clinical anatomy and physiology chapter 2 Chemical Basis for Life

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clinical anatomy and physiology chapter 2 Chemical Basis for Life
2014-09-08 01:46:44
clinical anatomy physiology chapter Chemical Basis Life

clinical anatomy and physiology chapter 2 Chemical Basis for Life
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  1. What is an element?
    An element is matter that cannot be divided by ordinary chemical processes into another substance.
  2. What is a chemical symbol?
    A chemical symbol uses a letter or letters to refer to elements. Chemical symbols are derived from the element’s name in English, Latin, or Greek.
  3. Name the three subatomic particles.
    Proton, neutron, and electron
  4. What is the electrical charge of each particle?
    Protons have a positive electrical charge, neutrons have no electrical charge, and electrons have a negative electrical charge.
  5. Which particles are in the nucleus of an atom?
    Protons and neutrons
  6. How many electron shells would an atom with four electrons have? ?
  7. What is a molecule?
    Molecules are atoms joined together by chemical bonds.
  8. How does an ionic bond differ from a covalent bond?
    A covalent bond is the bond formed when atoms share electrons. An ionic bond is formed when electrons are transferred from one atom to another.
  9. In what circumstance is a hydrogen bond commonly used?
    Hydrogen bonds are formed mostly between molecules (for example, between water molecules) and act to stabilize the solution. Hydrogen bonding is key to water’s unique properties as a universal solvent and a medium for the life processes. Hydrogen bonds can also form between parts of the same molecule. This works to stabilize and hold the shape of large, complex molecules such as proteins and DNA.
  10. What is a chemical reaction?
    A chemical reaction is a change or transformation in a substance during the formation or breaking of chemical bonds.
  11. What are the three types of chemical reactions?
    • Synthesis reaction: A new, more complex chemical is made from multiple, simpler chemicals.
    • Decomposition reaction: A complex substance breaks down into its simpler parts.
    • Exchange reaction: Certain atoms are exchanged between molecules. It is a combination of a synthesis and a decomposition reaction.
  12. The process of catabolism uses which type of chemical reaction?
    Decomposition reaction
  13. What factors influence the rate of chemical reactions?
    The rate of a chemical reaction is influenced by: (1) the availability of the reactants, referred to as the concentration of reactants. The more reactants that are available, the more likely they will come in contact and be able to react with one another. (2) The temperature of the environment. When the temperature increases, the speed of molecular movement increases and the chance of molecules meeting improves. Temperature also increases the velocity at which the reactants meet and the velocity provides the energy for the reaction. (3) Activation energy is the energy required for the reaction to happen. Some reactions have a higher activation energy and require an input of more energy for the reaction to occur. These reactions will occur at a slower pace. (4) Certain reactions require the presence of a catalyst. In living organisms, catalysts are usually special proteins that hold the reactants together so they may interact. The catalyst-protein is not destroyed or used up by the reaction, and the reaction speed is increased when there are more catalyst proteins present. These special catalyst-proteins are called enzymes.
  14. What is the difference between organic and inorganic compounds?
    Organic compounds are molecules that contain hydrocarbon groups (hydrogen and carbon) and usually are covalently bonded. Inorganic molecules do not contain hydrocarbon groups. They often have ionic bonding.
  15. Are only organic compounds necessary for life?
    No. Both organic and inorganic compounds are necessary for life on earth.
  16. What are the three types of inorganic molecules that are important for life?
    Water, salts, and acids and bases
  17. What are the four types of organic molecules that are important for life?
    Carbohydrates, lipids, proteins, and nucleic acids
  18. Why is water called a “polar” molecule?
    It has a slight positive charge in the area of the hydrogen atoms and a slight negative charge in the area of the oxygen atom. This polarity allows water molecules to form hydrogen bonds with each other and with other polar molecules.
  19. What are the four properties of water that make it so necessary for life?
    (1) Water is the universal solvent. (2) Water is an ideal transport medium. (3) Water has a high heat capacity and a high heat of vaporization. (4) Water is used for lubrication.
  20. How is an ion different from an atom?
    Atoms are neutral. They contain the same number of protons as electrons. An ion is an electrically charged particle produced by either removing electrons from a neutral atom to yield a positive ion or adding electrons to a neutral atom to yield a negative ion.
  21. What is an electrolyte?
    Electrolytes are substances that have the ability to transmit an electrical charge.
  22. What are some examples of electrolytes?
    Sodium, potassium, and calcium are examples of electrolytes.
  23. Which type of compound is known as a proton donor, acid or base?
  24. What does pH measure?
    The pH of a solution is a measure of its acidity or alkalinity.
  25. Is a solution with a pH of 8.5 acidic or basic?
  26. How does a weak acid act as a buffer?
    It helps the cell maintain a neutral pH by not allowing excessive hydrogen or hydroxyl ions to accumulate. In water, a weak acid will initially ionize into: (1) free hydrogen (H+) ions, (2) a weak base product, and (3) remaining intact weak acid molecules. The pH of the solution is not changed much because some of the chemical remains in acid form and some in the form of a weak base.
  27. What three elements are found in all carbohydrates?
    Carbon, hydrogen, and oxygen
  28. What is the name of a simple sugar?
  29. What process joins multiple simple sugars?
    Dehydration synthesis
  30. What is another name for a complex, multiunit carbohydrate?
  31. What three elements are found in all lipids?
    Carbon, hydrogen, and oxygen
  32. Which atom makes up the backbone of all lipid molecules?
    Carbon, hydrogen, and oxygen
  33. Which lipids are polar, neutral fats or phospholipids?
  34. What is the function of lipids in the body?
    Lipids are used in the body for energy and are stored in fat for future energy needs. Lipids also serve as chemical messengers in the form of some hormones.
  35. What element is found in all proteins that is not found in carbohydrates or lipids?
  36. What are the building blocks for proteins?
    Amino acids
  37. What is the name of the bond holding two amino acids together?
    Peptide bond
  38. What is a peptide?
    A peptide is a molecule consisting of two or more amino acids in which the carboxyl group of one acid is linked to the amino group of the other.
  39. How does an enzyme work?
    Enzymes speed up or catalyze chemical reactions without being destroyed or altered. Enzymes are specific to the reaction they catalyze and the substrates (the substances they act upon) they use.
  40. How does a nucleotide differ from a nucleic acid?
    Nucleotides are the building blocks of nucleic acids.
  41. What three parts compose a nucleotide?
    Nucleotides are composed of a nitrogenous base, a 5-carbon (pentose) sugar, and a phosphate group.
  42. How many nitrogenous bases are there?
    There are five nitrogen bases: adenine (A), guanine (G), cytosine (C), uracil (U), and thymine (T).
  43. Explain the structure of DNA.
    DNA molecules consist of two parallel strands of the nucleotides A, G, C, and T. The strands are connected by hydrogen bonds between the nitrogenous bases. Each nitrogenous base can only hydrogen-bond with one other specific nitrogenous base. Adenine can bond only with thymine, and guanine can bond only with cytosine. The two strands of bonded nucleic acid twist around each other in a spiral called a double helix. The order of the nucleotides is unique to each individual and is carried in every cell of the individual.
  44. Why is DNA important to life?
    DNA is the molecule that contains all the instructions needed by the cell to build protein. These instructions determine the shape and function of every tissue in the body and therefore the shape and function of the living organism.
  45. How does an ATP molecule differ from a nucleotide?
    ATP is an RNA nucleotide containing the nitrogen base adenine with two additional phosphate groups attached.
  46. How does an ATP molecule supply a cell with energy to do work?
    As a nutrient (for example, glucose) is catabolized, the energy created is stored in ATP molecules. ATP stores this energy in the bonds between its phosphate groups. When these bonds are broken, that energy is released from the ATP molecule. To use the energy stored in ATP, enzymes must move the terminal phosphate group to another molecule. The receiving molecule is then called phosphorylated and temporarily has energy to do some work. During this process the ATP molecule loses a phosphate group and becomes ADP. Another phosphate group can be used, resulting in the creation of a molecule of AMP. As more glucose and other nutrients are metabolized, phosphate groups are joined to AMP creating a renewed source of ATP.