1. Aim: In what ways are enzymes specific ?
Do now:
List the ways enzymes are specific
So far you know that the shape of an enzymes is specific to the shape of the substrate.
When the enzymes fits the combined unit is call the “substrate-enzyme complex”
There is another criteria for enzyme action – temperature and pH

2. Enzymes work best under optimum conditions of temperature
Many work best at temperatures close to body temperatures and most lose their ability to catalyze if they are heated above 60 or 70o C.
The reason why enzymes are so sensitive to changes in pH and temperature is that such change can affect the interactions that hold the parts of the protein chain in place.

3. Enzymes work best under optimum conditions of pH
Many enzymes work best at a particular pH and stop working if the pH becomes too acidic or alkaline.

4. Enzyme changes shape and no longer fits the enzyme substrate complex
Extreme conditions of temperature and pH cause the enzyme to become denatured
Enzyme changes shape and no longer fits the enzyme substrate complex
If the shape of the active site is changed, the substrate molecule will no longer be able to form temporary attractions with the protein chain, because the chemical groups needed to do this will no longer be in the right place. We say that the enzyme has become denatured.

5. Optimum pH Graph pH 7 1.5 Rate 6.0-6.5 7-8 5.5 - 7 7 14 pH
Section 38-2
Graph
Site
Mouth
Stomach
Small intestine (from pancreas)
Duodenum
Ileum
Large Intestine pH 7
1.5
7-8
Rate
Create graphs showing conditions of pH. 7 14 pH

6. Cytochrome c is an enzyme that functions in respiration
Section 9-1
Mitochondrion
Electrons carried in NADH
Electrons carried in NADH and FADH2
Pyruvic acid
Glucose
Electron Transport Chain
Krebs Cycle
Glycolysis
Write the chemical equation for aerobic respiration
Glucose + oxygen  carbon dioxide + water
Mitochondrion
Cytoplasm
Go to Section:

7. Fermentation (without oxygen)
Chemical Pathways
Section 9-1
Glucose
Krebs cycle
Electron transport
Glycolysis
Chemical pathway depends on the evolution of the organism, many bacteria, yeasts are anaerobic
Higher organisms are aerobic
Alcohol or lactic acid
Fermentation (without oxygen)
Cytochrome c shuttles H+ to oxygen to produce water during aerobic respiration
Go to Section:

8. Electron transport chain with cytochrome c
Where else would cytochrome c function?

9. Anaerobic respiration
This reaction produces 2 ATP’s of energy. Found in yeast and simple organisms. Simple reaction does not go through the Krebs cycle or the electron transport chain. There is also no molecular oxygen to receive the hydrogens to form water.