Microbiology Ch 2

  1. Valence
    The combining capacity of an atom - the number of extra or missing electrons in it outermost shell
  2. Ionic Bond
    attraction between two ions of opposite charge that holds them together to form a stable molecule

    cation - + charged Ion

    anion - - charged ion
  3. Covalent Bond
    formed when two atoms share one or more pairs of electrons - strong bonds
  4. Hydrogen Bond
    a hydrogen atom that is covalently bonded to one oxygen or nitrogen is attracted to another oxygen or nitrogen - weak bonds - don't form molecules
  5. chemical reactions
    involve making or braking of bonds between atoms - involved energy

    when chemical bonds are broken - energy released

    when chemical bonds make - energy used
  6. Endergonic reactions

    Exergonic reactions
    Endergonic reactions - absorb more energy than they release (energy in)

    Exergonic reactions - release more energy than they absorb (energy out)
  7. Synthesis reactions
    decomposition reactions
    Synthesis reactions - to put together - to form new bonds (dehydration synthesis)

    anabolism - anabolic reactions - synthesis reactions - building large molecules from smaller ones

    catabolism - catabolic reactions - hydrolysis decomposition reactions - tear large molecules down into smaller ones

    decomposition reaction - decomposition hydrolysis - to break down into smaller parts
  8. Why is water so important to life?
    It is polar - oxygen is electronegative and pulls the electrons toward it

    • partial (-) charge = oxygen end
    • partial (+) charge = hydrogen end
  9. Functions of water (2)
    • 1. Solvent - its polarity makes it a good solvent - dissolves charged and polar structures
    • - - solute - dissolving substance - things dissociate because they are attracted to the polarity of the water

    2. Temperature Buffer - it takes a lot of heat (energy) to break the hydrogen bonds in water to go from liquid to stream (compared to liquids that dont have hydrogen bonds)
  10. Organic compounds
    always contain carbon and hydrogen
  11. inorganic molecule
    usually lack carbon - simpler structure than organic compounds
  12. pH

    human pH
    power or potential of hydrogen - the amount of H+ in a solution -log10[H+] each whole number represents a tenfold change from the previous concentration

    Pure water has a pH of 7 and is considered neutral because the concentrations of dissociated H+ and OH- are equal

    Human pH is 7.35 - 7.45 (slightly basic)
  13. acid
    • substance that dissociates into H+ and anions (-)
    • hydrogen ions negatively charged ions

    Proton donor H+

    HCL = H+ + Cl-
  14. base (alcaline)
    • substance that dissociates into OH- and cations (+)
    • hydroxide ions and positively charged ions

    Proton acceptors

    NaOH = OH- + Na+
  15. salt
    • substance that dissociates into anions and cations - neither of which are H+ and OH-
  16. buffer
    compounds that keep the pH from changing drastically
  17. Carbohydrates
    made of?
    monomer is monosaccharide (glucose, fructose)

    Made of C, H. O (NO nitrogen)

    Function is to fuel cell activities with ready source of energy (glucose)
  18. disaccharide
    • di = 2 sugars (monosaccharides) sucrose (table sugar)
    • Poly = many monosaccharides

    glycogen = storage unit for glucose in humans and animals

    cellulose = polysaccharide that is the main component of plant cell walls - most abundant carbohydrate on earch

    chitin - polysaccharide that makes up part of plant cell walls and the exoskeletons of lobsters, crabs, and insects

    starch - plant form of glucose storage
  19. macromolecules - building
    dehydration sysnthsis - building - water released

    hydrolysis - water consumed
  20. Lipids
    made of?
    saturated fat
    unsaturated fat
    • Fat- - they are non-polar (don't dissolve in water)
    • monomers are glycerol and fatty acids
    • Made of C, H, O (no nitrogen)

    saturated fat - there are no double bonds - all the carbons are "saturated" with hydrogens - solid at room temp

    unsaturated fat - double bonds so all carbons are not filled with hydrogen - liquid at room temp
  21. structure and function of:
    • triglycerides - one glycerol (alcohol) molecule attached to 3 (tri) fatty acid chains
    • function as energy storage (adipose tissue) in humans

    • phospholipods - complex lipid - one glygerol, two fatty acids, and a phosphate group
    • function as an important part of the plasma membrane -phospholipid bilayer - hydrophillic heads out and hydrophobic tails in

    • steriods - cholesterol - four interconnected carbon rings
    • function as a component of the plasma membrane of animal cells
  22. proteins
    made of?
    monomer is amino acids

    made of C, H, O, N and S

    20 different amino acids - each has an amino group, a carboxyl (acid ) group, and an R group (which contain nitrogen)
  23. peptide bond
    dehydration synthesis (water released) between two amino acids - forms a covalent bond (very strong)
  24. 4 levels of protein structure

    primary structure - unique sequence of amino acids held together by peptide bonds

    secondary structure - twisting or folding (helix and beta pleated sheets) of the polypeptide chain - shape held by hydrogen bonds between the amino acids

    tertiary structure - 3D shape of the protein - fold with hydrophobic portions to the inside - shape held by hydrogen bonds between side groups and ionic bonds between oppositely charged side groups, and disulfide bridges (if the aa cysteine is present) Disulfide bridges are covalent bonds between two cysteine molecules.

    quarternary structure - two or more peptide chains that function as a single unit - also held together by hydrogen bonds, ionic bonds, and disulfide bridges.

    denaturation - if a protein is in hostile environment (temp, pH, salt concentration) its shape changes and it is no longer functional
  25. 8 Functions of proteins
    • 1. Structural proteins - collagen, keratin, elastin
    • 2. Enzymes - speed up chemical reactions
    • 3. Transporter proteins - move chemicals through membrane or in blood
    • 4. Contractile proteins - actin and myosin
    • 5. Hormones
    • 6. Antibodies - immune function
    • 7. Clotting factors - work w/ platelets to stop bleeding
    • 8. Organelles - cytoskeleton, flagella
  26. conjugated protein
    conjugated proteins are make of amino acids and other organic or inorganic components

    • glycoproteins - contain sugar
    • nucleoproteins - nucleic acids
    • metalloproteins - metal atoms
    • lipoproteins - lipids
    • phosphoprotiens - phosphate group
  27. Nucleic Acids
    3 types of Nucleic Acids
    made of?
    parts of a nucleotide
    Base Pairs
    monomer is a nucleotide

    DNA, RNA, and ATP

    made of C, H, O, N, P

    • nucleotide
    • 1. pentose (5 carbon) sugar -ribose or deoxyribose
    • 2. phosphate group
    • 3. nitrogenous base (contains nitrogen)
    • - purine = Guanine and Adenine
    • -pyrymadines = Cytosine, Uracil, Thymine

    • Base Pairs
    • A-T Held together with 2 hydrogen bonds
    • C-G Held together with 3 hydrogen bonds
  28. DNA
    3 Types of RNA
    • DNA - double helix -sides alternate sugar and phosphate groups - rungs of the latter are nitrogen containing bases
    • the nucleotide rungs form genes

    RNA - single stranded - contains ribose instead of deoxyribose - contains Uracil instead of Thymine

    • 1. mRNA - messenger RNA
    • 2. rRNA - ribosomal RNA
    • 3. tRNA - transfer RNA

    ATP - cell energy currency - make of nitrogenous base adenine + ribose + 3 phosphate groups

    energy is stored in the phosphate bonds
Card Set
Microbiology Ch 2
Exam review from Micro Ch 2 - Chemistry