Biochemistry

1. Biochemistry Atoms, Elements, and Compounds Chemical Reactions Water and Solutions The Building Blocks of Life

2. Review • Atoms are the building blocks of matter. • Protons- positively charged particles • Neutrons- have no charge • Protons and neutrons are located in the nucleus of the atom • Electrons- negatively charged particles • Move around the nucleus in energy levels

3. Elements • An elementis a pure substance that cannot be broken down into other substances by physical or chemical means. • Isotopes- atoms of the same element that have the same number of protons and electrons but have a different number of neutrons • Compounds-apure substance formed when two or more different elements combine

4. Chemical Bonds • The forming of chemical bonds stores energy and the breaking of chemical bonds releases energy for an organism’s life processes (growth development, reproduction) • Covalent bonds-chemical bond that forms when electrons are shared • Compounds that held together by covalent bonds are called molecules

5. Ionic bond- an electrical attraction between two oppositely charged atoms or groups of atoms • van der Waals Forces- When molecules come close together, the attractive forces between slightly positive and negative regions pull on the molecules and hold them together (water)

6. Chemical Reactions • The process by which atoms or groups of atoms in substances are reorganized into different substances • Chemical bonds are broken and formed • Production of heat or light, and formation of a gas, liquid, or solid • Reactants- starting substances • Products- substances formed during reaction

7. Energy of Reactions • Activation energy- the minimum amount of energy needed for reactants to form products in a chemical reaction • This reaction is exothermic and released heat energy.

8. Energy of Reactions • This reaction is endothermic and absorbed heat energy.

9. Enzymes • Catalyst- a substance that lowers the activation energy needed to start a chemical reaction • Enzymes- biological catalysts • Not used up in the reaction • pH and temperature affect enzyme activity

10. Enzymes • Substrates- the reactants that bind to the enzyme • Active site- the specific location where a substrate binds on an enzyme

11. Water’s Polarity • Molecules that have an unequal distribution of charges are called polar molecules • Hydrogen bond- aweak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom

12. Mixtures • Solution (homogenous mixture)- has the same composition throughout • Solvent- a substance in which another substance is dissolved. • Solute- the substance that is dissolved in the solvent • Heterogeneous- the parts remain distinct, can identify individual parts

13. Acids Bases Substances that release hydroxide ions (OH–) when dissolved in water The more OH–released the more basic the solution Basic solutions have pH values higher than 7 Buffer- mixtures that can react with acids or bases to keep the pH within a particular range • Substances that release hydrogen ions (H+) when dissolved in water • The more H+ released the more acidic the solution • pH- the measure of concentration of H+ in a solution • Acidic solutions have pH values lower than 7.

14. Organic Chemistry • The study of organic compounds • Almost all biological molecules contain the element carbon. • Macromolecules- large molecules formed by joining smaller organic molecules together • Polymers- molecules made from repeating units of identical or nearly identical compounds linked together by a series of covalent bonds

15. Carbon • Has four electrons in its outermost energy level. • One carbon atom can form four covalent bonds with other atoms. • Carbon compounds can be in the shape of straight chains, branched chains, and rings.

16. Carbohydrates • Compounds composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom—(CH2O)n • Monosaccharides- short chains of carbohydrates (simple sugars) • Disaccharides- two monosaccharides linked together • Polysaccharides- longer carbohydrate chains

17. Carbohydrates • Energy sources for organisms • Provide structural support in cell walls of plants and in the hard shells of shrimp, lobsters and some insects

18. Lipids • Molecules made mostly of carbon and hydrogen • Fats, oils, waxes • Main function: to store energy • Triglyceride- fat when solid, oil when liquid

19. Saturated fats- carbon atoms cannot bond with any more hydrogen atoms • Unsaturated- carbon atoms can bond with more hydrogen atoms • Phospholipids- fats with more than one double bond in the tail • Responsible for structure and function in cell membrane • Steroids- (cholesterol and hormones) provides starting point for other important lipids, estrogen and testosterone

20. Proteins • Made of small carbon compounds called amino acids • Amino acids- small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur. • 20 different amino acids • Proteins are made of different combinations of amino acids joined together by peptide bonds

21. Protein: Structure • Amino acid chains fold into three-dimensional shape • A protein might contain many helices, pleats, and folds, held by hydrogen bonds

22. Protein: Function • Provide structural support • Transport substances inside and between cells • Communicate signals within the cell and between cells • Speed up reactions • Control cell growth

23. Nucleic Acids • Complex macromolecules that store and transmit genetic information • Nucleotides- repeating subunits that make up nucleic acids • Carbon, nitrogen, oxygen, phosphorus, and hydrogen • 3 units: a phosphate, a nitrogenous base, and a sugar

25. Nucleic Acids • 2 types found in living things • Deoxyribonucleic acid (DNA) • Ribonucleic acid (RNA) • DNA = “genetic code” • Stores all the information to grow, reproduce, and adapt • RNA uses the information stored in DNA to make protein