Carbon’s ability to bond easily and form compounds is the basis of life on Earth. A carbon atom has four electrons in its outer energy level, so it can form four covalent bonds with as many as four other atoms. One of carbon’s most frequent partners in forming covalent bonds is hydrogen. Organic Compounds Simple Organic Compounds 1 1
Substances can be classified into two groups those derived from living things and those derived from nonliving things. Most of the substances associated with living things contain carbon and hydrogen. Scientists use the term organic compound for most compounds that contain carbon. Organic Compounds Simple Organic Compounds 1 1
A compound that contains only carbon and hydrogen atoms is called a hydrocarbon. The simplest hydrocarbon is methane. Methane consists of a single carbon atom covalently bonded to four hydrogen atoms. Hydrocarbons Simple Organic Compounds 1 1
This figure shows a model of the methane molecule and its structural formula. In a structural formula, the line between one atom and another atom represents a pair of electrons shared between the two atoms. Hydrocarbons Simple Organic Compounds 1 1
Here’s a way to visualize how larger hydrocarbons are built up. Hydrocarbons Simple Organic Compounds 1 1
When all the bonds in a hydrocarbon are single bonds, the molecule is called a saturated hydrocarbon. No additional hydrogen atoms can be added to the molecule. Saturated Hydrocarbons Simple Organic Compounds 1 1
Propane, with three carbon atoms, is the third member of the series of saturated hydrocarbons. Butane has four carbon atoms. Saturated Hydrocarbons Simple Organic Compounds 1 1
Saturated hydrocarbons are named with an –ane ending. Another name for these hydrocarbons is alkanes. Page 411 Saturated Hydrocarbons Simple Organic Compounds 1 1
Carbon can form long chains that contain hundreds or even thousands of carbon atoms. Saturated Hydrocarbons Simple Organic Compounds 1 1 These extremely long chains make up many of the plastics that you use.
Hydrocarbons with double or triple bonds are called unsaturated hydrocarbons. Unsaturated Hydrocarbons Simple Organic Compounds 1 1 Ethene, the simplest unsaturated hydrocarbon, has two carbon atoms joined by a double bond.
Unsaturated compounds with at least one double bond are named with an –ene ending. Unsaturated Hydrocarbons Simple Organic Compounds 1 1 These compounds are called alkenes.
Unsaturated hydrocarbons also can have triple bonds, as in the structure of ethyne (EH thine). Triple Bonds Simple Organic Compounds 1 1 Ethyne, is a gas used for welding because it produces high heat as it burns. These unsaturated compounds are called alkynes.
Hydrocarbon Isomers Simple Organic Compounds 1 1 Compounds that have the same molecular formula but different arrangements, or structures, are called isomers (I suh murz). Page 412
Hydrocarbon Isomers Simple Organic Compounds 1 1 Two isomers, butane and isobutane, have different chemical and physical properties because of their different structures.
Some molecules contain rings. Hydrocarbons in Rings Simple Organic Compounds 1 1 The carbon atoms of hexane bond together to form a closed ring containing six carbons.
Hydrocarbons in Rings Simple Organic Compounds 1 1 Many natural substances such as sucrose, glucose, and fructose are ring structures. Ring structures can contain one or more double bonds. The prefix cylco- in their names tells you that the molecules are cyclic or ring shaped.
1 1 Section Check Question 1 A compound that contains only hydrogen and carbon is known as what? A. amino acid B. hydrocarbon B. isomer C. organic compound NC: 4.02
1 1 Section Check Answer The answer is B. The simplest hydrocarbon is methane, a primary component of natural gas. NC: 4.02
1 1 Section Check Question 2 What is a methyl group? A methyl group is a fragment of a methane molecule. In particular, it’s one that can bond with another methyl group to build up a larger hydrocarbon. Answer NC: 4.02
1 1 Section Check Question 3 When all the bonds in a hydrocarbon are single bonds, the molecule is called a(n) _______. A. isomer B. organic compound C. saturated hydrocarbon D. unsaturated hydrocarbon NC: 4.02
1 1 Section Check Answer The answer is C. You can remember this by thinking that the term saturated means “completely full”; no more hydrogen atoms can be added on to the molecule. NC: 4.02
Substituted Hydrocarbons Other Organic Compounds 2 2 To make a substituted hydrocarbon, one or more hydrogen atoms are replaced by atoms such as halogens or by groups of atoms. Chemists change hydrocarbons to make compounds called substituted hydrocarbons.
Substituted Hydrocarbons Other Organic Compounds 2 2 For example, when one or more chlorine atoms are added to methane in place of hydrogens, new compounds are formed. Such changes result in compounds with chemical properties different from the original hydrocarbon.
Alcohols Other Organic Compounds 2 2 The hydroxyl (hi DROK sul) group is made up of an oxygen atom and a hydrogen atom joined by a covalent bond. -OH Groups of atoms also can be added to hydrocarbons to make different compounds.
Alcohols Other Organic Compounds 2 2 This figure shows the formation of the alcohol methanol. An alcohol is formed when a hydroxyl group replaces a hydrogen atom in a hydrocarbon.
Alcohols Other Organic Compounds 2 2 The table lists three alcohols with their structures and uses. Larger alcohol molecules are formed by adding more carbon atoms to the chain.
Carboxylic Acids Other Organic Compounds 2 2 A carboxylic (car BOK sul) group consists of a carbon atom that has a double bond with one oxygen atom and a single bond with a hydroxyl group.
Carboxylic Acids Other Organic Compounds 2 2 Its formula is –COOH. When a carboxyl group is substituted in a hydrocarbon, the substance formed is called a carboxylic acid. The simplest carboxylic acid is formic acid. It is found in bee venom.
Carboxylic Acids Other Organic Compounds 2 2 Many carboxylic acids occur in foods. Citric acid is found in citrus fruits such as oranges and grapefruit. Lactic acid is present in sour milk. Acetic acid dissolved in water vinegar often is used in salad dressings.
Amines Other Organic Compounds 2 2 Amines are a group of substituted hydrocarbons formed when an amino group replaces a hydrogen atom. An amino (uh ME noh) group is a nitrogen atom joined by a covalent bond to two hydrogen atoms. It has the formula –NH 2.
Amino Acids Other Organic Compounds 2 2 When both an amino group (-NH 2 ) and a carboxyl acid group (-COOH) replace hydrogens on the same carbon atom in a molecule, a type of compound known as an amino acid is formed. Amino acids are essential for human life.
The Building Blocks of Protein Other Organic Compounds 2 2 Amino acids are the building blocks of proteins, which are an important class of biological molecules needed by living cells. Twenty different amino acids bond in different combinations to form the variety of proteins that are needed in the human body.
The Building Blocks of Protein Other Organic Compounds 2 2 Glycine is the simplest amino acid. It is a methane molecule in which one hydrogen atom has been replaced by an amine group and another has been replaced by a carboxyl group.
2 2 Section Check Question 1 You can take a hydrocarbon and create a compound with differing properties by replacing some of the hydrogen atoms with halogens. The result will be a _______. Answer The result is a substituted hydrocarbon. You could also add on groups of new atoms. NC: 4.02
2 2 Section Check Question 2 What does this symbol stand for? –OH NC: 4.02
2 2 Section Check Answer The symbol refers to a hydroxyl group. NC: 4.02
2 2 Section Check Question 3 What do you call a carbon atom that has a double bond with one oxygen atom and, at the same time, a single bond with a hydroxyl group? A. amino group B. carboxyl group C. hydroxyl group D. polymer NC: 4.02
2 2 Section Check Answer The answer is B. Its formula is -COOH. NC: 4.02
What’s a polymer? Biological Compounds 3 3 A polymer is a molecule made up of many small organic molecules linked together with covalent bonds to form a long chain. The small, organic molecules that link together to form polymers are called monomers.
What’s a polymer? Biological Compounds 3 3 Polymers produced by living organisms are called natural polymers. Polymers made in a laboratory are called synthetic polymers.
What’s a polymer? Biological Compounds 3 3 The unsaturated hydrocarbon ethylene, C 2 H 4, is the monomer of a common polymer used often in plastic bags. The monomers are bonded together in a chemical reaction called polymerization (puh lih muh ruh ZAY shun).
What’s a polymer? Biological Compounds 3 3 The carbon atoms that were joined by the double bond each have an electron to share with another carbon in another molecule of ethylene. The process goes on until a long molecule is formed.
Proteins are Polymers Biological Compounds 3 3 A protein is a polymer that consists of a chain of individual amino acids linked together. Your body cannot function properly without them.
Proteins are Polymers Biological Compounds 3 3 The various functions in your body are performed by different proteins. Your body makes many of these proteins by assembling 20 amino acids in different ways. Eight of the amino acids that are needed to make proteins cannot be produced by your body. These amino acids, which are called essential amino acids, must come from the food you eat.
Proteins are Polymers Biological Compounds 3 3 The process by which your body converts amino acids to proteins is shown.
Carbohydrates Biological Compounds 3 3 A carbohydrate is an organic compound that contains only carbon, hydrogen, and oxygen, usually in a ratio of two hydrogen atoms to one oxygen atom. The different types of carbohydrates are divided into groups sugars, starches, and cellulose.
Carbohydrates Biological Compounds 3 3 Glucose and fructose are simple six-carbon carbohydrates found in many fresh and packaged foods. Glucose and fructose are isomers.
Sugars Biological Compounds 3 3 Simple sugars are carbohydrates containing five, six, or seven carbon atoms arranged in a ring.
Starches Biological Compounds 3 3 Starches are polymers of glucose monomers in which hundreds or even thousands of glucose molecules are joined together. Starches are sources of large amounts of energy.
Other Glucose Polymers Biological Compounds 3 3 Two other important polymers that are made up of glucose molecules are cellulose and glycogen. Cellulose makes up the long, stiff fibers found in the walls of plant cells. It is a polymer that consists of long chains of glucose units linked together.
Other Glucose Polymers Biological Compounds 3 3 Glycogen is a polymer that also contains chains of glucose units, but the chains are highly branched. Animals make glycogen and store it mainly in their muscles and liver as a ready source of glucose.
Lipids Biological Compounds 3 3 A lipid is an organic compound that contains the same elements as carbohydrates carbon, hydrogen, and oxygen but in different proportions.
Lipids Store Energy Biological Compounds 3 3 Lipids store energy in their bonds, just as carbohydrates do, but they are a more concentrated source of energy than carbohydrates. If you eat more food than your body needs to supply you with the energy for usual activities, the excess energy from the food is stored by producing lipids.
Lipids Store Energy Biological Compounds 3 3 The chemical reaction that produces lipids is endothermic. An endothermic reaction is one in which energy is absorbed. This means that energy is stored in the chemical bonds of lipids. When your body needs energy, the bonds are broken and energy is released.
Saturated and Unsaturated Lipids Biological Compounds 3 3 Lipid molecules can be saturated or unsaturated. When a lipid is saturated, the acid chains are straight because all the bonds are single bonds.
Saturated and Unsaturated Lipids Biological Compounds 3 3 When a lipid is unsaturated the molecule bends wherever there is a double bond. This prevents the chains from packing close together.
Saturated and Unsaturated Lipids Biological Compounds 3 3 Doctors have observed that people who eat a diet high in saturated fats have an increased risk of developing cardiovascular problems such as heart disease. The effect of saturated fat seems to be increased blood cholesterol, which may be involved in the formation of deposits on artery walls.
Cholesterol Biological Compounds 3 3 Cholesterol is a complex lipid that is present in foods that come from animals, such as meat, butter, eggs, and cheese. Even if you don’t eat foods containing cholesterol, your body makes its own supply. Your body needs cholesterol for building cell membranes.
Cholesterol Biological Compounds 3 3 Deposits of cholesterol, called plaque, can build up on the inside walls of arteries. This condition is known as atherosclerosis.
Cholesterol Biological Compounds 3 3 When arteries become clogged, the flow of blood is restricted, which results in high blood pressure. This, in turn, can lead to heart disease.
3 3 Section Check Question 1 A molecule composed of many smaller molecules linked into a chain with covalent bonds is called a ________. It is called a polymer; the prefix “poly,” means “many.” Answer NC: 4.02
3 3 Question 2 Section Check A carbohydrate is an organic compound that contains carbon, hydrogen, and _______. NC: 4.02
3 3 Answer Section Check The answer is oxygen. In the body, carbohydrates are broken down into simple sugars that the body can use for energy. NC: 4.02
3 3 Question 3 Section Check Carbohydrates containing five, six or seven carbon atoms arranged in a ring shape are known as _______. A. amino acids B. proteins C. sugars D. unsaturated carbohydrates NC: 4.02
3 3 Answer Section Check The answer is C. Whenever you eat a grape, you are eating carbon rings. NC: 4.02
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