Atoms and Biology Matter and Life What makes stuff? ATOMS – Matter is essentially every thing on earth. If something exists, it has matter. Atoms and Life Atoms are the __________________ of a substance. You are already familiar with some common atoms: Gold, Silver, Copper. When you see these substances, you are essentially seeing millions of atoms “locked” together. Scientist currently recognize 92 naturally occurring elements (although there have been some man made elements). Matter and Life Of the 92 elements you will be responsible for memorizing….. 11 elements. The human body consists mainly of ____________________________. Of these elements it is fairly evident which ones we really need to look at: Atomic Structure Atoms have structures specific to each atom. However, every atom (except for Hydrogen) has a ____________________, and nucleus. The thing that differentiates atoms from one another is the number of these structures (specifically _________________________). Atomic Structure Within the atom is the _________________, a structure that is central to the nucleus. Within the nucleus are protons and neutrons. Each proton carries a _______________, while each neutron carries ______________ charge is neutral. The electrons carry a ____________________ and circle around the nucleus. In a neutral atom, the number of ____________________________ are equal. Atoms and Life How do scientists keep track of these atoms (also called __________________)? They use a tool called the periodic table. The periodic table provides information about each of the elements that exists. Atomic Structure Each element on the table contains specific information about that element. For each element there is the element’s symbol, atomic number, and atomic ma s s . The symbol is ___________________________________. The atomic number tells you the number of _______________ in the nucleus. The atomic mass is the ___________________________ in the nucleus. Atomic Structure The atomic mass is based upon the number of _______________________ This is because electrons are extremely light and contribute very little to the overall mass of an atom. Can an atom have differing numbers of neutrons and be the same element? YES! This is called an ________________. An isotope is also the reason that atomic masses have decimal places. Atomic Structure The electrons of an atom exist in ______________________________. The electron can exist in two states – ___________________________. W hen the electron moves from the ground to the excited state it ____________________ energy. W hen it returns to the ground state it __________________ the energy. This is how ________________________ is transmitted. Atomic Structure The electrons are the important part of the atom. It is the electrons that give the atom many of its chemical properties. The electrons, as we will learn later are what determine if the atom will bond to another atom. The formation of bonds between atoms involves the ________________________ of electrons. Chemical Compounds W ith only a limited number of elements on earth, how do we get the number of different things we have? These elements combine with one another to make what are know as ___________________________. Atoms join in unique ways based upon the configuration of their electrons. Chemical Compounds The majority of substances in nature do not exist as single elements, but rather as compounds. Formally, a compound results from the combination of ______________________________. Each element carries distinct properties. However, when the elements are combined, the new substance will have _____________________________. This is evident with such substances as __________________________. Chemical Bonds We talked about how elements can join to make new substances, but we need to know how these elements stay together. Compounds are held together by _________________________________. Chemical bonds are the “connections” that hold elements in a compound together. Chemical Bonds There are three main types of chemical bonding we are concerned with: Each of these involves the interaction of the _________________with another element. The ______________________________ is also dependent upon the _______________________ holding the elements together. Chemical Bonds _________________________ are formed when one or more electrons move from one atom to another. W hen these electrons leave one atom for another, a _________________in both atoms is created. W ith the opposite charges, there is an attraction between the atoms. This is _________________________of bond there is between atoms. Chemical Bonds Sometimes atoms don’t _______________ electrons, but rather __________________ electrons. This occurs due the atoms being ______________________________. W hen this bond forms, a special structure called a __________________ forms. You are familiar with many molecules: water, oxygen, carbon dioxide. Chemical Bonds The final type of bond occurs when molecules come into close proximity with one another. _____________________________________ result from the positive area of one molecule coming into contact with the negative area of another molecule. These forces are what keep the gecko on the wall as he is crawling. Water Molecules Even though a water molecule is essentially neutral in its charge, it does carry polarity. Polarity means that ___________________________________________. How can this possibly occur with a molecule that is said to be neutral? Water Molecules Water molecules contain 1 oxygen atom and 2 hydrogen atoms. The oxygen atom has a greater number of protons in its nucleus than the hydrogen (8 to 1). These protons have a greater attraction to the electrons of hydrogen. Therefore, the . This creates a ___________________ side to the water molecule and a ______________________ side. Water Molecules Because of this polarity, the water molecule will have ________________shape. However, the polarity is also responsible for the attraction of water molecule to one another. Bonding between water molecules is due to _____________________________. This type of is responsible for many of water’s properties. Water Molecules Water molecules may form _______________ bonds with other water molecules at any point in time. This allows for water to have two properties known as cohesion and adhesion. Cohesion is the . Adhesion is the . Solutions and Suspensions W ater is not always pure (just look at your tap water). Often times it is part of mixture of compounds. A mixture is a . Solutions and Suspensions Sometimes when a substance is placed in a liquid, the substance will break apart. This results in what is known as a ______________________. Solutions have two parts: The solute is the . The solvent is the substance that did Solutions and Suspensions Sometimes a substance will not dissolve in a liquid. However it will separate in to very small pieces and those pieces will not be able to settle. These small pieces will continue to float in the liquid. This combination of substances is known a _______________________________. Acids and Bases We have said that some substances dissolve in water. Sometimes when these substances dissolve, they form ions. Sometimes, the water will even react to form ions. Acids and Bases When water reacts to form ions, the reactions produces two specific ions. H+ and OH_ Usually, these ions in water are in equal number and cancel each other out and water is neutral. However, scientists have devised a method for determining the concentration of these ions in a liquid. Acids and Bases + The measurement system for indicating the concentration of H is the ____________________________ The scale ranges from 0-14. Solutions can be classified as either acidic (more H+) or basic (more OH_). Acids and Bases Each step on the pH scale represents a scale of 10. When you have an __________________________, you have a solution that forms more H+ in the solution. Acids have a pH below ___________ and strong acids have a pH between ________________. Essentially, what this means is that acids have a ______________________________________ Acids and Bases Obviously, when you have more OH_ you have a … Base Bases have a pH __________________ 7 with strong bases at a pH of ______________________. Many people have the misconception that only an acid will cause “burn” to the skin, but this is not true. Bases can cause just as much damage to the body. Acids and Bases As we said, the body likes to maintain a stable environment. Part of this internal environment involves controlling the pH. The body can control the pH through the use of substances called _________________________. Buffers are dissolved substances that are either weak _____________________. Basics of Carbon Carbon is one of the most important substances for living things. Carbon is so unique in its properties that it requires its own branch of chemistry. The unique properties of carbon are due to two reasons: Carbon has 4 ________________________________. Carbon bonds _______________________________. Basics of Carbon The body contains many different molecules. Sometimes, these molecules are so large that they are called ____________________________. Macromolecules are compounds that may be made of hundreds or even thousands of molecules. Macromolecules are made by a process called _______________________________. Macromolecules To form large macromolecules, substances called monomers (smaller units) join together to make polymers. Monomers in a polymer may be identical to one another or completely different. To be able to study these large macromolecules, scientists have divided these organic compounds into four groups. Carbohydrates The first main organic group are the carbohydrates. These substances are made of ___________________________________. Carbohydrates are the ______________________________ for living things. Carbohydrates When the body needs immediate energy, it will breakdown sugars like glucose. The simple sugars are also known by the name of ____________________________________. Stored supplies of extra sugar are in the form of complex carbohydrates known as starches. When monosaccarhides combine, they form _________________________. This is the type of molecule that many animals store as their energy supplies. Carbohydrates Plants use carbohydrates, but a slightly different version. This molecule is known as plant starch. Another polysaccharide plants make is cellulose. Lipids Another organic substance important to living things is lipids. Lipids are large molecules are large molecules that are typically ____________________________________________ Lipids are mostly composed of _____________________________ atoms. Lipids fall in to common categories called ______________________________. Lipids can be used to store energy, but as you will find when you get older it is hard to get to this energy source. Nucleic Acids Nucleic acids are macromolecules that contain __________________________________________________________ These macromolecules are made from the monomers called _________________. Nucleotides should be very familiar to you –What are they? Proteins The main building blocks for the body are contained in the macromolecules called _____________________ Proteins are made from ________________________________________. These substances are polymers of molecules called amino acids. Proteins There are four levels of organization for proteins. First, the sequence of the amino acids in the chain. Second, the sequence can be twisted or folded. Third, the chain can be folded. Fourth, if there is more than one chain, each chain has a specif ic arrangement. These levels of organization lead to the shape of the protein. As we begin to discuss the function of proteins, the shape of the protein will affect the function. Chemical Reactions and Enzymes Chemical Reactions Atoms make up all matter and atoms may combine How do these elements and compounds interact? Chemical reaction Chemical Reactions Compounds have different properties from the elements that made it Products of a chemical reaction have different properties than the substances that made it. Chemical reaction Involves: • Breaking of bonds in ___________________ and forming of new bonds in ________________________. Chemical Reactions Products and reactants. Reactants – . Products – . They may be substances, elements, or compounds. CO2 + H2O H2CO3 Note The number of atoms in the reactants equals the number of atoms in the products. Energy in Reactions Whenever a reaction occurs, energy is either absorbed or released. This energy is the result of bonds forming or bonds breaking. Energy considerations The most important factor in determining if a chemical reaction will occur. If chemical reactions release energy - _____________________________. Reaction absorbs energy - ______________________________________. Energy in Reactions Formation of water: Reaction between hydrogen gas and oxygen - energy releasing reaction. 2H2 + O2 2H2O + energy Energy released as heat in this reaction (but also may be light and sound). Reverse reaction can occur, but it requires so much energy input that rarely occurs without help. Only real way to reverse the reaction: Pass an electrical current through the water, a process called _______________________ Energy in Reactions Why do we need to know the energy requirements for reactions – why is that important for living things? For living things to remain ALIVE they have to take in energy to drive reactions that require energy. Energy in Reactions Some reactions that release energy will not occur spontaneously. Why might this be a good thing? Cellulose One of the major components of wood Burns in the presence of oxygen. Paper is made from…. WOOD! Your book could suddenly burst into flames if the reaction just occurred spontaneously. Energy in Reactions To light the fire you have to provide a flame. Flame contains energy, helps get the reaction started. Energy which helps the reaction start is called activation energy. Energy in Reactions Enzymes Some chemical reactions are far to slow to allow us to survive. Others require too much energy for activation energy. These reactions need a ______________________ a substance that speeds up the rate of a reaction. Catalysts work by lowering the activation energy for the reaction. Enzymes ________________________ act as catalysts in living organisms for chemical reactions. Many of the reactions in the body proceed too slow. Enzymes are very specific. They catalyze only one reaction. The name of the enzyme is specific to the reaction that it catalyzes. Enzymes Enzymes function by colliding with substances with enough energy so that bonds are broken and rearranged. Active site . When attachment occurs, the amount of energy needed for the reaction is reduced. Enzymes Enzyme process Reactants (the reaction that needs to occur) are called the ____________________________ Substrate has a site for the enzyme to attach. • Site is specific to the enzyme that is needed. Remember that enzymes are proteins and proteins undergo folding. Folding creates the shape of the enzyme so that it will fit in the attachment site of the substrate. Enzymes Enzymes are affected factors: pH Temperature Cells also can control the activity of enzymes by turning them on and off.
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