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Biology - Chp 2 - The Chemistry Of Life - PowerPoint
 

Biology - Chp 2 - The Chemistry Of Life - PowerPoint

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  • Sodium – silver colored metal, soft enough to cut with a knife
  • Sodium reacting explosively in water
  • Chlorine – poisonous green gas used to kill many people in WWII
  • Combination of sodium and chlorine

Biology - Chp 2 - The Chemistry Of Life - PowerPoint Biology - Chp 2 - The Chemistry Of Life - PowerPoint Presentation Transcript

  • Chapter 2 The Chemistry of Life
  • Section 1: The Nature of Matter
  • Objectives
    • What three subatomic particles make up atoms?
    • How are all the isotopes of an element similar?
    • What are the two types of chemical bonds?
  • The Big Idea
    • Life Depends on chemistry
    • Chemical reactions keep you alive
  • Atom
    • Basic unit of matter
  • Democrites
  • Subatomic particles
    • Protons -
    • Neutrons -
    • Electrons -
    • Positively charged (+)
    • Not charged (neutral)
    • Negatively charged (-)
    Bind together to form the nucleus Electrons Protons Neutrons Nucleus
  •  
  • Element
    • A pure substance that consists of just one type of atom
  •  
  • 6 C Carbon 12.011 Atomic number An elements atomic number = number of protons
  • Isotope
    • Atoms of the same element that differ in the number of neutrons they contain
  • Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons 6 electrons 6 protons 7 neutrons
  • 6 C Carbon 12.011 Mass number The Sum of protons and neutrons in the nucleus of an atom is its mass number
    • The weighted average of the masses of an elements isotope is called its atomic mass
  • Radioactive isotopes
    • Can be dangerous
    • Can be used practically
      • Radioactive dating
      • Treat cancer
      • Kill bacteria
  • Compounds
    • A substance formed by the chemical combination of two or more elements in definite proportions
    • Ex) H 2 O, NaCl
  •  
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  • Table Salt
  • Ionic Bonds
    • Formed when one or more electrons are transferred from one atom to another
  • Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na + ) Chloride ion (Cl - ) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1
    • If an atom loses an electron it becomes positive
    • If an atom gains an electron it becomes negative
  • Ions
    • Positively and negatively charged atoms
  •  
  • Covalent Bonds
    • Forms when electrons are shared between atoms
  •  
  • Molecule
    • The structure that results when atoms are joined together by a covalent bond
    • Smallest unit of most compounds
  • Van der Waals Forces
    • A slight attraction that develops between the oppositely charged regions of nearby molecules due to unequal sharing of electrons
  •  
  •  
  • Homework
    • Describe the structure of an atom.
    • Atoms are made up of protons and neutrons in a nucleus. Electrons are in constant motion in the space around the nucleus.
    • Why do all isotopes of an element have the same chemical properties
    • They have the same number of electrons
    • 3. What is a covalent bond?
    • A bond formed when electrons are shared between atoms
    • 4. What is a compound? How are they related to molecules
    • A compound is a substance formed by the chemical combination of two or more elements in definite proportions. A molecule is the smallest unit of most compounds
    • 5. How do Van der Waals forces hold molecules together?
    • When the sharing of electrons are unequal, a molecule has regions that are charged. An attraction can occur between oppositely charged regions of nearby molecules
    • 6. How are ionic bonds and Van der Waals forces similar? How are they different?
    • In both cases, particles are held together by attractions between opposite charges. The difference is that ionic charges are stronger
  • Section 2: Properties of Water
  • Objectives
    • Why are water molecules polar?
    • What are acidic solutions? What are basic solutions?
  • The Big Idea
    • Much of our planet is covered in water
    • Water is necessary for life to exist
    • If life exists on other planets, there most likely is water present
    • Water has many properties that make life possible
  • Polarity (-) (+) The oxygen atom has a stronger attraction for electrons
  • Hydrogen Bonds
    • Because of waters partial charges, they can attract each other and create hydrogen bonds
    • Not as strong as covalent or ionic bonds
    • Waters ability to create multiple hydrogen bonds gives it many special properties
  • Cohesion
    • Attraction between molecules of the same substance
  •  
  •  
  • Adhesion
    • Attraction molecules of different substances
  •  
  • Mixture
    • Material composed of two or more elements or compounds that are physically mixed but not chemically combined
    • Ex.) salt & pepper, earths atmosphere
  • Solutions
    • Mixture of two or more substances in which the molecules are evenly distributed
    • Ex.) salt water
    • Settles out over time
  • Solutions Cl - Water Cl - Na + Water Na +
  • Solute
    • Substance that is dissolved
    • Ex.) salt
  • Solvent
    • The substance that does the dissolving
    • Ex.) Water
  • Suspensions
    • Mixture of water and non-dissolved materials
    • Ex.) sugar solution, blood
    • Separate into pieces so small, they never settle out
  • The pH scale
    • Indicated the concentration of hydrogen ions in a solution
  • Neutral Acid Base
  • Acids
    • Any compound that forms H + (hydrogen) ions in solution
  • Base
    • A compound that produces OH - (hydroxide) ions in solution
  • Buffers
    • Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden pH changes
  • Homework
    • Use the structure of a water molecule to explain why its polar
    • Oxygen atom has greater attraction for electrons, therefore the oxygen atom is negative and the hydrogen end is positive
    • 2. Compare acidic and basic solutions in terms of their H + ion and OH - ion concentrations
    • Acid have more H + ions than OH - ions, and bases have more OH - ions than H + ions
    • 3. What is the difference between a solution and a suspension?
    • In a solution, all components are evenly distributed. In a suspension, un-dissolved particles are suspended
    • 4. What does pH measure?
    • The concentration of H + ions in a solution
    • 5. The strong acid hydrogen floride (HF) can be dissolved in pure water. Will the pH of the solution be greater or less than 7?
    • less than 7
  • Section 3: Carbon Compounds
  • Objective
    • What are the functions of each group of organic compounds?
    • Most of the compounds that make up living things contain carbon. In fact, carbon makes up the basic structure, or “backbone,” of these compounds. Each atom of carbon has four electrons in its outer energy level, which makes it possible for each carbon atom to form four bonds with other atoms.
    • As a result, carbon atoms can form long chains. A huge number of different carbon compounds exist. Each compound has a different structure. For example, carbon chains can be straight or branching. Also, other kinds of atoms can be attached to the carbon chain.
    Life’s backbone Section 2-3 Interest Grabber
  • Methane Acetylene Butadiene Benzene Isooctane
  • Macromolecules “giant molecules”
    • Formed by a process called polymerization
  • Monomers
    • Smaller units
  • Polymers
    • Linked up monomers
  • Carbohydrates
    • Compounds made up of carbon, hydrogen, and oxygen atoms usually in a ratio of 1:2:1
    • Main source of energy
    • The monomers of starch are sugars
    • Single sugar molecules are called monosaccharides
    • The large macromolecules formed from monosaccharides are known as polysaccharides
  • Starch Glucose
  • Lipids
    • Made mostly from carbon and hydrogen atoms
    • Used to store energy
  • Lipid Glycerol Fatty Acids
  • Proteins
    • Macromolecules that contain nitrogen as well as carbon, hydrogen, and oxygen
    • Proteins are polymers of molecules called amino acids
  • Amino Acids General structure Alanine Serine Carboxyl group
    • More than 20 different amino acids, can join to any other amino acid
    • The instructions for arranging amino acids into many different proteins are stored in DNA
    • Each protein has a specific role
    • The shape of proteins can be very important
  • Proteins Amino Acids
  • Nucleic Acids
    • Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus
    Double Helix
  • Nucleotides
    • Consists of 3 parts: 5-carbon sugar, phosphate group and nitrogen base
    Nitrogen Base 5-Carbon Sugar Phosphate group
  • 2 kinds of nucleic acids
    • RNA (ribonucleic acids) – contains sugar ribose
    • DNA (deoxyribonucleic acid) – contains sugar deoxyribose
  • Homework
    • Name four groups of organic compounds found in living things
    • carbohydrate, lipid, protein, nucleic acids
    • 2. Describe at least one function of each group of organic compounds
    • carbohydrates – energy
    • lipids – store energy
    • proteins – form tissue
    • nucleic acids – transmit hereditary information
    • 3. Compare the structures and functions of lipids and starches
    • Lipids are made from carbon and hydrogen. Starches are made of carbon, hydrogen and oxygen. They both can be used to store energy
  • Section 4: Chemical Reactions and Enzymes
  • Objectives
    • What happens to chemical bonds during chemical reactions?
    • How do energy changes affect whether a chemical reaction will occur?
    • Why are enzymes important to living things?
  • The Big Idea
    • Living things are made up of chemical compounds
    • Everything that happens to an organism is based on chemical reactions
  • Chemical Reactions
    • A process that changes or transforms one set of chemicals into another
  • Reactants
    • Elements or compounds that enter into a reaction
  • Products
    • Elements or compounds produced by a chemical reaction
  • Example Reaction: Getting rid of carbon dioxide
    • In the blood
    • In the lungs
    CO 2 + H 2 0  H 2 CO 3 (carbonic acid) H 2 CO 3  CO 2 + H 2 O Released as you breathe
  • Energy in reactions Energy-Absorbing Reaction Energy-Releasing Reaction Products Products Activation energy Activation energy Reactants Reactants
  • Activation Energy
    • The energy that is needed to get a reaction started
  •  
  • Enzymes
    • Some chemical reactions are too slow or have activation energies that are too high to make them practical for living tissue
    • These chemical reactions are made possible by catalysts
  • Catalyst
    • Substance that speeds up the rate of chemical reactions
    • Work by lowering a reactions activation energy
  • Enzyme
    • Biological catalysts
    • Speed up reactions in cells
    • Very specific
    • Named for the reaction is catylzes
    • Enzyme names always end in -ase
  • Reaction pathway without enzyme Activation energy without enzyme Activation energy with enzyme Reaction pathway with enzyme Reactants Products
  • Substrates
    • The reactants of enzyme catalyzed reactions
    • The active site of the enzyme and the substrate have complementary shapes
    • Fit like a lock and key
  • Enzyme Action Enzyme – substrate complex
  • Glucose Substrates ATP Substrates bind to enzyme Substrates are converted into products Enzyme-substrate complex Enzyme (hexokinase) ADP Products Glucose-6- phosphate Products are released Active site
  • Regulation of Enzyme Activity
    • Enzymes are affected by any variable that affects chemical reactions
    • pH
    • Temperature
    • Concentration
    • of enzyme
  •  
  • Homework
    • What happens to chemical bonds during chemical reactions
    • Bonds are broken in reactants and new bonds are formed in products
    • 2. Describe the role of energy in chemical reactions
    • some chemical reactions release energy, and other chemical reactions absorb energy. Energy changes determine how easily a chemical reaction will occur
    • 3. What are enzymes, and how are they important to living things?
    • Enzymes are biological catylasts. Cells use enzymes to speed up virtually every important chemical reaction that takes place in cells
    • 4. Describe how enzymes work, including the role of the enzyme substrate complex
    • Substrates, the reactants of an enzyme-catylzed reaction, attach to the enzyme at an active site and form an enzyme – substrate complex. Once the complex is formed, the enzyme helps convert substrate into product
    • 5. A change in pH can change the protein. How might a change in pH affect the function of an enzyme such as hexokinase (hint: think about the analogy of the lock and key)
    • A change in pH could change the shape of hexokinase. This change would diminish the ability of glucose and ATP to bind to the active site of the enzyme.