Bio Exam I

  1. All, without exception, nucleic acids contain which five elements?
    • C
    • H
    • O
    • P
    • N
  2. Why do the rings in nucleic acids differ from others?
    they contain nitrogen
  3. What is the function of 1-6 linkages?
    branching out
  4. What linkage does amylose have? amylopectin? glycogen?
    • 1-4 alpha linkages
    • 1-6 alpha linkages
    • 1-6 and 1-4
  5. What is the catch with structural polysaccharides?
    they cannot be hydrolyzed by the organisms that make them
  6. What are the two shapes of proteins?
    • fibrous (relatively straight and long)
    • - usually just primary, secondary, and quaternary
    • globular (spherical)
    • - has all four levels
  7. What are the three classification systems of proteins?
    • based on:
    • - levels of structure
    • - composition
    • - function
  8. What are the protiens based on levels of structure?
    fibrous proteins: exhibit primary and secondary structure; somes quaternary; insolubale; stable; form tough structures

    globular proteins: exhibit primary, secondary, tertiary, and sometimes quaternary; arranged so that the R-groups are on the inside and the ones on the outside are hydrophilic
  9. What are proteins based on composition?
    • simple proteins: composed of only amino acids in a polypeptide chain
    • Conjugated proteins: composed of one or more polypeptide chains plus a non-amino acid component called a co-factor; the cofactor has to be there for the protein to function
  10. What are proteins based on function?
    • structural
    • contractole (muscle)
    • defensive
    • transport
    • hormones
    • toxins
    • storage
    • receptor proteins
    • enzymes
  11. What are the disaccharides?
    • maltose= glucose + glucose
    • lactose= galactose + glucose
    • sucrose= fructose + glucose
  12. What does sucrose do?
    • transform form of sugar in the plant
    • -storage of carbs in larger sizes
  13. what is lactose?
    milk sugar
  14. What are oligosaccharides?
    • a short chain of 3 - 100s of monosaccharide molecules joined together via glycosidic bonds
    • - usually linked to some other molecule (lipid, protein)
    • - most common location: poking out surface of plasma membrane
  15. What are the two basic functions of oligosaccharides?
    • recognition
    • adhesion
  16. What is linkage?
    a designation of which carbon atoms in adjacent monosaccharide subunits are bonded together; can also indicate whether in alpha or beta form
  17. What are the two forms of starch?
    • amylose 
    • amylopectin
  18. What are examples of lipids?
    • fats
    • oils
    • waves
    • phospholipids
    • carotenoids
    • steroids
  19. What are the components of phospholipids?
    • one glycerol
    • two fatty acids
    • one phosphate (may/ may not include an organic group attached to the phosphate)
  20. What are the three classifacations of amino acids on basid of chemical characteristics of the R group?
    • nonpolar
    • polar but uncharged
    • electrically charged (acidic or basic)
  21. What do proteins differ in?
    • - total  number of amino acids (size); each type of protein contains a specific number of amino acids
    • - relative quantities of each specific type of amino acid
    • - specific sequence (order) of amino acids
    • - specific 3D shape
  22. What are the subunits of DNA?
  23. What is the 5' end?
    end where the phosphate group is not attached to another nucleotide
  24. What is a 3' end?
    end where sugar of nucleotide is not linked to another nucleotide
  25. How many hydrogen bonds form with adenine?
  26. How many hydrogen bonds form between guanine and cytosine?
  27. Who proposed the structure of DNA?
    • alpha double helix
    • Watson and Crick (+ Rosalind Franklin)
  28. DNA molecules differ in?
    • number of base pairs
    • relative quantities of each specific base pair
    • specific sequence (order) of base pairs
  29. What is the function of DNA?
    stores genetic info in the sequence of genes
  30. What are the alternative forms of DNA?
    • single stranded v. double stranded
    • linear vs. circular
    • 3D structures
  31. What is the difference between organic and inorganic?
    • organic contains carbon
    • inorganic may contain carbon iin a very energy poor state
  32. All chemical reactions in the cell occur where the reactants __.
    dissolve in water
  33. Why is water a very good solvent?
    • its a polar molecule
    • Oxygen has a partial negative charge, while hydrogen has a partial positive charge, enabling attraction to other compounds.
  34. What are two other important functions of water?
    • tranfsport
    • it acts as a lubricant to decrease friction
  35. Hydrolysis can only occur if __.
    the molecule is combined through dehydration reactions.
  36. What are the benefits of linking monosaccharides togehter?
    decreases amount of material in cell, lowering the concentration of dissolved material in the cell
  37. What do lipids consist of?
    Which are dominant?
    • H
    • O
    • and sometimes P and N
  38. Lipids are insoluble in __, but soluble in __.
    • water
    • organic solvents
  39. In fats and oils, what does glycerol not contain? How many carbons are usually present in hydrocarbon chains?
    • double bond
    • 14-22
  40. True or False: If a molecule has even a slight charge, it will dissolve in water.
  41. What is the function of the phosphate group in a phospholipid?
    hydrocarbon tails?
    • interact well water water due to charge (polar/ hydrophilic)
    • tails are hydrophobic and are away from the water
  42. What are steroids?
    four-fused rings of carbon; the sharing of carbons enables fusion
  43. Animal hormones are one of two types:
    • steroids 
    • proteins
  44. What makes steroids different?
    the attachments to the ring
  45. What is the solubility characteristic of steroids?
    • rings don't dissolve in water (hydrophobic)
    • the only hydrophilic substance is the -OH group
  46. Explain cholesterol/
    • cholesterol: major function of animal membranes ONLY
    • liver makes it
    • starting point for making other steroids
    • animal hormones
    • vitamines
  47. What are the elements in proteins?
    • C
    • H
    • N
    • O
    • and sometimes sulfur
  48. Peptide bonds link two __. Are they straight or branched?
    • amino acids
    • straight
  49. Which amino acid usually starts the chain?
  50. How do the ends of the chains in polypeptides differ?
    • N-terminus
    • C- terminus
  51. Explain the linkages in each stage of protein structure?
    • Primary: carboxyl and amino acid (peptide bond)
    • Secondary: hydrogen bonding between carboxyl and amino acid
    • Tertiary: bonds between the side chains of same polypeptide, giving it an folded, 3D shape
    • Quaternary: bonds between two or more polypeptide chains
  52. Do all proteins have:
    primary structure?
    secondary structure?
    tertiary structure?
    • yes
    • yes
    • no
    • no
  53. In DNA, which components are responsible for bining the nucleotide together?
    phosphates and sugar--> phosphodiester linkage
  54. What are the purines?
    adenine and guanine
  55. What are the pyrimidines?
    cytosine and thymine
  56. Exlain:
    - single stranded DNA?
    - double stranded DNA?
    • viruses usually contain
    • most common form
  57. Explain:
    - linear DNA.
    circular DNA.
    • Linear common in most organisms
    • Bacteria, mitochondria, and chloroplasts contain circular DNA.
  58. What are the 3D Structures of DNA?
    • B-DNA: most common; right-handed helix/ set number of base pairs per turn
    • A- DNA: right- handed helix; higher set of base pairs per turn exists
    • Z- DNA: same base pair number per turn as B-DNA; very temporary; left-handed helix
Card Set
Bio Exam I