Chapter 3 Macromolecules

Objectives Distinguish between organic and inorganic compounds. Explain the importance of carbon bonding in biological molecules. Identify functional groups in biological molecules. Summarize how large carbon molecules are synthesized and broken down. Describe how the breaking down of ATP supplies energy to drive chemical reactions. Section 1 Carbon Compounds

Carbon Bonding Organic compounds contain CARBON (C) and are found in living things. Most inorganic compounds DO NOT contain carbon atoms. – Some that do: carbon dioxide (CO 2 ), cyanide (HCN) Which of the following do you think are organic? Which are inorganic? H2OH2O Na-Cl

Carbon Bonding Carbon atoms readily form four covalent bonds with other atoms (including carbon!) because it contains only four electrons in its outer energy level. These bonds allow carbon atoms to form a wide variety of simple and complex organic compounds with single, double, and triple bonds.

Carbon Bonding

Functional Groups Functional groups are groups of atoms that influence the properties of molecules and the chemical reactions they’re involved in. – Hydroxyl : rubbing alcohol Makes molecule polar Polar molecules are hydrophillic (soluble in water) – Carboxyl : formic acid – Amine : glycine – Phosphate : nucleic acid

Matching A.Phosphate B.Carboxyl C.Hydroxyl D.Amine

Large Carbon Molecules Condensation reactions join – Monomers (small simple molecules) into – Polymers (chains of molecules) aka “macromolecules” EX: carbs, lipids, proteins, and nucleic acids – A condensation reaction releases water as a by-product – In a hydrolysis reaction, water is used to split polymers into monomers Condensation Hydrolysis + H 2 O

Energy Currency Adenosine triphosphate (ATP) stores and releases energy during cell processes, enabling organisms to function.

Objectives Distinguish between monosaccharides, disaccharides, and polysaccharides Explain the relationship between amino acids and protein structure. Describe the induced fit model of enzyme action. Compare the structure and function of each of the different types of lipids. Compare the nucleic acids DNA and RNA. Section 2 Molecules of Life

Macromolecules Four main classes essential to life: 1.Carbohydrates 2.Proteins 3.Lipids 4.Nucleic Acids

1. Carbohydrates Carbohydrates are organic compounds composed of C, H, and O in about a 1:2:1 ratio Source of energy for organisms Structural materials in organisms Hydrophilic

1. Carbohydrates Carbohydrates are made up of monomers called monosaccharides (“one sugar”) EX: glucose, fructose, sucrose

1. Carbohydrates Two monosaccharides join to form a double sugar called a disaccharide (“two sugars”) – EX: fructose + glucose = sucrose A polysaccharide (“many sugars”) is made of three or more monosaccharides – EX: glycogen, starch, cellulose

2. Proteins Enzymes… Are essential for the functioning of any cell. Many of them are proteins speed up chemical reactions and bind to specific substrates. Enzyme reactions depend on the physical fit between the enzyme’s active site and the substrate (the reactant being catalyzed)

2. Proteins Proteins are organic compounds composed mainly of C, H, O, and N Hydrophilic Forms of proteins: – Enzymes – Most anti-bodies – Pigments – Hemoglobin – Hormones

2. Proteins Proteins are long chains of monomers called amino acids. The sequence of amino acids determines a protein’s shape and function. There are 20 common in plants and animals Two amino acids are joined by peptide bonds (covalent) to form a dipeptide (“two amino acids”) A long chain of amino acids is called a polypeptide (“many amino acids”).

2. Proteins Protein Structure

2. Proteins

Without enzymes, chemical reactions in the body would be too slow to support life Enzymes are used over and over If the environment changes, the enzyme might not work properly because the active site may change shape!

3. Lipids Lipids are large nonpolar molecules (don’t dissolve in water) Store the most energy (they have more C and H atoms) Important part of cell membranes Types of Lipids Triglycerides Phospholipids Steroids Waxes Pigments

3. Lipids Fatty Acids – The most abundant lipids contain fatty acids, unbranched carbon molecules with a hydrophilic end and a hydrophobic end. When none of the carbon atoms have double bonds, it is called saturated When any of the carbon atoms are double bonded, it is called unsaturated

3. Lipids Triglycerides – Triglycerides consist of 3 fatty acids and 1 molecules of glycerol. – Saturated triglycerides have saturated fatty acids, giving them high melting points so they are solid at room temp. Can you think of any examples?

3. Lipids Triglycerides – Unsaturated triglycerides have unsaturated fatty acids, so they are soft or liquid at room temp. – Usually found in plant seeds Can you think of any examples?

3. More Lipids Phospholipids consist of 2 fatty acids, 1 glycerol, and a phosphate group. – Make up the lipid bilayer of cell membranes

3. Even More Lipids Waxes – A wax is made up of one long fatty acid chain joined to one long alcohol – Waterproof Steroids – A steroid is composed of four fused carbon rings. – Hormones – Cholesterol Does anyone know any steroids?

4. Nucleic Acids A nucleic acid is a large, complex organic molecule that stores and transports information. – Made of N, C, H, O, P – Double helix structure – 2 types: Ribonucleic Acid (RNA) Deoxyribonucleic Acid (DNA)

4. Nucleic Acids DNA – DNA is a nucleic acid made of thousand of nucleotides (the monomers) – Contains the genetic information for cells – Humans have 46 molecules of DNA (or 46 chromosomes) – What makes up DNA? Sugar (deoxyribose) Phosphate group Base (adenine, thymine, cytosine, guanine)

4. Nucleic Acids DNA Animation Video!

4. Nucleic Acids RNA – RNA stores and transfers info from DNA to construct proteins – Can act as an enzyme