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By the end of this section, you will be able to:
  • Describe the structure and properties of an amine
  • Describe the structure and properties of an amide

Amines are molecules that contain carbon-nitrogen bonds. The nitrogen atom in an amine has a lone pair of electrons and three bonds to other atoms, either carbon or hydrogen. Various nomenclatures are used to derive names for amines, but all involve the class-identifying suffix –ine as illustrated here for a few simple examples:

Three structures are shown, each with a red, central N atom which has a pair of electron dots indicated in red above the N atoms. The first structure is labeled methyl amine. To the left of the N, a C H subscript 3 group is bonded. H atoms are bonded to the right and bottom of the central N atom. The second structure is labeled dimethyl amine. This structure has C H subscript 3 groups bonded to the left and right of the N atom and a single H atom is bonded below. The third structure is labeled trimethyl amine, which has C H subscript 3 groups bonded to the left, right, and below the central N atom.

In some amines, the nitrogen atom replaces a carbon atom in an aromatic hydrocarbon. Pyridine ( [link] ) is one such heterocyclic amine. A heterocyclic compound contains atoms of two or more different elements in its ring structure.

A molecular structure is shown. A ring of five C atoms and one N atom is shown with alternating double bonds. Single H atoms are bonded, appearing at the outside of the ring on each C atom. The N atom has an unshared electron pair shown on the N atom on the outer side of the ring. The N atom, electron dot pair, and bonds connected to it in the ring are shown in red.
The illustration shows one of the resonance structures of pyridine.

Dna in forensics and paternity

The genetic material for all living things is a polymer of four different molecules, which are themselves a combination of three subunits. The genetic information, the code for developing an organism, is contained in the specific sequence of the four molecules, similar to the way the letters of the alphabet can be sequenced to form words that convey information. The information in a DNA sequence is used to form two other types of polymers, one of which are proteins. The proteins interact to form a specific type of organism with individual characteristics.

A genetic molecule is called DNA, which stands for deoxyribonucleic acid. The four molecules that make up DNA are called nucleotides. Each nucleotide consists of a single- or double-ringed molecule containing nitrogen, carbon, oxygen, and hydrogen called a nitrogenous base. Each base is bonded to a five-carbon sugar called deoxyribose. The sugar is in turn bonded to a phosphate group ( −PO 4 3− ) When new DNA is made, a polymerization reaction occurs that binds the phosphate group of one nucleotide to the sugar group of a second nucleotide. The nitrogenous bases of each nucleotide stick out from this sugar-phosphate backbone. DNA is actually formed from two such polymers coiled around each other and held together by hydrogen bonds between the nitrogenous bases. Thus, the two backbones are on the outside of the coiled pair of strands, and the bases are on the inside. The shape of the two strands wound around each other is called a double helix (see [link] ).

It probably makes sense that the sequence of nucleotides in the DNA of a cat differs from those of a dog. But it is also true that the sequences of the DNA in the cells of two individual pugs differ. Likewise, the sequences of DNA in you and a sibling differ (unless your sibling is an identical twin), as do those between you and an unrelated individual. However, the DNA sequences of two related individuals are more similar than the sequences of two unrelated individuals, and these similarities in sequence can be observed in various ways. This is the principle behind DNA fingerprinting, which is a method used to determine whether two DNA samples came from related (or the same) individuals or unrelated individuals.

Diagram a shows DNA as a double helix composed of the nitrogenous bases adenine, thymine, guanine, and cytosine paired up along a sugar-phosphate backbone. The helix has labeled 3 prime and 5 prime directions or ends. In diagram b, the molecular level arrangement of the bases connected by hydrogen bonding within the sugar-phosphate backbone is shown. Adenine is shown with hydrogen bonding to thymine and similarly the linkage via hydrogen bonding between cytosine and guanine is shown. Again, 3 prime and 5 prime directional information is provided. In diagram c, the bonding between a nitrogenous base, sugar, and phosphate is shown.
DNA is an organic molecule and the genetic material for all living organisms. (a) DNA is a double helix consisting of two single DNA strands hydrogen bonded together at each nitrogenous base. (b) This detail shows the hydrogen bonding (dotted lines) between nitrogenous bases on each DNA strand and the way in which each nucleotide is joined to the next, forming a backbone of sugars and phosphate groups along each strand. (c) This detail shows the structure of one of the four nucleotides that makes up the DNA polymer. Each nucleotide consists of a nitrogenous base (a double-ring molecule, in this case), a five-carbon sugar (deoxyribose), and a phosphate group.

Using similarities in sequences, technicians can determine whether a man is the father of a child (the identity of the mother is rarely in doubt, except in the case of an adopted child and a potential birth mother). Likewise, forensic geneticists can determine whether a crime scene sample of human tissue, such as blood or skin cells, contains DNA that matches exactly the DNA of a suspect.

Questions & Answers

How to know periodic table oftend
Ahmed Reply
how to get atomic number of an element
Ogunleye Reply
how do you solve the examples in a much more explanatory way
The reaction of aceto nitrile with propane in the presence of the acid
Explain this paragraph in short
Manish Reply
What is solid state?
Manish Reply
What is chemical reaction
transforming reactants to product(s)
Example of Lewis acid
Chidera Reply
Example of Lewis acid
Anything with an empty orbital... the hydrogen ion is the most common example. BH3 is the typical example, but any metal in a coordination complex can be considered a Lewis acid.
okay thanks
aluminium and sulphur react to give aluminium sulfide.How many grams of Al are required to produce 100g of aluminium sulphide
Soni Reply
aluminium and sulphur react to give aluminium sulphide how many grams of Al are required to produce 100g of aluminium sulphide?
aluminium and sulphur react to give aluminium sulphide how many grams of Al are required to produce 100g of aluminium sulphide?
150 comes from?
thank you very much
molar mass of Al2S3
Why can't atom be created or destroyed
Jacaranda Reply
matter simply converts to pure energy
explain how to distinguish ethanol from a sample of ethanoic acid by chemical test
Alice Reply
explain how ethanol can be distinguished from ethanoic acid by chemical test
Using a suitable experiment, describe how diffusion occurs in gases.
Melody Reply
what is electrolytes?
charity Reply
substance which splits into ions during melting or dissolving
on passing electric current though electrode
what is a radical
Jacob Reply
State that use law of partial pressure in a gas jar containing a gas and water what is the total pressure composed of 272cm^3 of carbon (iv) oxide were collected over water at15°c and 782mmHg pressure. calculate the volume of the dry gas at stp(SVP of water at 15°c is 12mmHg)
Aminat Reply
was Dalton's second postulate"atoms of the same kind have have similar/same mass and size" Or " the one mentioned in B here?
Maureen Reply
what was name of the Greek philosophers
Duku Reply
Practice Key Terms 2

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Source:  OpenStax, Chemistry. OpenStax CNX. May 20, 2015 Download for free at http://legacy.cnx.org/content/col11760/1.9
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