exercise 39a/39 chemical processes of digestion bio132 …€¦ · chemical bonds resulting in...
TRANSCRIPT
Digestion = hydrolysis reactions involving enzymes
(enzymes = biological catalysts)
-a specific enzyme acts on a specific substrate using water to break
chemical bonds resulting in particular products
-the specificity is based on the active site of the enzyme; a space in
folded protein structure where the substrate will fit and bind
-enzymes are usually named for their substrate and end in “-ase”
BIO132 Lab 7:
Exercise 39A/39 Chemical Processes of Digestion
Cofactor
Figure 39A.1 / 39.1
Lipid emulsification by bile
(mix)
Fats and oils + bile --------------------------> emulsified fats
(tiny droplets suspended in water)
allows easier access by water-soluble enzymes
*NOT digestion!
Figure 39A.1 / 39.1
Enzymes are biological catalysts, proteins that function to “speed up”
chemical reactions by holding substrate in the active site.
Enzymatic reactions can be impacted by environmental conditions:
-Enzymes have optimal temperatures and pH for their activity.
-Human digestive enzymes have an optimal temperature equal to body
temperature (37°C). Most have an optimal pH around neutral (pH7)
-If the temperature is too high, or pH is too acidic or basic, enzymes can
be denatured and will no longer catalyze the reaction.
-If the temperature is too low, enzymes will function slowly or not at all
in the reaction.
native conformation denatured
Salivary Amylase Digestion of Starch
Tube no.
Additives (3 gtt ea)
1A 2A 3A 4A
Boil amylase 4 min, then add starch
5A 6A
0°C 37°C 37°C 37°C 37°C 37°C Incubation condition
IKI test (color change)
Positive (+) or negative (-) result
Benedict’s test (color change)
Positive (+) or negative (-) result
Additive key:
= Amylase = Starch = Maltose = Water
Add acid
Amy Warenda Czura, Ph.D. 1 SCCC BIO132 Lab 7 Digestion
Salivary Amylase Digestion of Starch
Tube no.
Additives (3 gtt ea)
1A 2A 3A 4A
Boil amylase 4 min, then add starch
5A 6A
0°C 37°C 37°C 37°C 37°C 37°C Incubation condition
IKI test (color change)
Positive (+) or negative (-) result
Benedict’s test (color change)
Positive (+) or negative (-) result
Additive key:
= Amylase = Starch = Maltose = Water
black
+
-
blue
yellow
-
-
blue
yellow
-
+
orange
black
+
-
blue
yellow
-
+
orange
dark
partial +
yellowish
partial +
Add acid
Unnumbered Figure 39.3
Pancreatic Lipase Digestion of Fats
Tube no.
37°C
Positive (+) or negative (-) result
Additive key:
= Lipase
1L
Boil lipase 4 min, then add litmus cream.
2L 3L 4L 5L 4B 5B
37°C 37°C 37°C 37°C 0°C 0°C
Color change
Incubation condition
Additives (5 gtt ea)
= Litmus cream = Water = Pinch bile salts
15
Pancreatic Lipase Digestion of Fats
Tube no.
37°C
Positive (+) or negative (-) result
Additive key:
= Lipase
1L
Boil lipase 4 min, then add litmus cream.
2L 3L 4L 5L 4B 5B
37°C 37°C 37°C 37°C 0°C 0°C
Color change
Incubation condition
Additives (5 gtt ea)
= Litmus cream = Water = Pinch bile salts
15
bluish
purple bluish purple pink
- ++ - -
purple bright
pink
pinkish
purple
+++ + -/+
bluish
purple
Amy Warenda Czura, Ph.D. 2 SCCC BIO132 Lab 7 Digestion