. Three major types of double helix occur in nucleic acids.
These three structures are strikingly and obviously different in appearance.
You could see the difference if it were out of focus, and you could feel the differences in the dark. Such as the enzymes that control the expression of genetic information. DNA usually exists in the form of a B-helix. Right-handed and has 10 nucleotide residues per turn. The plane of the bases is nearly perpendicular to the helix axis. There is a prominent major groove and minor groove. The B-helix may be stabilized by bound water that fits perfectly into the minor groove.
Right-handed and has 11 nucleotide residues per turn. The plane of the bases is tilted relative to the helix axis. The minor groove is larger than in B-DNA.
This is a stabilizing factor you should know. Left-handed this surprised the discoverers and has 12 residues 6 PuPy dimers per turn. The phosphate groups lie on a zig-zag line, which gives rise to the name, Z-DNA. Z-DNA is stabilized if it contains modified methylated cytosine residues. The detailed shape of the helix determines the interactions in which it can engage. The geometry of the grooves are important in allowing or preventing access to the bases.
The surface topography of the helix forms attachment sites for various enzymes sensitive to the differences among the helix types. We'll see some detailed examples of this later. The DNA triplex triple helix: Start by imagining a B-DNA helix. It is possible under certain circumstances to add a third helix fitting it into the major groove.
A triplex can form ONLY if one strand of the original B-helix is all purines A and G [why you need to know purines from pyrimidines] and the corresponding region of the other strand is all pyrimidines. The triplex is stabilized by H-bonds in the unusual Hoogsteen base-pairing pattern shown in the slide along with standard Watson-Crick base pairing.
The existence of this structure was known for 20 years, but no one knew what to make of it. Now, recognizing that it occurs naturally in gene control regions, it is getting a great deal of attention in the research literature.
Currently artificial oligonucleotide drugs are being synthesized that form triplexes with specific natural DNA sequences. Other drugs are being developed that stabilize naturally occurring or artificial triplexes. These are showing promise as antitumor and antibacterial agents, as well as potential agents to modify enzyme activity by controlling enzyme synthesis.
It's too new to be in even the most modern text, but you will be seeing more and more of this in the near future. Be aware of this structure, know where it is found in the gene at control regions and its effect on gene expression, and that it is the subject of promising clinical investigations. Properties of the peptide bond dominate the structures of proteins. The first of these properties is that the peptide bond has partial double character. Chitin is an important polysaccharide used to make the exoskeletons of arthropods.
Lipids Lipids are all similar in that they are at least in part hydrophobic. There are three important families of lipids: Fats Fats are large molecules made of two types of molecules, glycerol and some type of fatty acid. The fatty acid has a long chain of carbon and hydrogen, usually referred to as the hydrocarbon tail, with a carboxyl group head. The carboxyl group is why its called an acid.
Glycerol has three carbons 3. These can be the same three or different. This arrangement of three is why fats are called triglycerides. Fats may be saturated or unsaturated.
This has to do with the amount of hydrogen in the tail. Unsaturated fatty acids have some hydrogen missing, with double bonds replacing them. The double bond give the fatty acid a kink 3. Saturated fats are solid at room temperature and come from animals, unsaturated fats come from plants and are liquid at room temperature. Fats are used as a high density energy storage in animals and in plants seeds.
It may also be used in animals for insulation. Phospholipids Phospholipids are like fats but they have two fatty acids and a phosphate group joined to glycerol.
The fatty acid tails are hydrophobic but the phosphate part is hydrophilic. This is an important feature of these molecules. More about phospholipids when we cover membrane structure. Steroids Steroids are also lipids but they have a carbon skeleton of four connected rings no glycerol here 3. The different properties of different steroids are due to the attached functional groups. Cholesterol is a steroid that can be modified to form many hormones. Proteins Proteins are extremely important.
They are large, complex molecules that are used for structural support, storage, to transport substances, and as enzymes. They are a sophisticated, diverse group of molecules, and yet they are all polymers of just 20 amino acids. Amino acids have a carbon attached to a hydrogen, an amino group, a carboxyl group and something else R.
Its the something else that give the amino acid its characteristics 3. Amino acids are joined together by peptide bonds dehydration synthesis 3. Polypeptide chains are strings of amino acids, joined by peptide bonds. Proteins are formed by twisting up one or more poly peptide chains.
It is the shape, or conformation, of the protein that gives it its properties. There are four levels of protein structure. Primary structure is the unique series of amino acids. The secondary structure results from hydrogen bonds along the chain which cause repeated coiled or folded patterns. Several amino acid monomers join via peptide covalent bonds to form a protein. Two bonded amino acids make up a dipeptide. Three amino acids joined make up a tripeptide, and four amino acids make up a tetrapeptide.
With this convention, proteins with over four amino acids also bear the name polypeptides.
Carbohydrates (article) | Macromolecules | Khan Academy
Of these 20 amino acids, the base monomers include glucose with carboxyl and amine groups. Glucose can therefore also be called a monomer of protein. The amino acids form chains as a primary structure, and additional secondary forms occur with hydrogen bonds leading to alpha helices and beta pleated sheets.
Folding of amino acids leads to active proteins in the tertiary structure. Additional folding and bending yields stable, complex quaternary structures such as collagen. Collagen provides structural foundations for animals. The protein keratin provides animals with skin and hair and feathers.
Proteins also serve as catalysts for reactions in living organisms; these are called enzymes. Proteins serve as communicators and movers of material between cells. For example, the protein actin plays the role of transporter for most organisms.
The varying three-dimensional structures of proteins lead to their respective functions. Changing the protein structure leads directly to a change in protein function. Nucleotides as Monomers Nucleotides serve as the blueprint for the construction of amino acids, which in turn comprise proteins.
Nucleotides store information and transfer energy for organisms. Nucleotides are the monomers of natural, linear polymer nucleic acids such as deoxyribonucleic acid DNA and ribonucleic acid RNA. Nucleotide monomers are made of a five-carbon sugar, a phosphate and a nitrogenous base. Bases include adenine and guanine, which are derived from purine; and cytosine and thymine for DNA or uracil for RNAderived from pyrimidine. The combined sugar and nitrogenous base yield different functions.
Nucleotides form the basis for many molecules needed for life. One example is adenosine triphosphate ATPthe chief delivery system of energy for organisms. Adenine, ribose and three phosphate groups make up ATP molecules. Phosphodiester linkages connect the sugars of nucleic acids together. These linkages possess negative charges and yield a stable macromolecule for storing genetic information.
RNA, which contains the sugar ribose and adenine, guanine, cytosine and uracil, works in various methods inside cells. RNA exists in a single-helix form. DNA is the more stable molecule, forming a double helix configuration, and is therefore the prevalent polynucleotide for cells. DNA contains the sugar deoxyribose and the four nitrogenous bases adenine, guanine, cytosine and thymine, which make up the nucleotide base of the molecule.
The long length and stability of DNA allows for storage of tremendous amounts of information. Monomers for Plastic Polymerization represents the creation of synthetic polymers via chemical reactions. When monomers are joined together as chains into manmade polymers, these substances become plastics. The monomers that make up polymers help determine the characteristics of the plastics they make. All polymerizations occur in a series of initiation, propagation and termination.
Polymerization requires various methods for success, such as combinations of heat and pressure and the addition of catalysts. Polymerization also requires hydrogen to end a reaction.
Different factors in the reactions influence the branching or chains of a polymer.