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Transcript
STRENGTH “Do not pray for easy lives. Pray to be stronger men! Do not pray for tasks equal to your powers. Pray for power equal to your tasks." -Phillips Brooks CHAPTER 2 The Chemical basis of Life Matter • Anything that occupies space and has mass. • Can exist as: • ____________ • ____________ • ____________ • composed of elements • What are examples of each type of matter? What is an element? • Element- substances that can not be separated into smaller substances by natural means. • 92 of the 112 occur in nature • 2 additional elements are hypothetical (114, 116) • And 2 more are not known to exist (113, 115) • Are referred to by a chemical symbol and are organized in the Periodic Table of Elements. Elements in Animal Body • Major Elements- make up 96% of the body • ___________(O) • ___________(C) • ___________ (H) • ___________ (N) Minor Elements • _______________ (Ca) • _______________(P) • _______________ (K) • _______________(S) • _______________(Na) • _______________ (Cl) • ________________ (Mg) Trace Elements • • • • • • • • • • • • • • • Silicone (Si) Aluminum (Al) Iron (Fe) Manganese (Mn) Fluorine (F) Vanadium (V) Chromium (Cr) Copper (Cu) Boron (B) Cobalt (Co) Zinc (Zn) Selenium (Se) Molybdenum (Mo) Tin (Sn) Iodine (I) Atoms • The smallest unit of an element that retains the unique properties of that element. • Composed of 3 subatomic particles: • ___________ • ___________ • ___________ Protons, Neutrons, & Electrons • • Protons and Neutrons are found in the _____________________. Each proton and neutron has an atomic mass of ~1. • • • • • Together protons and neutrons determine the __________________of the atom. Protons have a _______________ charge. Neutrons have ______________charge and are considered neutral. Electrons have a _____________ charge. Net charge of atoms are neutral because have equal numbers of protons and electrons. Electrons • Tiny particles that remain in constant motion around the nucleus. • So tiny that their mass does not contribute to the atomic weight of the atom. • Electrons have a ________________ charge. • Orbit around nucleus Electron Shells and how they work • “Pathways” around the nucleus where electrons orbit • Only a certain number of electrons can be on each path at one time • If the outermost shell is not full, then an atom will be more active in an attempt to fill its outermost shell. • Helium and Neon have full electron shells so are considered chemically ___________. How the Shells work • First shell can contain ________ electrons. • Second shell on can contain _________ electrons. Atoms continued • The atomic number of an atom tells us how many ____________ and ____________ it has. • If an atom loses or gains an electron in an attempt to fill its outermost electron shell then it becomes positively or negatively charged, thereby becoming an _______________. • If an atom has a different number of neutrons, they are called ______________________ of the element Atomic Number Isotopes Ions e- Na atom Na+ ion 11electrons, 11protons 10electrons, 11protons Molecules and Compounds • ___________________- when atoms are joined together by chemical bonds. These are the smallest particle of a substance that retains the properties of the substance. • _____________________when two or more atoms of the same element are joined together. • _______________- how atoms are attached to one another. • ________________ A substance made up of two or more elements. Chemical Bonds • Means that the atoms are sharing or transferring electrons between them. • By sharing or giving away electron, each atom can be sure that its outermost shell is full. • Remember that atoms are constantly trying to become more stable. • Types of chemical bonds: • _________________ • _________________ • _________________ Covalent Bonds • Bonds formed when atoms share electrons. • Classified depending on how many electrons are being shared. • single covalent bond — ______ electron is shared • double covalent bond — _____ electrons are shared • triple covalent bond — ______ electrons are shared • May be shared equally (nonpolar) or unequally (polar). Polar Water Molecule • Shared electrons in a covalently bonded molecule may spend more time near one atom than the other • Shared electrons in water molecule spend more time near __________atom than __________ atoms • Created ‘poles’ • Gives molecule a slight _________ charge on H side of molecule and slight _________charge on O side of molecule http://www.youtube.com/watch?v=qmgE0w6E6ZI Ionic Bonds • Formed when electrons are transferred from one atom to another. • Transfer causes a ______ charge on the atom that gave up the electron and a ____________ charge on the atom that receives the electron. • Since opposites attract, the two atoms stick together through electrostatic attraction. Electron transferred Attraction between opposite charges Types of Ions • ______________- Ions with a net positive charge. • _______________Ions with a net negative charge. • Ions are important in contraction of muscle fibers, transmission of nerve impulses, and maintenance of water balance. Hydrogen Bonds • Bond between hydrogen atoms already covalently bonded in a molecule to oppositely charged particles. • Found between water molecules and DNA to stabilize shape. Chemical Reactions • The formation and breaking of chemical bonds. • Require energy input or release of energy. • Chemical Equation- reaction is described in written form. • X+Y → Z • (reactants) (products) • Arrow indicates direction of the reaction Types of Chemical Reactions • 1. Synthesis Reaction- new and more complex molecule is made from simpler chemicals. Example: • 2. Decomposition Reaction- single complex chemical is broken down into multiple, simpler, chemicals. Example: • 3. Exchange Reaction- certain atoms are exchanged between molecules. Combination of synthesis and decomposition reaction. Example: Chemical Reactions Continued • _____________ reactions require energy. • ______________ reactions expend or release energy. • _______________have no net energy requirements. Energy released from decomposition portion, helps with synthesis portion. Chemical Reactions Continued • Factors that influence reaction rates • ________________________ • ________________________ • __________________-the energy required for the reaction to happen. • Some reactions require presence of a catalyst or enzyme • Reaction speed is increased when catalyst is present • Protein (enzyme) Chemical Components of Living Organisms: Organic and Inorganic Compounds • Inorganic compounds- do not contain hydrocarbon groups (H and C bonded together) and often have ionic bonding. • Water • Salts • Acids and Bases • Organic compounds- contain hydrocarbon groups and are usually covalently bonded Why is water so Important? • Water is the universal _______________ • ______________- chemicals added to water • _______________- resulting chemical and water mixture • ________________ (water loving)- chemicals that dissolve well or mix with water. • _________________(water hating)- chemicals or molecules that do not mix well with water. • Water is an ideal ______________________ • Blanketing power allows molecules in water to move around and be cushioned from one another. • Blood • Urine • Water has a _______________and a high _______________________________ • Easily able to absorb heat. • Won’t evaporate easily. • Water is used for ________________. Salts • Mineral compounds that have ionic bonds • In ionic form are called electrolytessubstances that have ability to transmit an electrical charge. Acids and Bases • ___________- substances that when added to water freely release hydrogen ions. • Called H donors or proton donors • ___________- alkaline in nature release a hydroxyl ion (OH-) when added to water. • Called proton acceptors • Acids and Bases are also electrolytes as they can transmit electricity when ionized in water. The pH Scale • Ranges from 1-14. • Lower numbers are the most acidic, higher numbers are more alkaline. Buffers • A substance that minimizes the change of the acidity of a solution when an acid or base is added to the solution. • By not allowing excessive hydrogen or hydroxyl ions to accumulate, buffers help cell maintain _______________. Organic Molecules • • Molecules that contain carbon. • Why carbon?-4 outer electrons in outer shell, trying to share this to complete outer shell. Divided into 4 groups: • _____________________ • Glycogen • Ribose • ____________________ • Triglycerides • Phospholipids • Steroids • Prostaglandins • _____________________ • Globular • Fibrous • _____________________ • DNA • RNA • Adenosine triphosphate (ATP) Carbohydrates • Used for energy, storage of energy, and cellular structures. • Simple Sugars-________________. • Glucose and Fructose • ________________- when two monosaccharides are joined together in synthesis reaction. • _________________- combinations of many monosaccharides. • Glycogen and cellulose Some terminology • _________________- when a macromolecule is formed out of a carbohydrate attached to a protein. • __________________- process of building molecules needed for cellular functioning. • _____________________- Decomposition of nutrients. Lipids • Used for energy and stored in fat. • 4 classes of Lipids: • _________________ • _________________ • _________________ • _________________ Lipids continued.. • Neutral Fats • Also called triglycerides or fats. • Contains three fatty acids and a glycerol molecule. • _________________________- all bonds in the hydrocarbon chain are single bonds. • _________________________- when there are some double bonds between the carbon and hydrogen atoms. • __________________________macromolecule composed of proteins and lipids • __________________________- when triglycerides are decomposed. • Phospholipids • Have a glycerol backbone • Have a lipid bilayer when placed in water. • ________________ heads are facing water, while _______________ tails line up with one another. • Steroids • Take form of four interlocking hydrocarbon rings. • Are hydrophobic. • Examples include: • Cholesterol • Cortisol • Eicosanoids • Lipids formed from a 20 carbon fatty acid and ring structure. (hairpin structure) • Include: • _______________- in inflammation • _______________- platelet function • _______________bronchoconstriction and increased mucus production. Proteins • Most abundant organic molecules in the body. • Have widest variety of functions. • Catalyze- speed up reactions occurring in the body. • Composed of ___________________ Amino Acids • • • 20 different amino acids used by the body. Central carbon is attached to hydrogen atom, an amino group (NH2), a carboxyl group (COOH), and a side chain. Include: Alanine Arginine Asparagine Aspartic acid Cysteine Glutamic acid Glutamine Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tryptophan Tyrosine Valine Structure of Proteins • Shape of protein directly determines its function. • Antibodies- fit together like puzzle to foreign invaders. • Structure is described in four layers: • ____________________- sequence and number of amino acids that link together to form the peptide chain. • Secondary Structure- the natural bend of parts of the peptide chain as it is formed in three dimensions. • Tertiary Structure- overall shape of a single protein molecule. • Quaternary Structure- when two or more protein chains join to form a complex macromolecule. • http://www.youtube.com/watch?v=Oz2x_y xPXww&feature=related Structural Proteins • Stable, rigid, water-insoluble proteins that are used for adding strength to tissues or cells. • Aka Fibrous proteins. • Important in structural framework and physical movement. • Examples include: • _______________ • _______________ • _______________ Functional Proteins • Aka Globular proteins. • Function in chemical reactions, transport of molecules, regulation of metabolism, and immune system. • Include: • Hormones • Antibodies • Protein-based hormones • Enzymes Enzymes • Proteins that ___________ or speed up chemical reactions. • Will end in –ase • ______________ – the substance that the enzyme acts upon. Nucleic Acids • Largest molecule of body • 2 classes of Nucleic Acids • _______________________________ • Exists mainly in the nucleus but also mitochondria. • Contains all instructions needed by cell to build proteins. • Coded in segments called __________ • _______________________________ • Transfers the instructions out of the nucleus and into the cytoplasm and builds proteins. • Exists as mRNA, tRNA, and rRNA. Nucleotides • The molecular building blocks of nucleic acids. • Are 5 different nucleotides, but all have the same structure. • Are all composed of a 5-Carbon pentose sugar. • Sugar in DNA is _____________. • Sugar in RNA is _____________. • Nucleotides are named for their nitrogen base. • A,C,T,G,U Structure of a nucleotide Nucleotides • • • • • A___________-both DNA and RNA G___________-both DNA and RNA C___________-both DNA and RNA T___________-Only in DNA U___________- Only in RNA Nucleic Acids • Information needed to produce proteins is based on order of the nucleotides in DNA and RNA. • C-G-T makes amino acid alanine. • ___________________-long chains of genes combined with proteins. DNA • Consists of two parallel strands of nucleotides adenine, guanine, cytosine and thymine. • Connected by hydrogen bonds between specific pairings of nucleotides. • Adenine and __________ • __________ and Cytosine • Once bound, these two strands twist around one another to form a ______________. • Order of nucleotides is what makes unique genetic code of each individual. Structure of DNA RNA • Consists of only one strand of nucleotides. • Does not have thymine, but instead has uracil. • Pairings are: • Guanine and Cytosine • Adenine and __________ • Exists in three forms: • tRNA- _________RNA • Copies information in the DNA molecule • mRNA- __________RNA • Carries information out of the nucleus • rRNA-___________ RNA • Creates the proteins needed by the body ATP • ____________________- energy of the cells. • Cells need ATP to fuel or carry out any work. • _____________________when the cells use up the nutrients • ATP is a RNA nucleotide containing adenine with two additional phosphate groups attached. • When bonds (high energy bonds) between phosphate groups are broken, energy is released. • When phosphate group is lost, resulting molecule is adenosine diphosphate (ADP). Why is it so important? • Since we know how these bonds work, we can understand how certain things such as drugs and chemical reactions in the body occur. • Will help us later on in digestion of food, growth of the body, cellular signaling, and transmission of nerve impulses.