Chemical constituents of_cells


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Chemical constituents of_cells

  1. 1. Chemical Constituents of Cells Chapter 2: Chemical Basis of Life Unit 1: Levels of Organization
  2. 2. Chemicals  <ul><li>Chemicals that enter into metabolic reactions or are produced by them can be divided into two large groups. </li></ul><ul><ul><li>Organic Substances </li></ul></ul><ul><ul><li>Inorganic Substances </li></ul></ul>
  3. 3. Let Us Compare! <ul><li>Inorganic Substances : dissolve in water or react with water to release ions </li></ul><ul><ul><li>They are electrolytes </li></ul></ul><ul><li>Organic Substances : can dissolve in water, but are more likely to dissolve in organic liquids like ether or alcohol. </li></ul><ul><ul><li>They are non-electrolytes because they usually do not release ions </li></ul></ul>
  4. 4. Inorganic Substances <ul><li>There are 4 key inorganic substances common in cells: </li></ul><ul><ul><li>Water </li></ul></ul><ul><ul><li>Oxygen </li></ul></ul><ul><ul><li>Carbon Dioxide </li></ul></ul><ul><ul><li>Salts </li></ul></ul>
  5. 5. Water <ul><li>This is the most abundant compound in living material and accounts for roughly 2/3 of the weight of an adult human. </li></ul><ul><ul><li>It is a major component of blood and other body fluids (including those within cells) </li></ul></ul>
  6. 6. What Does H 2 O Do? <ul><li>It is an important solvent , allowing for most biochemical reactions to occur in water. </li></ul><ul><ul><li>Plays a key role in moving chemicals within the body. </li></ul></ul><ul><ul><li>The aqueous portion of blood!!! </li></ul></ul>
  7. 7. What Does H 2 O Do? <ul><li>Has a high specific heat </li></ul><ul><ul><li>It helps to regulate body temperature by absorbing and transporting heat . </li></ul></ul><ul><ul><li>When sweat evaporates, it takes heat with it </li></ul></ul><ul><ul><li>Blood moves heat around the body </li></ul></ul>
  8. 8. Water <ul><li>All the special properties of water are due to the H-bonds between water molecules </li></ul>
  9. 9. Oxygen <ul><li>Molecules of oxygen enter the body through the respiratory organs and are transported throughout the body by blood. </li></ul><ul><ul><li>Cellular organelles use oxygen to release energy from the sugar glucose and other nutrients. </li></ul></ul><ul><ul><li>The released energy drives the cell’s metabolic activities. </li></ul></ul>
  10. 10. Carbon Dioxide <ul><li>It is produced as a waste product when cellular respiration releases energy </li></ul><ul><ul><li>Exhaled from the lungs. </li></ul></ul><ul><ul><li>Reacts with water to form carbonic acid </li></ul></ul>
  11. 11. Salts <ul><li>Salts are actually a group of inorganic compounds. </li></ul><ul><ul><li>Provide many ions for important metabolic processes, including transport of substances into and out of the cell, muscle contractions, and nerve impulses. </li></ul></ul>
  12. 12. Organic Substances <ul><li>These are the four major macromolecules (polymers) of life! </li></ul><ul><ul><li>Carbohydrates </li></ul></ul><ul><ul><li>Lipids </li></ul></ul><ul><ul><li>Proteins </li></ul></ul><ul><ul><li>Nucleic Acids </li></ul></ul>
  13. 13. Carbohydrates <ul><li>This molecule provides most of the energy that cells require to participate in metabolism. </li></ul><ul><ul><li>Supply materials to build cellular structures and are stored as reserve energy supplies </li></ul></ul>
  14. 14. More Carbs <ul><li>These molecules contain atoms of carbon, hydrogen, and oxygen in a 1:2:1 ratio. </li></ul><ul><ul><li>Example: glucose (C 6 H 12 O 6 ) </li></ul></ul>
  15. 15. Carbohydrate Structure <ul><li>Sugars with 6 carbon atoms are called simple sugars or Monosaccharides . </li></ul><ul><ul><li>Most in the shape of a ring </li></ul></ul><ul><ul><li>Glucose and fructose </li></ul></ul>
  16. 16. Carbohydrate Structure <ul><li>Complex carbohydrates involve the linking of 2 or more simple sugars. </li></ul><ul><ul><li>Disaccharides (double sugars) each contain two simple sugar building blocks </li></ul></ul><ul><ul><ul><li>Two rings bonded together </li></ul></ul></ul><ul><ul><ul><li>Sucrose and lactose </li></ul></ul></ul>
  17. 17. Carbohydrate Structure <ul><ul><li>Polysaccharides are made up of 3 or more simple sugar building blocks </li></ul></ul><ul><ul><ul><li>Hundreds (or thousands) of rings bonded together </li></ul></ul></ul><ul><ul><ul><li>Plant starch and animal (human) glycogen </li></ul></ul></ul>
  18. 18. Lipids <ul><li>Lipids are organic substances that are insoluble in water. </li></ul><ul><ul><li>Include fats, phospholipids, and steroids. </li></ul></ul><ul><ul><li>Fatty acids are the building blocks </li></ul></ul><ul><ul><li>All of these compounds have vital functions in cells. </li></ul></ul>
  19. 19. Fats <ul><li>Used primarily to store energy for cellular activities. </li></ul><ul><ul><li>Provide about 3x more energy (gram for gram) than carbohydrate molecules. </li></ul></ul><ul><li>3 fatty acid molecules and 1 glycerol combine to produce a single fat ( Triglyceride ) molecule. </li></ul>
  20. 21. Fat Types <ul><li>Fatty acid molecules differ in the length of their carbon atom chains, and the way the carbon atoms combine. </li></ul><ul><ul><li>Saturated </li></ul></ul><ul><ul><li>Unsaturated </li></ul></ul><ul><ul><li>Polysaturated </li></ul></ul>
  21. 22. Saturated Fats <ul><li>Fatty acids that contain carbon atoms all joined by single carbon-carbon bonds. </li></ul><ul><ul><li>Each carbon atom is bound to as many hydrogen atoms as possible, and is thus “saturated” with hydrogen atoms. </li></ul></ul><ul><ul><li>These fats are solid at room temp. </li></ul></ul>
  22. 23. Unsaturated Fats <ul><li>These fatty acids are not bound by the maximum number of hydrogen atoms possible because they contain one or more double-bonds between carbon atoms. </li></ul><ul><ul><li>Fatty acid molecules with many double-bonded carbon atoms are called Polyunsaturated </li></ul></ul><ul><ul><li>These fats are liquid at room temp. </li></ul></ul>
  23. 25. Health Connection <ul><li>A diet high in saturated fats increases the change of developing Atherosclerosis , which obstructs arteries. </li></ul>
  24. 27. Phospholipids <ul><li>The main constituent of the cell membrane </li></ul><ul><li>Two fatty acids </li></ul><ul><li>Glycerol </li></ul><ul><li>Phosphate head </li></ul>
  25. 28. Phospholipids <ul><li>Heads are polar </li></ul><ul><li>Two tails are nonpolar </li></ul><ul><li>Create lipid bilayer </li></ul>
  26. 29. Steroids <ul><li>Complex structures that include four connected rings of carbon atoms. </li></ul><ul><ul><li>The most important steroids are cholesterol (occurs in body cells, and is used to synthesize other steroids) and sex hormones (estrogen, progesterone, and testosterone) </li></ul></ul>
  27. 31. Proteins <ul><li>Composed of carbon, hydrogen, oxygen, nitrogen, and sulfur. </li></ul><ul><ul><li>Proteins serve as structural materials, energy sources, and hormones. </li></ul></ul><ul><ul><li>Some proteins combine with carbs ( Glycoproteins ) and function on cell surfaces as Receptors </li></ul></ul><ul><ul><li>Some acts as Antibodies in your immune response. </li></ul></ul><ul><ul><li>Some act as catalysts and are called Enzymes </li></ul></ul>
  28. 32. Proteins Continued <ul><li>The building blocks of proteins are Amino Acids </li></ul><ul><ul><li>20 different kinds of amino acids occur commonly in the proteins of life </li></ul></ul><ul><ul><ul><li>Proteins are formed by joining amino acids with peptide bonds to form a chain (polypeptide chain) that varies in length from less than 100 to more than 5,000 amino acids. </li></ul></ul></ul><ul><ul><ul><ul><li>A human body has more than 100,000 different types of proteins. </li></ul></ul></ul></ul>
  29. 33. Protein Structure <ul><li>Proteins have several levels of structures: Primary, Secondary, and Tertiary levels. Animation </li></ul><ul><ul><li>Hydrogen and covalent bonding between atoms in different parts of the polypeptide give the final protein a complicated 3-D shape or Conformation . </li></ul></ul><ul><ul><ul><li>THE CONFORMATION OF A PROTEIN DETERMINES ITS FUNCTION!!! </li></ul></ul></ul>
  30. 35. Examples of Conformation <ul><li>Long and fibrous: Keratin protein forms hair, and Fibrin knits a blood clot. </li></ul><ul><ul><li>Many proteins are globular and function as enzymes, ion channels, carrier proteins, or receptors. </li></ul></ul><ul><ul><ul><li>Examples: Myoglobin and hemoglobin </li></ul></ul></ul>
  31. 36. A Change in Shape <ul><li>When hydrogen bonds break, the unique shape of the protein is altered </li></ul><ul><ul><li>Called Denatured . </li></ul></ul><ul><ul><li>This causes the protein to lose its special properties. </li></ul></ul><ul><ul><ul><li>Example: heat denatures the protein in egg white (albumin), changing it from a liquid to a solid. </li></ul></ul></ul>
  32. 37. Nucleic Acids <ul><li>Nucleic Acids act as the molecules of heredity. </li></ul><ul><ul><li>Contain atoms of carbon, hydrogen, oxygen, nitrogen, and phosphorous. </li></ul></ul><ul><ul><li>The building blocks of nucleic acids are Nucleotides </li></ul></ul>
  33. 39. Types of Nucleic Acids <ul><li>RNA (ribonucleic acid) is composed of molecules whose nucleotides contain the sugar ribose </li></ul><ul><ul><li>Single stranded molecule used in protein synthesis </li></ul></ul><ul><li>DNA (deoxyribonucleic acid) is composed of molecules whose nucleotides contain the sugar deoxyribose. </li></ul><ul><ul><li>Double stranded molecule that stores the information needed to synthesize protein molecules. </li></ul></ul>
  34. 41. Clinical Connection <ul><li>The discovery of Prion Proteins overturned the long-held idea that a protein can only assume one conformation. </li></ul><ul><ul><li>A prion can assume up to a dozen different conformations. </li></ul></ul><ul><ul><ul><li>Some prions are infectious, and can bind to “normal” proteins converting them into infectious prions as well. </li></ul></ul></ul>
  35. 42. Abnormal Prions <ul><li>Abnormal prions cause diseases called Transmissible Spongiform Encephalopathies . </li></ul><ul><ul><li>More than 80 species of mammals are subject to these diseases. </li></ul></ul><ul><ul><ul><li>Examples: bovine spongiform encephalopathy (mad cow disease) and Creutzfeldt-Jakob disease </li></ul></ul></ul><ul><ul><ul><ul><li>Both turn parts of the brain into spongy masses with steady loss of mental function. </li></ul></ul></ul></ul>