BIOSCI 0815 1st Edition Exam# 1 Study Guide Lectures: 1 - 7Lecture 1 Terms to Know: Enzymes, MutationsWhat is Tay Sachs?Tay-Sachs is a disease caused by the inability to process a protein that breaks down fat in the brain, resulting in a fat build up in the brain. It is usually fatal to children, but some variations of the disease affect adults. Some cultures and groups of people are more vulnerable to this disease such as Ashkenazi Jews, French Canadians, Lousisan Cajuns. One in 250 of the general population will have this disease. Tay-Sachs is passed genetically by parents who are both carriers of the disease.What are carriers?Carriers are people who do not have the symptoms of the disease but can pass it on to their children. This is when the disease is only shown in the recessive gene (little “a”). The child must have two recessive genes to show signs of the disease. Parents with the genes Aa are carriers of the disease. If two carriers have a child, that child has a 1 in 4 chance of having the disease (aa). The child has a 1 in 2 chance of being a carrier and a 1 in 4 chance of being free of the disease.In the graph below, one parent is a carrier and one is not. None of the children have a chance of having the disease but some may be carriers.The problem that causes Tay-Sachs is that the child is missing an enzyme (a chemical that helps other chemical reactions to occur. In the absence of this enzyme, reactions may not occur or may take a long time to occur.What are Enzymes?Enzymes bring chemicals together so that reactions can occur. They are not used up in the reaction.Enzymes are a type of protein. Proteins are a versatile class of chemicals which carry out functions in the cells. They can be receptors which receive signals that tell cells what to do or they can help reactions occur.DNA is the genetic code. What are the steps from DNA to Enymes?A copy of DNA is made. This is called RNA. The process of making the copy is transcription. RNA is able toleave the nucleus of a cell. Then it is translated so that proteins ca be made. Once it is no longer needed the RNA copy degenerates. What are Genetic Disorders? What are mutations?Genetic disorders are when something is wrong with the instructions in the DNA of how to make a protein. Often a mutation alters the information in the genetic code. IN genetic diseases the genetic codeis mutated which means that the information for a protein is changed from normal. Often the causes of the mutations that result in genetic disorders are unknown. Exposure to UV radiation, toxic chemicals, alcohol, drugs, and tobacco are related to a higher incidence of mutation.To prevent this, couples can undergo genetic counseling. In addition, scientists are trying to understand the genome to see if cures can be made by changing it. Sometimes replacement drugs can supplement a protein that cannot be made due to genetic mutations. Lecture 2 Terms To Know: Matter, Element, Mass, Atom, Atomic number, Atomic mass, Proton, Electron, Neutron, Energy shell, Atom nucleus, Periodic Table, Valence shell = outermost shell in an atom, Molecule, Compound, Chemical bond, Electronegativity, Covalent bond, Polar, Non-polar, Ionic bond, Anion, Cation,Hydrogen bond, Hydrophilic, HydrophobicWhat is Matter?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. Matter is made up of elements which are units that cannot be broken apart to a different substance through chemical reactions.What is an atom, neutron, proton, electron, Atomic Mass and Atomic Number, energy level?Atoms are the smallest units that chemists work with. Some examples are oxygen, hydrogen, aluminum and iron. There are even smaller parts of atoms.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 an 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).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. The closer an 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 want to be full. The first shell can contain a maximum of two electrons. The next shells can have eight. Atoms will form bonds to have energetically favored, stable outer shells. A molecule is a substance composed of two or more elements. 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)What are bonds and what are the types of bonds?Elements form bonds because they are energetically more stable when all electrons a shell can have are filled. (The first shell can hold two, second and third shells can hold eight).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.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. Thisresults 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 timearound the two elements in the bondWhat is the Importance of 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