Quiz: Qct 2, lab 1, 2, 4

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Quiz Qct 2, lab 1, 2, 4
Lab test Oct 10, lab 1, 2 and 4
Lab report Diffusion and Osmosis---lab 3 in the
lab manual
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Lab 4----Enzyme Analysis
Enzyme catalytic proteins, catalyze specific
reactions
Protein sucrase RNA ribozyme Ribonucleoprotein
proteinRNA
enzymes
enzyme
substrate
product
sucrase
Sucrose H2O
Glucose fructose
(hydrolysis)
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Active sites/binding sites enzyme and substrate
contact each other
Four levels of functional shape of a protein

• Primary structure amino acid sequence
• Secondary structure a-helix and ß-sheet when aa
  are attracted to each other (H-bond)
• Tertiary structure three dimensional structure
  when R groups interact with each other
  (hydrophobic interaction, S-S bond)
• Quaternary structure two or more polypeptide
  chains

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Enzyme activity
Conformation/structure/shape
factors
Factors
1. Temperature low T---- inhibit a reaction
high T---- speed up a reaction
Too high----denature enzyme (2nd, 3rd and 4th
structure will be affected)
2. pH low pH----more H
Affect 2nd, 3rd and 4th structure
High pH----more OH-
does not affect enzyme structure
3. Substrate concentration
Within a range, more substrate----speed up a
reaction untill the enzyme is saturated, more
substrate----no effect on the reaction rate