1. 2.3 Carbon-Based Molecules KEY CONCEPT Carbon-based molecules are the foundation of life.

2. 2.3 Carbon-Based Molecules Carbon atoms have unique bonding properties. Carbon forms covalent bonds with up to four other atoms, including other carbon atoms. Carbon-based molecules have three general types of structures. –straight chain –branched chain –ring

3. 2.3 Carbon-Based Molecules Many carbon-based molecules are made of many small subunits bonded together. –Monomers are the individual subunits. –Polymers are made of many monomers.

4. 2.3 Carbon-Based Molecules Integrating Chemistry – Types of reactions Some polymers form through a process of dehydration, that is, a molecule of water is released as one or more monomer bonds to another. One provides a hydrogen (H) and the other provides a hydroxyl group (OH). Some polymers can also be broken down in a reverse reaction called hydrolysis. The bonds between the monomers are broken by the addition of water molecules (H2O).

5. 2.3 Carbon-Based Molecules Four main types of carbon-based molecules are found in living things. Carbohydrates are made of carbon, hydrogen, and oxygen. –C, H and O are combined in a ratio of 1:2:1

6. 2.3 Carbon-Based Molecules Four main types of carbon-based molecules are found in living things. 1. Carbohydrates are made of carbon, hydrogen, and oxygen. –Carbohydrates include sugars and starches. –Monosaccharides are simple sugars like glucose and fructose. –Disaccharides include sucrose, maltose and lactose –Polysaccharides include starches, cellulose, and glycogen.

7. 2.3 Carbon-Based Molecules Carbohydrates can be broken down to provide energy for cells (starch and glycogen). Glycogen is made by animals and stored in their liver. Some carbohydrates are part of cell structure (cellulose). Polymer (starch) Starch is a polymer of glucose monomers that often has a branched structure. Starch is made and stored by plants. They break it down for energy. Polymer (cellulose) Cellulose is a polymer of glucose monomers that has a straight, rigid structure. It is used and the building block of plant cell structure. It is the tough outer covering of plant cells. monomer

8. 2.3 Carbon-Based Molecules –Many contain carbon chains called fatty acids. –Fats and oils contain fatty acids bonded to glycerol. 2. Lipids are nonpolar molecules that include fats, oils, and cholesterol. Triglyceride

9. 2.3 Carbon-Based Molecules Lipids have several different functions. –broken down as a source of energy (fats and oils) –make up cell membranes (phospholipids and cholesterol) – used to make hormones (cholesterol makes steroid hormones like testosterone and estrogen)

10. 2.3 Carbon-Based Molecules Fats and oils have different types of fatty acids. –saturated fatty acids (common in animal fats) –unsaturated fatty acids

11. 2.3 Carbon-Based Molecules Phospholipids make up all cell membranes. –Polar phosphate “head” –Nonpolar fatty acid “tails” Phospholipid How would the polar head of a phospholipid respond to water molecules? How would the nonpolar tails respond to water molecules?

12. 2.3 Carbon-Based Molecules 3. Proteins are polymers of amino acid monomers. –Twenty different amino acids are used to build proteins in organisms. –They are the most varied of the carbon-based molecules and function in movement, eyesight or digestions and many other things. Fig. Serine is one of 20 amino acids that make up proteins in organisms

13. 2.3 Carbon-Based Molecules –Amino acids differ in side groups, or R groups. Proteins are polymers of amino acid monomers. –Twenty different amino acids are used to build proteins in organisms.

14. 2.3 Carbon-Based Molecules –Amino acids are linked by peptide bonds. Proteins are polymers of amino acid monomers. –Amino acids differ in side groups, or R groups. –Twenty different amino acids are used to build proteins in organisms.

15. 2.3 Carbon-Based Molecules Proteins differ in the number and order of amino acids. –Amino acids interact to give a protein its shape. Primary structure (amino acid chain), secondary structure (folds, alpha or beta), tertiary structure (overall shape). –Incorrect amino acids change a protein’s structure and function. hydrogen bond Hemoglobin

16. 2.3 Carbon-Based Molecules Hemoglobin and Sickle Cell Anemia Hemoglobin in red blood cells transports oxygen. Just one amino acid change causes red blood cells to have the curved shape characteristic of sickle cell anemia. (colored SEM; magnification 3500 X)

17. 2.3 Carbon-Based Molecules 4. Nucleic acids are polymers of monomers called nucleotides. They carry detailed instructions to build proteins.

18. 2.3 Carbon-Based Molecules –Nucleotides are made of a sugar, phosphate group, and a nitrogen base. A phosphate group nitrogen-containing molecule, called a base deoxyribose (sugar) Nucleic acids are polymers of monomers called nucleotides.

19. 2.3 Carbon-Based Molecules –DNA stores genetic information. Nucleic acids are polymers of monomers called nucleotides. –Nucleotides are made of a sugar, phosphate group, and a nitrogen base. –RNA builds proteins. DNA RNA Apply: What is the relationship between proteins and nucleic acids?