BIOSCI 0815 1st Edition Lecture 2 Outline of Last Lecture I. Tay-Sachsa. CarriersII. TwinsIII. Chemical Reactionsa. EnzymesIV. DNAV. Genetic DisordersOutline of Current Lecture II. What is MatterIII. Atomsa. ElectronsIV. Types of bondinga. Importance of WaterV. Cells and Cellular structureVI. Connection to Tay-SachsCurrent Lecture- Mattero Matter is anything that has and takes up space. Mass is the amount of matter that an object has. Note: Mass and eight are not the same. Weigh is related to gravity while mass is constant. o Matter is made up of elements which are units that cannot be broken apart to a different substance through chemical reactions.- Atoms:o Atoms are the smallest units that chemists work with. Some examples are oxygen, hydrogen, aluminum and iron. There are even smaller parts of atoms.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Terms: Neutrons are located in the nucleus of the atom and they contain no charge. Protons are also in the nucleus and have a positive charge.  Electrons orbit the nucleus and have a negative charge.  Atomic mass is the number of protons and neutrons in the nucleus of a atom. The atomic number is the number of protons (number of neutrons can change while the number of protons in an atom is always constant for that type of atom.For example. Hydrogen always has one proton, which is why its atomic number is 1).o The periodic table organizes atoms. A group of atoms (a column on the periodic table) has the same number of electrons in the outermost shell. In a row of atoms, each atom to the right has one more electron than the previous element.o Electron energy levels: The closer the electron shell is to the nucleus, the lower potential energy it has. As it gets farther it has more potential energy. The shells of an atom always wantto be full. The first shell can contain a maximum of two electrons. The next shellscan have eight.  Atoms will form bonds to have energetically favored, stable outer shells. o Molecule: a molecule is a substance composed of two or more elements. o Compound: a compound is different elements in a bond (different from molecule because they have to be different elements where a molecule can have the same elements in a bond)- Type of Bonds:o Elements for bonds because they are energetically more stable when all electrons a shellcan have are filled. (first shell can hold two, second and third shells can hold eight).o Ionic bonds: in an ionic bond, an atom completely gives or takes an electron to or from another atom. This results in positively and negatively charged atoms which are attracted to each other. An anion is an atom that becomes negative when it gains an electron. (think A_N(egative)_ION  A cation becomes positive when it loses an electron (if it helps think of the t in cation as a plus sign ca+ion) NaCl (table salt) is an important example of a polar bond.o Covalent bonding is when atoms share electrons. Non polar covalent bonds occur when there is equal sharing of the electrons. Polar bonds occur when one element is more electronegative than another. This results in a slight charge on either end of the molecule (hence, “polar” covalent bond). Non polar covalent bonds occur in molecules such as H2, O2, and CH4 when all electrons spend equal time around the two elements in the bond.  One of the most important polar molecule is water. In H2O there is an unequal sharing of electrons. Oxygen has a higher attraction for electrons, so they tend to stay by the oxygen.- - When there are lots of water molecules together the polar ends are attracted to each other. This is called hydrogen bonding, which is a weakintermolecular force but in large amounts can be very strong. Because ofthese polar ends of water, it is both highly cohesive (it sticks together in droplets) and adhesive (it is attracted to the surface on which it rests, imagine the inside of a glass).o The slight charges in water are attracted to charges in salt which is why it dissolves in water. o When something is hydrophilic, it means that it is “water loving”and wants to be with and around water. If it is hydrophobic, it fears water.o Cells: Atoms are the base of life. When they join, they make increasingly complex structures:- Atoms  molecules  organelles  cells  tissues  organs  organ systems  organisms Cells are composed of a hydrophobic substance. The cell keeps out certain chemicals and allows others to pass through the cell membrane. This also prevents the cell from dissolving. o Tay-Sachs: Something is wrong with the chemistry in the children: the wrong chemicals were made which means that they cannot exchange electrons or form bonds as others