Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings BIO Biochemistry

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Composition of Matter  The “stuff” of the universe  Anything that has mass and takes up space  Made of elements

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Elements – Unique substances that cannot be broken down into simpler substances by chemical methods.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings What 4 elements make up 96% of the body?

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Atoms – Building blocks of elements Every element’s atoms differ from all other elements. Differences in atoms give each element different physical and chemical properties.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Atomic Structure Atoms are made of subatomic particles

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 2 electrons2 protons Charges balanced In an uncharged atom, the number of _______ and the number of _______ are _______ He

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Molecules and Compounds Molecule- A combination of 2 or more atoms held together by chemical bonds. The atoms can be the same (H 2 ) or different (H 2 O). Compound- A type of molecule formed by a combination of 2 or more different kinds of atoms like H 2 O.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings is a water molecule. Water is a compound. is a hydrogen gas molecule. Hydrogen gas is not a compound. All compounds are made of molecules, but not all molecules are compounds.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Chemical Bonds Electron shells, or energy levels, surround the nucleus of an atom.  Bonds are formed using the electrons in the outermost energy level.  Each energy level can hold a specific number of electrons.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Filling Electron Shells  Valence shell – Outermost electron energy level  Octet rule – Except for the first shell which is full with two electrons, atoms interact in a manner to have 8 electrons in their valence shell (energy level) Will this atom interact with others? What about this one?

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Types of Bonds Ions- Charged atoms resulting from the gain or loss of electrons. Ionic bonds form between atoms by the transfer of one or more electrons

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings

Covalent Bonds  Covalent bonds are formed by the sharing of two or more electrons.  Electron sharing produces molecules.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Hydrogen Bonds  More like attractions than bonds  Formed when a hydrogen atom (which is already covalently bonded to an atom) is attracted to another atom  Causes surface tension in water

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Hydrogen Bonds in Water Figure 2.10a

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Organic Chemistry  Molecules containing carbon  Exception- CO, CO 2 & HCO 3 - because they are smaller, less complex molecules  Carbon is special because it is electroneutral- never loses nor gains electrons but always shares electrons  Building blocks of cells  They include carbohydrates, lipids, proteins and nucleic acids They include carbohydrates, lipids, proteins and nucleic acids

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrates: Sugars and Starches Contain carbon, hydrogen, and oxygen in a 1:2:1 ratio Monosaccharides: Simple sugars (glucose) Disaccharides: Double sugars- 2 monosaccharides bonded together (sucrose) Polysaccharides: Many sugars- Polymer of monosaccharides (starch)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Major functions of carbs  Used by cells to make ATP (cell energy)  Extra carbs are stored in muscles and the liver as glycogen  Cell identity markers

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Lipids  Also contain C, H, and O but contains less O than carbs  Functions include:  Organ padding  Energy storage  Provide structure to the cell membranes  Sex hormones

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Proteins  Large molecules composed of combinations of 20 different amino acids.  Functions include:  Hormones  Antibodies  Cell membrane structure  Muscle structure  Enzymes  Characteristics (hair color, skin color, eye color)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins  Primary – Linear- Amino acid sequence  Secondary – Twisted or bent primary structure

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Structural Levels of Proteins  Tertiary – superimposed folding of secondary structures  Quaternary – Two or more protein chains linked together in a specific manner

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Enzymes  Proteins that act as biological catalysts (speed up reactions) by lowering the energy needed for a chemical reaction (activation energy)  Usually end in –ase  Act on a substance called a substrate

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Mechanism of Enzyme Action  Substrate binds to the enzyme at its active site. The enzyme and substrate fit together like a lock and key.  The enzyme-substrate complex undergoes internal rearrangements that form the product(s).  The enzyme releases the product(s).  Enzyme is unchanged so it can act over and over again.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 2.21 Active site Amino acids Enzyme (E) Enzyme-substrate complex (E-S) Internal rearrangements leading to catalysis Dipeptide product (P) Free enzyme (E) Substrates (S) Peptide bond H2OH2O +

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Nucleic Acids  Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus  Examples:  DNA  RNA  ATP

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings DNA  Genetic code: Tells the cells what proteins to make and when to make them.  Found inside the nucleus.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings RNA  Complementary copy of the DNA code.  Made in the nucleus and exits to the cytoplasm.  Used as instructions for building proteins.

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Transcription and Translation Transcription= Making RNA from DNA Translation= Making proteins from RNA