Biology 1201 Unit 1 Chapters 1 5 Check Moodle for videos homework Green Definitions Blue Lists Orange Questions Asked in Class I Introduction a What is Science A study of the natural world to acquire a body of knowledge A way of understanding the natural world It is a process input to a body of knowledge output b What do scientists do Make observations Make models Make predictions hypotheses Discern Patterns Assume that the future is like the past c Scientific Method What are the basic steps of the method o Observations Generalization or Model Predictions or Hypothesis Test What is the outcome of this process o Make new observations o Find more information o Create better models Terminology Hypothesis Theory A prediction or explanation for a phenomenon that is untested it is a statement an explanation or prediction for something that has been tested many times and is a theory that has been continuously tested widely believed by scientists closest to supported believed to be accurate Law reality most tested What is Biology The scientific study of life What is life It is made up of many characteristics What are the characteristics of life Underlined words will be covered in class Organization Use energy Adapt Respond to environment Growth and development Reproduce Evolve Made up of cells It is important to realize that each characteristic by itself cannot support life Living things must have ALL of these characteristics to be considered living things Example Viruses do not have all these characteristics so they aren t alive Antibiotics kill bacterial infections and cannot kill viruses What determines solubility Like dissolves like Compounds which are similar dissolve one another Polar solutes dissolve in polar solvents Nonpolar solutes dissolve in nonpolar solvents Like in terms of polarity What determines polarity The type of bonds within a molecule The sharing of electrons determines polarity Example nonpolar molecules can enter through the cell membrane but polar molecules cannot II Basic Chemistry Scale of Nature What are the sizes of biologically important structures Solubility like dissolves like Atoms Atomic Structure Smallest units of matter that are separable by normal chemical means Smallest unit of an element that retains all the elements properties Composed of many smaller particles Particle Proton Neutron Electron Mass 1 Dalton 1 Dalton 0 Daltons Electric Charge Location Nucleus Nucleus Outside of Cell Electrons DO have mass but it is very small Electrons make up the volume of an atom and protons neutrons make up the mass Valence Bonding capacity The number of electrons that need to be gained or lost to fill the outer shell of electrons Also predicts the number of bonds that an atom will form They will want to gain or lose the SMALLER number Valence electrons chemistry The electrons in the outermost shell Questions Lithium has the atomic number of 3 What is the valence of Li Carbon has the atomic number 6 What is the valence Bohr Model 1 4 The Next level L The Third Level M This model has electrons moving in orbitals or shells around the nucleus The electrons always try to be in the lowest orbital or energy shell that is closest to the nucleus The Lowest Level K o An atom is most stable when the outer most shell of electrons was full Oxygen has the atomic number 8 What is its valence bonding capacity Questions 2 2K 6L Easier for it to gain 2 than lose 6 2 K 8 L 5 M Easier for it to gain 3 than lose 5 Phosphorus has the atomic number 15 What is the valence bonding capacity Atoms will try to gain or lose electrons in order to fill their outer shell or valence shell The number of electrons to be gained or lost is called the valence Chemical Bonds Form when atoms gain and lose or share electrons They are the result of electrical attractions between atoms Ionic Bonds Form when atoms completely gain and lose electrons Strongest bonds when dry Covalent Bonds Form when atoms share electrons If shared equally then they are nonpolar covalent If shared unequally polar covalent Strongest bonds in water Clicker Questions Are Covalent Polar Covalent and Ionic Bonds really different bonds They are similar except for the degree of sharing of electrons What determines the number and type of chemical bonds Number determined by the valence Type determined by Electronegativity The measure of the tendency of an atom to attract a bonding pair of electrons Electronegativity Measure of the attraction an atom has for electrons If it wants to gain an electron HIGH If it wants to lose an electron LOW As you go from left to right across the periods of the periodic table the electronegativity increases The electronegativity of the Nobles Gases is ZERO The electronegativity also increases as you go up a group when differences are 1 7 or greater the bond is usually ionic Electronegativity and Bonds Ionic Covalent non polar when differences of less than 0 5 Polar Covalent when the difference is greater than 0 5 and less than 1 7 it is a polar covalent bond Clicker Questions The Carbon Carbon bond is which type of bond electronegativity Covalent because the electronegativity is 2 5 2 5 2 5 0 0 is less than 0 5 which corresponds to Polar Covalent because the electronegativity is 3 5 2 5 1 0 between 0 5 1 7 which a Nonpolar Covalent Bond The Carbon Oxygen bond is which type of bond corresponds to a polar covalent bond The Na Cl bond is which type of bond bond The C H bond is which type of bond How do bonds influence the polarity of a molecule Ionic because the electronegativity is 3 0 0 9 2 1 greater than 1 7 which corresponds to an ionic Covalent because 2 5 2 1 0 4 less than 0 5 which corresponds to a nonpolar covalent bond Molecules which contain a majority of ionic bonds will be polar Molecules which contain a majority of polar covalent bonds will be polar with some exceptions Molecules which contain a majority of pure covalent bonds will be non polar Strong Bonds Bonds which are the result of very strong electrical attractions where electrons are lost or Bonds which are the result of electrical attractions which are not so strong where the electrons gained are called Ionic Bonds are shared are covalent bonds Weak Bonds Bonds which are not involved in making a substance Hydrogen Bonds o Weak electrical attractions between atoms on different molecules or different parts of a large molecule a type of weak bond o Occur between molecules than have polar covalent to ionic bonds o In a water molecule
View Full Document
Unlocking...