Organic Chemistry, The Building Blocks of Life, Chapter 6.4, Biology

Organic Chemistry ● Organic Chemistry is the study of carbon- based compounds. ● Almost all living organisms contain carbon. ● Carbon is a useful element in the molecules of life because carbon can form four covalent bonds in its outer shell. ● This allows carbon compounds to form straight chain molecules, branched molecules, and ring molecules.

Shapes of Organic Molecules

Macromolecules ● Macromolecules are large molecules that are made by joining smaller molecules together. ● Another name for macromolecules is polymers. ● Polymers are formed by the joining together of smaller monomers that are identical repeating units of the same molecule. ● There are four main types of biological macromolecules; carbohydrates, proteins, lipids (or fats), and nucleic acids (like DNA and RNA)

Carbohydrates ● Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of 1:2:1 respectively (CH 2 O) n where the subscript n represents the number of molecular units. ● Carbohydrates that have n values ranging from 3 to 7 are simple sugars or monosaccharides. ● Two monosaccharides can be joined together to form a polymer called a disaccharide. ● Longer carbohydrate polymers are called polysaccharides.

Carbohydrates ● Monosaccharides (mah nuh SA kuh rids) and Disaccharides (di SA kuh rids) are simple sugars and are easier for the body to break down and give a rapid release of energy. ● Polysaccharides (poly SA kuh rids) are complex sugars and starches that provide more energy but are harder to break down. ● Polysaccharides are used for energy storage and for building structures used for support.

Carbohydrates

● Glycogen is a polysaccharide that is used for energy storage in animals. It is found in abundance in the liver and in muscles. ● When the body needs energy, glycogen can be broken down into glucose. ● Polysaccharides can make other compounds used for support like cellulose in plants and chitin (KI tun) in the exoskeletons of insects.

Polysaccharides ● Glycogen is the dark red material in the cytoplasm of the liver cells. ● Cellulose gives structure and support to plants. ● Chitin gives structure and support to animals with exoskeletons like insects.

Lipids ● Lipids (also known as fats) are made up of mostly carbon and hydrogen. ● Lipids make fats, oils, and waxes. ● The primary function of lipids is to store energy.

Triglycerides ● Triglycerides (tri GLIH suh rid) are lipids that are called fats if they are solid at room temperature and oils if they are liquid at room temperature. ● Triglycerides are stored in fat cells in the body. ● Triglycerides are the main component of vegetable oils and animal fats.

Saturated and Unsaturated Fats ● Fats are made up of long chains of carbon and hydrogen called fatty acids. ● Fatty acids with only single bonds between carbon atoms are called saturated fats because the fatty acids are saturated with hydrogen. ● Fatty acids with at least one double bond between the carbon atoms are referred to as unsaturated fats. ● More than one double bond between the carbon atoms in the fatty acids are referred to as polyunsaturated fats.

Saturated and Unsaturated Fats

Trans Fats ● Trans fats are fats that are formed when liquid fats are made into solids by a process called hydrogenation. This process increases the shelf life of the fats, however this process places the hydrogen on opposite sides of the fatty acid making it inflexible. The more inflexible the fatty acid the more unhealthy the fat.

Phospholipids ● Phospholipids are a type of lipid that the body uses in the cell membrane. ● A phospholipid has a hydrophobic and hydrophilic end. ● This creates a structure called the phospholipid bilayer.

Steroids ● Steroids are lipids that include substances such as cholesterol and important hormones like estrogen and testosterone. ● Cholesterol is vital for many bodily functions but in high amounts it can cause a serious condition known as atherosclerosis. ● Sex hormones such as testosterone and estrogen are responsible for development of sexual characteristics and regulating the menstrual cycle in females.

Cholesterol, Hormones, and Atherosclerosis

Proteins ● Proteins are macromolecules that are made up of amino acids. ● Amino acids are made up of carbon, nitrogen, oxygen, and occasionally sulfur. ● Amino acids have a central carbon atom. ● The central carbon atom is surrounded by an amino group (NH 2 ), a carboxyl group (COOH), a hydrogen atom and some other group called a variable group. ● There are 20 different variable groups.

Protein (Amino Acid) Structure

Peptide Bonds ● When the amino group from one amino acid and the carboxyl group from another amino acid join together, a peptide bond is formed. ● When amino acids join together by peptide bonds, proteins are formed.

Nucleic Acids ● The fourth biological macromolecules are called nucleic acids. ● Nucleic acids carry and transmit genetic information. The two most common forms of nucleic acids are DNA and RNA. ● Nucleic acids are made up of smaller monomers of carbon, nitrogen, oxygen, phosphorus, and hydrogen called nucleotides. ● The chemical groups that make up nucleotides are phosphates, nitrogenous bases, and sugars.

Nucleotide Structure

Adenosine Triphosphate (ATP) ● Another important nucleic acid in biology is called Adenosine Triphosphate or ATP for short. ● ATP is the energy source of the bodies cells. ● ATP has three phosphates. Anytime the body needs energy, one of the phosphates are released from ATP, releasing energy and making a free phosphate and ADP (adenosine diphosphate) molecule. When energy is absorbed, a phosphate is rejoined to the ADP molecule, making an ATP molecule.

Adenosine Triphosphate (ATP)