P3 questions DATABASE (part a)

• Outline why vitamins usually need to be obtained from food sources.

  because our bodies cannot synthesized them
• State two factors, other than concentration, that must be controlled for correct metabolic functioning in the cytoplasm of a cell.

  Temperature and pH
• State the general formula of a carbohydrate.

  Cx(H2O)y
• Describe the importance of cellulose in them human diet.

  cellulose is a polymer if beta-glucose. it is important for dietary fibre!
• Write balanced equations for the complete oxidation of fructose, C6H12O6

  C6H12O6 + 6O2 → 6CO2 + 6H2O
• What is the difference between beta and alpha glucose

  the hydroxyl group on the far right
• a compound that contains less oxygen is more easily oxidized

  with less energy
• Describe the chemical composition of phospholipids and their function in the body, other than as energy storage.

  Chemical composition:glycerol AND «two» fatty acids AND «one» phosphate 

  Function:cell/plasma membrane 
• Describe how enzymes catalyse reactions in the body.


  by a substrate binding to an enzymes active site. They provide an alternative pathway with lower activation energy, speeding up rate of reaction
• some industrial uses of enzymes 


  Additives to detergents, breakdown of oil spills/industrial wastes, balking, etc.
• For non-competitive inhibition what happens to Vmax and Km? 


  for Vmax, it decreases due to denaturation of active site of the enzyme, decreasing the rate of reaction. Km remains the same due to no decrease in affinity of enzyme for substrate concentration.
• For competitive inhibition what happens to Vmax and Km? 


  Vmax does not change but Km is higher due to the fact that Vmax needs more substrate concentration to reach Vmax.
• State the three components of a monomer of DNA (a nucleotide).

  a phosphate group, nitrogenous base, and Deoxyribose
• Outline one structural similarity and one structural difference between hemoglobin and myoglobin.

  both contain a heme group or Fe2+. difference is that myoglobin has one polypeptide chain AND hemoglobin has four polypeptide chains OR myoglobin has no quaternary structure AND hemoglobin has quaternary structure
• A chiral carbon atom

  a carbon atom that is bonded to four different atoms or groups. With one exception, amino acids are chiral (glycine is not).
• CORN rule applied to naming steroisomers 


  If the Corn (COOH-R-NH3) is clockwise, it is a D-isomer. If the corn is counter clockwise it is a L-Isomer
• the proteins in our bodies are only composed of what?

  L-enantiomers of amino acids (L- configuration)
• what does the D and L convention refer to in stereochemistry of amino acids?

  the optical activity of the enantiomers of glyceraldehyde: D-glyceraldehyde is a dextororotary (right) and L-glyceraldehyde is levorotatory (left).
• unsaturated fats and oils contain carbon -->

  carbon to carbon double bonds
• unsaturated fats and oils exist in two forms

  cis-isomers and trans-isomers
• which is cis and which is trans (oleic acid and elaidic acid) 


  oleic acid is cis isomer and elaidic acid is trans isomer
• which fattu acids have higher melting points? Trans or cis? 


  trans have higher melting points because the molecules in trans - fatty acids are able to pack more closely together. (stronger intermolecular forces and thus higher melting points)