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2013-05-12 19:04:19
bio biochem

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  1. What is the most frequently occuring chemical elements in living things?
    • Carbon
    • Hydrogen
    • Oxygen
    • Nitrogen
  2. What variety of other elements are needed by living organisms?
    • sulfur
    • calcium
    • phosphorus
    • iron
    • sodium
    • PICSS
  3. Role of calcium?
    • humans: needed to strengthen bone/teeth
    • influences membrane permeability
    • activator for several enzymes
  4. role sulphur?
    needed for synthesis of 2/20 amino acids
  5. role of phosphorus
    part of phosphate groups in DNA, RNA, ATP and coenzyme molecules, (cell membrane) phospholipids too
  6. role o iron
    animal cells: iron needed structure of heme groups in hemoglobin
  7. role o sodium
    • influences ionic balance cells for osmosis
    • pumped in to cytoplasm to raise solute concentration and cause water to enter
    • animal: sodium used by neurons to transmit nerve impulses
    • plants: helps maintain turgor pressure
  8. Draw and label diagram showing structure water molecule to show ppolarity and hydrogen bond formation and covalent bonds
    • draw second diagram w/ hydrogen bonds
  9. What 3 properties of water make it significant to living organisms?
    • cohesion, solvent properties, thermal properties
    • result of hydrogen bonds
  10. Outline the thermal (3), cohesive, and solvent properties of water
    • cohesion: water molecules stick due to hydrogen bonding
    • solvent properties: universal solvent, polar nature allows many substances to dissolve in water "like dissolves like" (ions, polar molecules like glucose)
    • thermal prop; heat capacity: has large heat capacity, lots of energy needed to raise water temperature, stored heat energy given out when water cooled
    • thermal prop; boiling/freezing point: relatively high boiling point, hydrogen bonds must be broken to change state from liquid to gas; high freezing point, density decreases as it freezes, ice forms at surface first
    • therm prop; cooling effect o evaporation: can evaporate at temp below boiling, hydrogen bonds must be broken, heat enrgy taken fr liquid water = cool down
  11. What are the three uses for water in terms of living organisms?
    • coolant
    • medium for metabolic reactions
    • transport medium
  12. Explain water's significance to living organisms as a transport medium
    • transport medium: cohesion, solvent properties, heat capacity
    • xylem of plants to allow transport columns of water to tops of trees, cohesion and hydrogen bonds
    • solvent=universal solvent b/c polarity dissolving inorganic particles w/ charges, organic substances w/ polar molecules and enzymes
    • allows substances to be dissolved in blood o animals and sap of plants to provide transportation throughout organism
    • large heat capacity allows water to transport heat fr warmer parts of body to cooler
  13. Explain water's significance to living organisms as a coolant
    • evaporation water from leaves (transpiration) and from human sweat =cooling effect
    • water can evaporate at temp below boiling
    • as bonds break, require energy and takes heat fr liquid water cooling down person
  14. Explain water's significance to living organisms as a medium for metabolic reactions
    • solvent property, specific heat capacity
    • most chemical reactions take place between all of the subtances dissolved in water
    • high boiling point/freezing allows it to stay above freezing and below boiling in most places on eath = liquid acts as medium for metabolic reactions
  15. Distinguish between organic and inorganic compounds
    • Organic compound – compounds found in living organisms and contain carbon
    • (except hydrogen carbonates, carbonates, oxides carbon in humans but inorganic CO3 COx HCO3)
    • Inorganic compound – compounds that do not contain carbon
  16. glucose
    • hydroxyl groups from left to right
    • down, up, down, down
    • hexagon, 6 carbons
    • C6H12O6
  17. ribose
    • pentagon
    • two hydroxyls down at bottom
    • C6H12O6
  18. amino acids
    • amine group on one end, carboxyl on other
    • each 20 amino acids has a different r group
    • butterfly
  19. fatty acids
    • carboxy group one end
    • C and three H on other end
    • fishbone
    • forms limited bonds b/c only one functional group
  20. List three examples of each monosaccharides, disaccharides, and polysaccharides
    • Monosaccharides: glucose, galactose,fructose
    • Disaccharides: maltose, lactose, sucrose
    • Polysaccharides: starch, glycogen, cellulose
  21. State a function of glucose, lactose, and glycogen in animals and fructose, sucrose and cellulose in plants
    • animals
    • Glucose: used as energy source for thebody
    • Lactose: sugar in milk, provides energy to new born until they are weaned
    • Glycogen: used as short term energy source stored in muscle and liver
    • plants
    • Fructose: makes fruits sweet, attracts animals to eat fruit and disperse seeds
    • Sucrose: used as energy source for the plant
    • Cellulose: cellulose fibres makes plant wall strong
  22. Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides
    • monosaccharides undergo condensation (remove water) to become disaccharides/polysaccharides
    • glucose + glucose -> maltose + water
  23. between amino  acids and polypeptides
    • condensation joins 2 amino acids to form a dipeptide
    • polypeptide formed when more amino acids added
    • amino acid + amino acid -> dipeptide + water
    • multiple amino acids -> polypeptide + many water molecules
  24. between fatty acids, glycerol and triglycerides
    • 3 fatty acids joined to glycerol by ester bonds
    • three water molec produced
    • no chain formed
    • diglycerid: 2 fatty acid + glycerol
  25. Condensation
    • A reaction in which two molecules combine to form a larger molecule through removal of water
    • one molecule of water produced for each time another subunit is attached
  26. hydrolysis
    • The chemical breakdown of a compound due to addition of water.
    • reverse of condensation
  27. state three functions of lipids
    • Energy storage in the form of fat in humans, and oil in plants
    • Used as heat insulation as fat under skin, reducing heat loss
    • Allow buoyancy (b/c less dense than water) so animals can float in water
  28. Compare use of carbohydrates and lipids in energy storage
    • both can be used as energy storage in living organisms
    • carb for short term storage, lipids for long term
    • lipids contain more energy/g than carbs
    • stores of lipids = lighter than stores o carbs tt contain same amnt energy
    • carbs more easily digested; energy stored released more rapidly
    • due to water solubility, carbs easier to transfer from store
    • carbs polar soluble in water, lipids nonpolar not
    • lipids dont cause problems osmosis in cells due to water solubility
  29. primary structure
    • number and sequence amino acids in polypeptide
    • most polypeptides are 50-1000 amino acids long
    • primary structure determined by nuceotide sequence in a gene in DNA
    • -N-C-C-N-C-C-N-C-C- backbone
    • has r group
  30. significance of primary structure
    • correct sequence of amino acids decides the final conformation and function of the protein
    • changing one could alter final conformation = useless
  31. secondary structure
    • Regular repeating structure
    • α-helices (myosin) and β-pleated sheets (silk protein)
    • stabilized by hydrogen bonds tt form b/twn nearby amino acids in main chain of polypeptide
  32. significance secondary structure
    • Proteins that contain secondary structures will have regions that are cylindrical (α-helices) and/or regions that are planar (β-pleated sheets).
    • coiling and folding o polypeptide chain can form fibrous proteins and contribute to globular protein structure
  33. tertiary structure
    • three-dimensional conformation o polypeptide
    • Occurs as a result of the protein folding
    • stabilized by side chain (R-group)
    • interactions include ionic bonds, hydrogen bonds, hydrophobic interactions, disulfide bridges, strong covalent bonds
    • strongest
  34. significance tertiary structure
    • final shape of polypeptide
    • may make it a functional protein
  35. quaternary structure
    • linking 2 or more polypeptides to form single protein
    • In some cases, some proteins can have a non-polypeptide structure called a prosthetic group.
    • These proteins are called conjugated proteins.
    • haem group in haemoglobin is a prosthetic group.
  36. significance quaternary structure
    makes functional proteins
  37. Examples of quaternary structures
    • insulin
    • collagen
    • hemoglobin: 4 polypeptides + heme group (conjugated protein)
  38. Outline the difference between fibrous and globular proteins w/ reference to two examples o each protein type
    • fibrous and globular = both quaternary structure
    • fibrous: long and narrow in shape; mostly insoluble e.g. collagen, myosin
    • globular: rounded shape, mostly soluble e.g. hemoglobin, insulin