Biochemistry review presentation

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Biochemistry review presentation

  1. 1. Chemistry in Biology Chemistry in Biology
  2. 2. Atoms, Elements, Compounds <ul><li>Atoms are the building blocks of matter. </li></ul>The nucleus is at the center of the atom. Positively charged particles called protons and particles with no charge called neutrons are located in the nucleus. Electrons with negative charges are located outside the nucleus. Atoms contain an equal amount of protons and electrons and have a total charge of zero.
  3. 3. Elements <ul><li>An element is a substance that cannot be broken </li></ul><ul><li>down by physical or chemical means. </li></ul><ul><li>Elements are organized in a periodic table based </li></ul><ul><li>on the arrangement of their electrons. </li></ul><ul><li>The four most common elements in living things </li></ul><ul><li>are Carbon, Hydrogen, Oxygen and Nitrogen. </li></ul>
  4. 4. Isotopes, Radioactive Isotopes Atoms of the same element that have different numbers of neutrons are called isotopes. If an atom is unstable , the nucleus can decay and give off radiation – these are called radioactive isotopes. Carbon-14 is a radioactive isotope that is found in all living things. Scientists can determine how old an object is by determining how much Carbon 14 is in the object.
  5. 5. Compounds <ul><li>A compound is a pure substance formed </li></ul><ul><li>when two or more different elements </li></ul><ul><li>combine. Compounds can not be broken </li></ul><ul><li>down by physical means. </li></ul>Water is the compound H 2 O. Table salt is the compound NaCl. Hydrocarbons are compounds made of Carbon and Hydrogen. Methane CH 4 is a hydrocarbon.
  6. 6. Chemical Bonds <ul><li>Chemical bonds hold substances together </li></ul><ul><li>by either sharing or donating electrons </li></ul><ul><li>between atoms. </li></ul><ul><li>Covalent bonds form when electrons are </li></ul><ul><li>shared between atoms. </li></ul><ul><li>A molecule is a compound held together by </li></ul><ul><li>covalent bonds. </li></ul>
  7. 7. Covalent Bonds <ul><li>Sometimes atoms will form more than one </li></ul><ul><li>covalent bond between their electrons, </li></ul><ul><li>double or triple bonds. </li></ul>
  8. 8. Ions <ul><li>Ions form when atoms gain or lose electrons. </li></ul><ul><li>Some ions are positively charged Na + and some </li></ul><ul><li>ions are negatively charged Cl - </li></ul>
  9. 9. Ionic Bonds <ul><li>An ionic bond forms through the electrical </li></ul><ul><li>force between oppositely charged ions. </li></ul><ul><li>Substances that form from ionic bonds are </li></ul><ul><li>called ionic compounds. </li></ul>
  10. 10. Chemical Reactions <ul><li>A chemical reaction is the process by which atoms or </li></ul><ul><li>groups of atoms in substances are reorganized into </li></ul><ul><li>different substances. </li></ul><ul><li>A chemical equation shows the reactants and the </li></ul><ul><li>products. </li></ul><ul><li>In a balanced equations , mass is </li></ul><ul><li>conserved and coefficients show </li></ul><ul><li>that the number of atoms of each </li></ul><ul><li>element is the same before and </li></ul><ul><li>after the reaction. </li></ul>
  11. 11. Energy of Reactions <ul><li>Activation energy is the minimum amount </li></ul><ul><li>of energy need for reactants to form </li></ul><ul><li>products in a chemical reaction. </li></ul>Exothermic Reaction Endothermic Reaction
  12. 12. Enzymes <ul><li>A catalyst is a substance that lowers the </li></ul><ul><li>activation energy to start a reaction. </li></ul><ul><li>Enzymes are biological catalysts that </li></ul><ul><li>speed up the rate of chemical reactions in </li></ul><ul><li>biological processes. </li></ul>Most enzymes are proteins. Temperature and pH changes can alter the shape of an enzyme and lower its activity.
  13. 13. Enzyme/Substrate/Product <ul><li>S ubstrate s are the substances acted </li></ul><ul><li>on by enzymes. They bind at the active </li></ul><ul><li>site. </li></ul>The “lock and key” model
  14. 14. Water is a Polar Molecule <ul><li>In water, electrons spend more time near </li></ul><ul><li>the oxygen nucleus than the hydrogen </li></ul><ul><li>nuclei. </li></ul>Molecules that have an unequal distribution of charges are called polar molecules . In water, the electrical attraction between the negative oxygen side of one water molecule and the positive side of the other water molecule form hydrogen bonds. Section 6-3 Water and Solutions
  15. 15. Solutions and Suspensions <ul><li>A solution is a homogenous mixture </li></ul><ul><li>because it has a uniform composition. </li></ul><ul><li>A suspension is a heterogenous mixture </li></ul><ul><li>because it does not have a uniform </li></ul><ul><li>composition and the particles settle out. </li></ul><ul><li>A colloid is also a heterogenous mixture </li></ul><ul><li>because it does not have a uniform </li></ul><ul><li>composition but in a colloid the particles do not settle out. </li></ul>Section 6-3 Water and Solutions
  16. 16. Water – solvent of life <ul><li>The polarity of water makes it </li></ul><ul><li>an excellent </li></ul><ul><li>solvent. </li></ul><ul><li>A solution is a mixture of </li></ul><ul><li>substances that is the same </li></ul><ul><li>throughout. </li></ul><ul><li>The solvent is the substance </li></ul><ul><li>in greater quantity in a </li></ul><ul><li>solution. </li></ul><ul><li>The solute is the substance </li></ul><ul><li>that dissolves in the solvent. </li></ul>
  17. 17. Acids and Bases <ul><li>Substances that release Hydrogen (H + ) ions </li></ul><ul><li>when they are dissolved in water are called acids. </li></ul><ul><li>Substances that release Hydroxide (OH - ) </li></ul><ul><li>ions when they are dissolved in water are </li></ul><ul><li>called bases. </li></ul>
  18. 18. pH <ul><li>The amount of H + or OH - ions in a solution </li></ul><ul><li>determines the strength of an acid or base. </li></ul><ul><li>pH measures the concentration of H+ </li></ul><ul><li>ions in a solution. </li></ul><ul><li>Acidic solutions have pHs lower than 7 </li></ul><ul><li>Basic solutions have pHs higher than 7 </li></ul><ul><li>A pH of 7 is neutral (distilled water) </li></ul>
  19. 19. pH and Buffers <ul><li>A buffer is a mixture that can react with </li></ul><ul><li>acids or bases to keep the pH in a particular </li></ul><ul><li>range. </li></ul>
  20. 20. The Building Blocks of Life <ul><li>Organic chemistry is the study of organic </li></ul><ul><li>compounds containing carbon. </li></ul><ul><li>Carbon has four outer electrons and so can </li></ul><ul><li>form four covalent bonds with other atoms. </li></ul>
  21. 21. Macromolecules <ul><li>Macromolecules are large molecules made by joining smaller organic molecules together. </li></ul><ul><li>Polymers are made of repeating units of monomers. </li></ul>Section 6-4 The Building Blocks of Life Monomer Polymers
  22. 22. <ul><li>Carbohydrates and </li></ul><ul><li>Lipids provide structure </li></ul><ul><li>and support, Nucleic </li></ul><ul><li>acids store and </li></ul><ul><li>communicate genetic </li></ul><ul><li>information, while </li></ul><ul><li>Proteins provide a wide </li></ul><ul><li>variety of functions. </li></ul>The four major categories of macromolecules are Carbohydrates, Lipids, Proteins and Nucleic Acids. <ul><li>Tree of Life Macromolecules </li></ul>
  23. 23. Carbohydrates <ul><li>Carbohydrates contain Carbon, Hydrogen </li></ul><ul><li>and Oxygen. </li></ul>Simple sugars like Glucose are called monosaccharides . Two simple sugars joined together are called a disaccharide. Ex: Sucrose. Many sugars covalently connected in a chain are called a polysaccharide . Polysaccharides : Glycogen Cellulose Chitin
  24. 24. Lipids <ul><li>Lipids are made mostly of Carbon and </li></ul><ul><li>Hydrogen. The monomers are called fatty acids. </li></ul><ul><li>Lipids are non-polar molecules like fats and </li></ul><ul><li>oils. </li></ul><ul><li>Saturated fatty acids have </li></ul><ul><li>no double bonds in the chain. </li></ul><ul><li>Unsaturated fatty acids </li></ul><ul><li>have one or more </li></ul><ul><li>double bonds in the chain . </li></ul>Section 6-4 The Building Blocks of Life
  25. 25. Phospholipids and Steroids <ul><li>A special lipid called a phospholipid is </li></ul><ul><li>important for cell membranes. </li></ul><ul><li>Other lipids are called steroids </li></ul><ul><li>and include cholesterol and </li></ul><ul><li>hormones like estrogen and </li></ul><ul><li>testosterone. </li></ul>
  26. 26. Proteins <ul><li>Proteins are chains of monomers called </li></ul><ul><li>amino acids held together by peptide </li></ul><ul><li>bonds . </li></ul><ul><li>Proteins contain Carbon, Nitrogen, </li></ul><ul><li>Hydrogen, Oxygen and sometimes Sulfur. </li></ul><ul><li>There are 20 different amino acids. </li></ul>
  27. 27. Proteins <ul><li>The many shapes formed by proteins allow </li></ul><ul><li>proteins to provide functions ranging from </li></ul><ul><li>support and transport to communications , </li></ul><ul><li>speeding up reactions and control of cell </li></ul><ul><li>growth. </li></ul>Proteins can form a variety of 3-dimensional structures.
  28. 28. Nucleic Acids <ul><li>Nucleic Acids are made of monomers called </li></ul><ul><li>nucleotides. </li></ul><ul><li>Nucleic acids are made of Carbon, Nitrogen, </li></ul><ul><li>Oxygen, Phosphorus and Hydrogen. </li></ul><ul><li>Nucleic Acids like DNA and RNA store </li></ul><ul><li>genetic information. </li></ul>

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