8/18/2016 What happens when milk sours or a tree Microbes rots? Microbes are conducting chemical reactions Bacteria decompose the wood Bacteria produce lactic acid that sours the milk Invisible Invaders Amazing Allies Knowledge of chemistry is vital to understand: what roles microorganisms play in nature how microbes cause disease how to develop diagnostic methods to detect disease how the body wards off infection Chapter 2 how antibiotics and vaccine are produced Chemical Principles changes that occur in microbes changes that microbes make in our environment Atoms:Basic Building Blocks of all Types Structure of Atoms Matter All atoms have a nucleus and Matter-all materials that occupy space and electrons that move around the e have mass nucleus ●Atoms are composed of Matter is composed of atoms protons-positively(+)charged particles Atom-simplest component of pure neutrons-neutral uncharged particles substance that is not divisible into simpler electrons-negatively(-)charged particles substances Charge is a property of particles that produce a repulsive or Atoms interact with each other to form attractive force molecules Chemical element-all atoms with the same number of nave the e way chemically Chemistry is the science of the interaction between atoms and molecules If the outer most shell is partially filled,the atom is unstable and can react with other atoms
8/18/2016 1 Invisible Invaders Amazing Allies Chapter 2 Chemical Principles What happens when milk sours or a tree rots? Microbes are conducting chemical reactions Bacteria decompose the wood Bacteria produce lactic acid that sours the milk Knowledge of chemistry is vital to understand: what roles microorganisms play in nature how microbes cause disease how to develop diagnostic methods to detect disease how the body wards off infection how antibiotics and vaccine are produced changes that occur in microbes changes that microbes make in our environment Matter - all materials that occupy space and have mass Matter is composed of atoms Atom – simplest component of pure substance that is not divisible into simpler substances Atoms interact with each other to form molecules Chemistry is the science of the interaction between atoms and molecules Atoms: Basic Building Blocks of all Types Matter All atoms have a nucleus and electrons that move around the nucleus Atoms are composed of protons – positively (+) charged particles neutrons – neutral uncharged particles electrons - negatively (-) charged particles Charge is a property of particles that produce a repulsive or attractive force Chemical element – all atoms with the same number of protons that behave the same way chemically Outermost electron shell can give up or accept electrons from other atoms If the outer most shell is partially filled, the atom is unstable and can react with other atoms. Structure of Atoms
8/18/2016 Chemical Bonds Three Types of Chemical Bonds he compironfe me Atoms are electrically neutral when positive ination of two or more atoms-the same charges equal negative charges eg3a8r-earatgtg2otleast2or An ion is a negatively or positively charged atom resulting from the loss or gain of electrons cmpounds are molecules but not all molecules ae 1.Covalent bonds-electrons are shared among atoms Chemical bonds-when 2 or more atoms share,donate molecules and compounds: polar covalent bonds-unequal sharing attractive forces are formed nonpolar covalent bonds-equal sharing 3 types of chemical bonds covalent 回●)→⊙●) ionic hydrogen a0 回可 Three Types of Chemical Bonds Three Types of Chemical Reactions 2.Ionic bonds-electrons are transferred to Synthesis Reactions (anabolism) one atom forming positively charged cations Two or more molecules combine to form a larger molecule and negatively charged anions-formed by A+B -AB attraction sugar molecules to form starch 3.Hydrogen bonds-weak electrostatic bonds amino acids to form protein between hydrogen and other atoms,O and N Decomposition Reactions (catabolism) Split larger molecules into smaller parts AB-A+B bonds are broken breakdown of sucrose into fructose and glucose Exchange Reactions Part synthesis and part decomposition Bonds are broken between two molecules and new bonds are formed to synthesize new molecules AB +CD ->AD BC 2
8/18/2016 2 Molecule – distinct chemical substance that results from the combination of two or more atoms - the same or different atoms - oxygen Compounds – a molecule that contains at least 2 or more different atoms, such as water All compounds are molecules but not all molecules are compounds Chemical bonds – when 2 or more atoms share, donate or accept electrons to form molecules and compounds; attractive forces are formed 3 types of chemical bonds covalent ionic hydrogen Chemical Bonds Atoms are electrically neutral when positive charges equal negative charges An ion is a negatively or positively charged atom resulting from the loss or gain of electrons 1. Covalent bonds – electrons are shared among atoms polar covalent bonds– unequal sharing nonpolar covalent bonds– equal sharing Three Types of Chemical Bonds Covalent bond 2. Ionic bonds – electrons are transferred to one atom forming positively charged cations and negatively charged anions – formed by attraction 3. Hydrogen bonds – weak electrostatic bonds between hydrogen and other atoms, O and N Three Types of Chemical Bonds Ionic bond Synthesis Reactions (anabolism) Two or more molecules combine to form a larger molecule A + B AB sugar molecules to form starch amino acids to form protein Decomposition Reactions (catabolism) Split larger molecules into smaller parts AB A + B bonds are broken breakdown of sucrose into fructose and glucose Exchange Reactions Part synthesis and part decomposition Bonds are broken between two molecules and new bonds are formed to synthesize new molecules AB + CD AD + BC Three Types of Chemical Reactions
8/18/2016 Important Biological Molecules Inorganic Compounds Inorganic Compounds Small and structurally simple Learning Objectives Typically lack carbon Examples:water,oxygen,carbon dioxide,salts, List several properties of water that are acids,and bases important to living systems Define acid,base,salt,and pH Organic Compounds Always contain carbon and hydroger Examples:structurally complex polysaccharides, proteins,and nucleic acids(macromolecules) Water Water is a Good Medium for Living Cells All living organisms require a variety of Exists mostly as liguid on Earth inorganic compounds for growth,repair, -strong attraction for other water molecules maintenance,and reproduction requires heat to form vapor == Water is vital and makes up on average 65%- Good solvent(dissolving medium)due to 75%of every cell polarity For microorganisms,outside the cell nutrients polar substances dissociate forming solutes are dissolved in water,which aids their passage into the cell Key reactant in the digestive process and in the synthesis of organic compounds in cells Water is a polar molecule since it -H'and O participate in chemical reactions has a slight negative and a Maintains a constant temperatur slight positive charge H a good temperature buffer for living cells Polar molecule Due to the H-bond of water molecules
8/18/2016 3 Inorganic Compounds Small and structurally simple Typically lack carbon Examples: water, oxygen, carbon dioxide, salts, acids, and bases Organic Compounds Always contain carbon and hydrogen Examples: structurally complex polysaccharides, proteins, and nucleic acids (macromolecules) Important Biological Molecules Learning Objectives List several properties of water that are important to living systems Define acid, base, salt, and pH Inorganic Compounds All living organisms require a variety of inorganic compounds for growth, repair, maintenance, and reproduction Water is vital and makes up on average 65%- 75% of every cell For microorganisms, outside the cell nutrients are dissolved in water, which aids their passage into the cell Water is a polar molecule since it has a slight negative and a slight positive charge Water Polar molecule Water is a Good Medium for Living Cells Exists mostly as liquid on Earth - strong attraction for other water molecules - requires heat to form vapor Good solvent (dissolving medium) due to polarity - polar substances dissociate forming solutes Key reactant in the digestive process and in the synthesis of organic compounds in cells - H+ and O- participate in chemical reactions Maintains a constant temperature providing a good temperature buffer for living cells - Due to the H-bond of water molecules Water acts as a solvent for sodium chloride
8/18/2016 Acids Acids,Bases,and Salts An acid is a substance that When inorganic salts are dissolved in dissociates into one or more water,they undergo ionization or hydrogen(H)ion dissociation. They break apart into ions. An ion is a negatively or positively HCI→H+C charged atom. (a)Acid An acid can be defined as a In water. proton(H)donor hydrochloric acid (HCI)dissociates into hydrogen and chloride ions Bases Salts A base is a substance that ●A salt is a substance that dissociates into NaOH->Na'+OH- cations and anions, neither of which is H'or oH-. A hydroxide ion(OH-)car combine with protons and is a proton (H)acceptor In water. .sodium NaCl→Na*+CH (e)Sait hydroxide (NaOH) dissociates into In water,sodium chloride hydroxide and (NaCl)dissociates into sodium ions chloride and sodium ions 4
8/18/2016 4 Acids, Bases, and Salts • When inorganic salts are dissolved in water, they undergo ionization or dissociation. • They break apart into ions. • An ion is a negatively or positively charged atom. An acid is a substance that dissociates into one or more hydrogen (H+) ion HCl H+ + Cl An acid can be defined as a proton (H+) donor Acids In water, hydrochloric acid (HCl) dissociates into hydrogen and chloride ions Bases In water, sodium hydroxide (NaOH) dissociates into hydroxide and sodium ions A base is a substance that dissociates into one or more hydroxide ion (OH) NaOH Na+ + OH A hydroxide ion (OH-) can combine with protons and is a proton (H+) acceptor A salt is a substance that dissociates into cations and anions, neither of which is H+ or OH. NaCl Na+ + Cl Salts In water, sodium chloride (NaCl) dissociates into chloride and sodium ions
8/18/2016 Acid-Base Balance:the Concept of pH The amount of Hin a solution is expressed as pH(potential of hydrogen) Increasing [H+],increases acidity Increasing [OH-]increases alkalinity Most organisms grow best between pH 6.5-8.5 H'1IOM Too high or too low pH.enzymes change in shape cannot promote chemical reactions in a cell Chemical reactions in a cell are sensitive to pH Most biochemical processes in a cell involve OH- and Hions Organic Compounds Structure and Chemistry Learning Objectives Inorganic compounds,excluding water, Distinguish organic and inorganic compounds constitute 1%-1.5%of cells Identify the building blocks of carbohydrates Organic molecules,whose carbon atoms Differentiate simple lipids,complex lipids, can combine in many ways with carbon and steroids atoms of other elements,are complex and Identify the building blocks and structure of can perform complex biological functions proteins Small organic molecules can combine into large macromolecules Identify the building blocks of nucleic acids Describe the role of ATP in cellular reactions 5
8/18/2016 5 Acid-Base Balance: the Concept of pH The amount of H+ in a solution is expressed as pH (potential of hydrogen) Increasing [H+], increases acidity Increasing [OH] increases alkalinity Most organisms grow best between pH 6.5 - 8.5 Too high or too low pH, enzymes change in shape cannot promote chemical reactions in a cell Chemical reactions in a cell are sensitive to pH Most biochemical processes in a cell involve OH and H+ ions Learning Objectives Distinguish organic and inorganic compounds Identify the building blocks of carbohydrates Differentiate simple lipids, complex lipids, and steroids Identify the building blocks and structure of proteins Identify the building blocks of nucleic acids Describe the role of ATP in cellular reactions Organic Compounds Structure and Chemistry Inorganic compounds, excluding water, constitute 1% - 1.5% of cells Organic molecules, whose carbon atoms can combine in many ways with carbon atoms of other elements, are complex and can perform complex biological functions Small organic molecules can combine into large macromolecules