Lesson Overview 2.3 Carbon Compounds

THINK ABOUT IT In the early 1800s, many chemists called the compounds created by organisms “organic,” believing they were fundamentally different from compounds in nonliving things. Today, -organic chemistry means the study of compounds that contain bonds between carbon atoms, -inorganic chemistry is the study of all other compounds.

The Chemistry of Carbon What elements does carbon bond with to make up life’s molecules? Carbon can bond with: -other carbon atoms, -many other elements

The Chemistry of Carbon Carbon atoms -have four valence electrons, -can form four covalent bonds, -can bond with other carbon atoms, -can bond with other elements including hydrogen, oxygen, phosphorus, sulfur, and nitrogen. Living organisms are made up of molecules that consist of carbon and these other elements. Elements of life: Remember CHONPS

The Chemistry of Carbon Because carbon atoms can bond to each other: -carbon atoms have the ability to form millions of different large and complex structures, -carbon-carbon bonds can be single, double, or triple covalent bonds, -chains of carbon atoms can even close up on themselves to form rings.

Macromolecules -”giant molecules”, -made from thousands or even hundreds of thousands of smaller molecules, -make up many organic compounds in living cells, -formed by the process of polymerization, in which large compounds are built by joining smaller ones together.

Macromolecules -Smaller units of macromolecules are called monomers, -monomers are joined together to form polymers, -monomers in a polymer may be identical or different.

Macromolecules Biochemists sort macromolecules found in living things into groups based on their chemical composition. The four major groups of macromolecules found in living things are -carbohydrates, -lipids, -nucleic acids, and -proteins.

Macromolecules What are the functions of each of the four groups of macromolecules? Living things use carbohydrates as their main source of energy.

Carbohydrates -compounds made up of carbon, hydrogen, and oxygen atoms, -usually in a ratio of 1 : 2 : 1, -breakdown of sugars, such as glucose, supplies immediate energy for cell activities, -plants, some animals, and other organisms also use carbohydrates for structural purposes (like the strings in celery).

Simple Sugars -single sugar molecules are also known as monosaccharides or simple sugars. -includes glucose, galactose (component of milk), and fructose, (found in fruits). -ordinary table sugar, sucrose, is a disaccharide, or double sugar, a compound made by joining glucose and fructose together.

Complex Carbohydrates

Complex Carbohydrates -large macromolecules formed from monosaccharides are polysaccharides. -some plants like potatoes, store extra sugar as complex carbohydrates known as starches. -monomers in starch polymers are simple sugar molecules, such as glucose.

Complex Carbohydrates Plants also make another important polysaccharide called cellulose, which gives plants much of their strength and rigidity.

Complex Carbohydrates -Many animals store excess sugar in a polysaccharide called glycogen, -When your blood glucose gets low, glycogen is broken down into glucose, which is then released into the blood, -The glycogen stored in your muscles supplies the energy for muscle contraction.

Macromolecules Lipids can be used to -store energy, What are the functions of each of the four groups of macromolecules? Lipids can be used to -store energy, -be important parts of biological membranes and waterproof coverings.

Lipids -Large and varied group of biological molecules, -made mostly from carbon and hydrogen atoms, -generally not soluble in water, -include steroids synthesized by the body, -steroids, such as hormones, serve as chemical messengers, -not polymers and do not have monomers.

Lipids -Common categories of lipids are fats, oils, and waxes, -Fats usually solid at room temp and come from animals, -examples: butter and lard,

Lipids -Oils usually liquid at room temp and come from plants, -examples: olive oil and canola oil, -Waxes can come from both plants and animals, -examples: beeswax & the coverings of some vegetables such as cucumbers

Lipids Many lipids are formed when a glycerol molecule combines with compounds called fatty acids. Triglyceride -lipid composed of a glycerol molecule with three fatty acids attached, -fat that circulates in your blood.

Lipids Saturated fats -each carbon-carbon bond in a lipid’s fatty acid chains joined by a single bond. -animal fats

Lipids Unsaturated fats -at least one carbon-carbon double bond in a fatty acid. -plant oils Polyunsaturated fats -more than one carbon-carbon double bond.

Lipids Trans-fats -unsaturated oils that have had hydrogen whipped into them, -solid at room temp, -very unhealthy, -example: shortening

Lipids Lipids that contain unsaturated fatty acids, such as olive oil, tend to be liquid at room temperature. The data in the table illustrate how melting point decreases as the degree of unsaturation (number of double bonds) increases.

Macromolecules Nucleic acids What are the functions of each of the four groups of macromolecules? Nucleic acids -store and transmit hereditary, or genetic, information, -Examples: DNA, RNA

Nucleic Acids -macromolecules, -contain hydrogen, oxygen, nitrogen, carbon, and phosphorus, -polymers assembled from individual monomers known as nucleotides.

Nucleic Acids Nucleotides consist of three parts: -a 5-carbon sugar, -a phosphate group (–PO4), -a nitrogenous base. Some nucleotides, including adenosine triphosphate (ATP), play important roles in capturing and transferring chemical energy.

Nucleic Acids Two kinds of nucleic acids: -ribonucleic acid (RNA) -deoxyribonucleic acid (DNA). -RNA contains the sugar ribose -DNA contains the sugar deoxyribose. -Individual nucleotides joined by covalent bonds to form a polynucleotide, or nucleic acid.

Macromolecules Proteins can: -control the rate of reactions (enzymes), What are the functions of each of the four groups of macromolecules? Proteins can: -control the rate of reactions (enzymes), -regulate cell processes, -form important cellular structures, -transport substances into or out of cells (transport proteins), -help to fight disease (antibodies)

Protein -Proteins are macromolecules that contain: -nitrogen, -carbon, -hydrogen, and -oxygen, -monomers of proteins are called amino acids.

Protein Amino acids are compounds with -an amino group (–NH2) on one end and -a carboxyl group (–COOH) on the other end. Peptide bonds - covalent bonds that link amino acids together to form a polypeptide, -a molecule built from one or more polypeptides is a protein.

Structure and Function Amino acids -differ from each other in a side chain called the R-group, -have a range of different properties, -more than 20 different amino acids found in nature. -variety results in proteins being among the most diverse macromolecules.

Levels of Organization Proteins have four levels of structure: -Primary structure is the sequence of its amino acids. -Secondary structure is the folding or coiling of the polypeptide chain. -Tertiary structure is the complete, 3D arrangement of a polypeptide chain.

Levels of Organization Quaternary structure: -found in proteins with more than one chain -describes the way in which the different polypeptide chains are arranged with respect to each other. For example, hemoglobin, consists of four subunits.

To Sum Up Polymers Polymers are macromolecules that consist of many smaller parts called monomers. Carbohydrate polymers are: starches, glycogen, & cellulose. Carbohydrate monomers are: monosaccharides or simple sugars and include glucose, galactose, and fructose. Lipids are not polymers and do not have monomers.

To Sum Up Polymers Nucleic acid polymers are: RNA and DNA Nucleic acid monomers are: nucleotides and consist of a 5-carbon sugar, a phosphate group, and a nitrogen base. Protein polymers are: proteins such as hemoglobin Protein monomers are: amino acids that are linked to each other by peptide bonds to make polypeptides called proteins.

Section 2.3 Assessment (page 49) (a) What are the major elements of life? Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), and sulfur (S). Remember CHONPS! (b) What properties of carbon explain carbon’s ability to form different large and complex structures? Carbon atoms can bond to many other elements. They can also bond to other carbon atoms to form chains or rings. These bonds can be single, double, or triple bonds. This means that carbon atoms can be combined to make millions of different types of structures.

Section 2.3 Assessment (page 49) 2. (a) Name 4 groups of organic compounds found in living things. carbohydrates, lipids, nucleic acids, and proteins (b) Describe at least one function of each group of organic compounds. Carbohydrates: major source of energy for living cells Lipids: stored energy, insulation Nucleic acids: store and transmit hereditary information Proteins: control the rate of reactions, regulate cell processes

Section 2.3 Assessment (page 49) 2. (c) Why are proteins considered polymers but lipids are not? Proteins are polymers because they are made of chains of amino acids. Lipids are not polymers because they are not made of chains of smaller units. Lipids are made of a glycerol molecule combined with fatty acids. 3 (a) What atoms constitute the compound shown on page 49? (sucrose) carbon, hydrogen, and oxygen (b) What class of macromolecule does the compound belong to? carbohydrates