Presentation on theme: "Unit 2 Chemical Basis for Life. Chapter 6 Chemistry in Biology."— Presentation transcript:
Unit 2 Chemical Basis for Life
Chapter 6 Chemistry in Biology
Section 1: Atoms, Elements, & Compounds (p ) Section 2: Chemical Reactions (p ) Section 3: Water & Solutions (p ) Section 4: The Building Blocks of Life (p )
Section 1 Atoms, Elements, and Compounds
Objectives Living things consist of atoms of different elements Ions form when atoms gain or lose electrons Atoms share pairs of electrons in covalent bonds
The atom The atom is the smallest basic unit of matter Atoms are very small
The atom There are three parts of a an atom Subatomic particle ChargeLocation ProtonPositiveNucleus NeutronNeutralNucleus ElectronNegativeSurrounding nucleus
Elements An element is one particular type of atom, and it cannot be broken down into a simpler substance by ordinary chemical means Gold Aluminum Helium
Atoms & Elements Atoms & Elements
Key Elements In biology, there are SIX very important elements Carbon Hydrogen Oxygen Phosphorus Sulfur Nitrogen CHOPSN
How are elements different The number of protons determines the identity of an element Carbon: 6 protons Oxygen: 8 protons The number of electrons determines the property of an element Carbon: 6 electrons, 4 on OUTSIDE Oxygen: 8 electrons, 6 on OUTSIDE
Chemical Party https://www.youtube.com/watch?v=wBCmt_pJTRA
Lonely Atoms Atoms rarely are found alone in nature They will do ANYTHING to get to 8 electrons on the outside Steal Dump Share
Compounds A compound is a substance made of atoms of different elements bonded together Result of sharing, stealing, or dumping electrons Atoms bonded in a specific ratio
Carbon Compounds (more about this later) Carbon can form many various bonds to form Carbohydrates Proteins Nucleic acids Lipids
Ionic Bond Ionic bonds are formed through the electrical force between oppositely charged ions Opposites attract! Ex: Salt aka sodium chloride (NaCl) Positive sodium (Na + ) Negative chloride (Cl - )
NaCl – ionic bond
Ions Ions are atoms that have gained or lost one or more electrons. Results in a change in electrical charge Gain e - becomes negative Lose e - becomes positive
Ions, cont. Very important to organisms Hydrogen ions (H + ) needed to produce chemical energy in cells Calcium ions (Ca 2+ ) needed for all muscle movement in your body Chloride ions (Cl - ) needed for many chemical signals in the brain
Covalent Bond Not all atoms easily gain or lose their electrons! Some atoms share their electrons instead! Covalent Bond: forms when atoms share a pair of electrons Usually a very strong bond Atoms may have several covalent bonds to share several electrons
H 2 O – covalent bond
CO 2 – covalent bond
Covalent Bond, cont. Molecule: two or more atoms held together by covalent bonds Ex: carbon dioxide (CO 2 ) Carbon atoms needs 4 electrons to fill outer level, oxygen needs two Carbon shares with 2 oxygen!
Review What are atoms? How are the particles that make up atoms diagrammed? What are the similarities between covalent and ionic bonds?
Section 2 Chemical Reactions
Objectives Bonds break and form during chemical reactions. Chemical reactions release or absorb energy.
Evidence of a chemical reaction Temperature change Formation of a solid (precipitate) Color change (sometimes) Odor (sometimes) Formation of gas
Chemical Reaction... Gummy bear torture
Bonds break & form during chemical reactions Plant/Animal cells break down sugars to get usable energy Cells build protein molecules by bonding amino acids together Chemical reactions change substances into different substances by breaking and forming chemical bonds
Reactants are the substance changed during a chemical reactions Oxygen (O 2 ) & Glucose (C 6 H 12 O 6 ) Products are the substances made by a chemical reaction Carbon Dioxide (CO 2 ) & Water (H 2 O) 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O
Reactants & Products
Energy is needed to break bonds in molecules Bond energy is the amount of energy that will break a bond between two atoms. Every atom has different bond energy A SPECIFIC amount of energy is needed to break bonds in an oxygen molecule A SPECIFIC amount of energy is needed to break bonds in a glucose molecule Energy is released when bonds are formed The amount of energy released is equal to the energy that breaks the same bond Energy needed to break apart water molecule = energy released when hydrogen & oxygen atoms bond to form a water molecule
All chemical reactions involve changes in energy Energy added to the reactants breaks their chemical bonds When new bonds form in the products, energy is released Energy is both absorbed and released during a chemical reaction! Some release more energy than they absorb (Generous) Some absorb more energy than they release (Greedy)
Generous chemical RXNs that release more energy than they absorb = Exothermic reaction Excess energy is the difference in bond energy between the reactants and products Excess energy is often released as heat or light Cellular respiration releases usable energy for your cells & heat!
Greedy chemical RXNs that absorb more energy than they release = Endothermic reaction In photosynthesis, plants absorb energy from sunlight and use that to make sugars and carbohydrates
Exothermic VS. Endothermic graphs
But how does a rxn start? Some energy must first be absorbed by the reactants in ANY chemical reaction The amount of energy needed will vary Activation energy is the amount of energy that needs to be absorbed for a chemical reaction to start Push a rock up a hill
Activation energy Activation Energy Activation Energy
Catalysts & Enzymes A catalyst is a substance that lowers the activation energy needed to start a chemical reaction. Special proteins called enzymes are the biological catalysts that speed up the rate of chemical reactions in biological processes.
Review What are the parts of a chemical reaction? How can energy changes be related to chemical reactions? What is the importance of enzymes in living organisms?
Section 3 Water and Solutions
Objectives Life depends on hydrogen bonds in water. Many compounds dissolve in water. Some compounds form acids or bases.
Organisms’ bodies, (their _____________), are made up of mostly ____________________ The water in cells gives the cell _______________ and ___________________ materials within organisms. All of the processes necessary for an organism’s life take place within the ______________________________ of the cell CELLS WATER STRUCTURE TRANSPORTS WATERY ENVIRONMENT
Negative Charge Positive Charge Water is a “______________” molecule Form when atoms in a molecule have ____________ pulls on the _____________ they share. Opposite charges of polar molecules can interact to form ____________________ bonds. An attraction between a slightly _______________ hydrogen atom and a slightly ______________ atom. (Usually _______________________________) Hydrogen bonds are part of the structures of _______________ and of ______________ Shared Electrons POLAR UNEQUAL ELECTRONS HYDROGEN POSITIVE NEGATIVE OXYGEN OR NITROGEN PROTEINS DNA
Cohesion : the attraction among __________________ of the same substance. Cohesion from hydrogen bonds makes water molecules _____________________. Cohesion produces __________________, ( “skin on water” ) MOLECULES STICK TOGETHER SURFACE TENSION
Adhesion : the attraction among __________________ of ______________ substances. For example, water molecules stick to other things. Water in a test tube, (water is attracted to the ____________) MOLECULES DIFFERENT GLASS
Materials such as ________________ and ____________ cannot be transported form one part of an organism to another unless they are dissolved in blood, plant sap, or other water based fluids. ______________: Mixture of a substance that is the same throughout. ___________: Substance that is present in the greater amount and dissolves another substance. ___________: Substance that dissolves in a solvent. SUGARS OXYGEN SOLUTION SOLVENT SOLUTE
Mixtures Heterogeneous A mixture with easily separated parts with their distinct properties Homogeneous A mixture that it the SAME throughout and hard to tell individual characteristics
Some compounds form ______________ or _____________ because they _______________ into _______________ when they dissolve in ___________. BASE : Compounds that remove H+ ions from a solution ACID: Compounds that release a proton - a hydrogen ion(H+) – when it dissolves in water ACIDS BASES BREAK UP IONS WATER
More acidic More basic neutral
pH Scale examples
Review How does the structure of water make it a good solvent? What are the similarities and differences between solutions and suspensions? What are the differences between acids and bases?
Section 4 The Building Blocks of Life
Objectives Carbon atoms have unique bonding properties. Four main types of carbon-based molecules are found in living things.
____________________ PROTEIN LIPIDS CARBOHYDRATES ATP NUCLEIC ACID
Carbohydrates are molecules composed of carbon, hydrogen, and oxygen Include sugars & starches Can be broken down to provide useable energy for cells Major part of plant cell structure The most basic carbs are simple sugars, monosaccharides Polysaccharides are polymers of monosaccharides
USED BY CELLS FOR __________ ___________ AND __________ ____________. SIMPLE CARBS = _______________________________ COMPLEX CARBS = _____________________________ _____________________________ ENERGY SOURCE ENERGY STORAGE ONE OR TWO SUGAR MOLECULES LONG CHAINS OF SUGAR MOLECULES Ex) Starches such as potato, pasta, bread ________________________________
Proteins are the most varied of the carbon-based molecules in organisms Have a role in movement, eyesight, digestion, etc. A protein is a polymer made of monomers called amino acids Amino acids are molecules that contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur Organisms use 20 different amino acids to build proteins The body makes 12 of the 20, the other 8 come from food
MAKE UP _________________. INVOLVED IN ALL _______ ____________. BUILDING BLOCKS = _________ __________. _________________= TYPE OF PROTEIN THAT STARTS AND SPEEDS UP CHEMICAL REACTIONS IN CELLS. CELLS LIFE PROCESSES AMINO ACIDS ENZYME
Lipids are nonpolar molecules that include fats, oils, and cholesterol Contain chains of carbon bonded to oxygen & hydrogen Some broken down for useable energy Others are part of a cell’s structure Fatty acids are chains of carbon atoms bonded to hydrogen atoms. Saturated fatty acids have single carbon-carbon bonds Unsaturated fatty acids have double carbon- carbon bonds
DON’T MIX WITH ______________. PHOSPHOLIPIDS – MAKE UP ________ ______________. FATS AND OILS THAT _________ ___________. ORGANISMS USE FATS AND OILS WHEN THEY HAVE USED UP ___________________. _________- SOLID AT ROOM TEMPERATURE. _________- LIQUID AT ROOM TEMPERATURE. WATER CELL MEMBRANE STORE ENERGY CARBOHYDRATES FATS OILS
MAJOR ___________ ___________ MOLECULE IN CELL. ENERGY IN __________________ AND __________ AND _____________________ MUST BE TRANSFERRED TO ATP IN CELL TO BE USED. ENERGY CARRYING CARBOHYDRATES LIPIDS PROTEINS
Detailed instructions to build proteins are stored in extremely long carbon-based molecules called nucleic acids Nucleic acids are polymers that are made up of monomers called nucleotides Nucleic acids differ from the other carbon- based molecules The others have a large # of functions Nucleic acids have just 1 function… make proteins DNA stores info for putting amino acids together to make proteins RNA helps to build proteins
HAVE ALL INFO NEEDED TO MAKE __________. “_______________” OF LIFE. BUILDING BLOCKS OF _____________. TWO TYPES: ________ AND _______. PROTEIN BLUE PRINT NUCLEOTIDES DNA RNA
Each subunit of a complete carbon- based molecule is called a monomer A polymer is a large molecule, or macromolecule, made of many monomers bonded together Monomers of a polymer may be the same (ex. Starches) Or different (proteins)