Digestion & Respiration
Lab 610/14/13
Digestion,Respiration
Photosynthesis, Respiration
Everything respires!!
• energy – the capacity to do work. All organisms need energy to live and do any activity beyond just living.
• digestion –breakdown of food into smaller units that can be absorbed by organism (i.e. glucose).
– hydrolysis: (-lysis: to separate) Decomposition of a chemical compound by reaction with water, such as the dissociation of a dissolved salt or the catalytic conversion of starch to simple sugars – digestion is hydrolytic
Digestion and respiration:
Digestion: more than food in your belly
• Chewing (mastication)
– Physical breaking-up of food
• Salivary amylase
– Enzyme that catalyzes production of simple sugars from starch in our mouths
• From there, down the pipe
• respiration – exchange of oxygen and carbon dioxide between organism and environment.
– Humans: breathing; inhaling (O2 in) and exhaling (CO2 out)
– Plants: gas exchange through stomata
• respiration – nutrients converted into useful energy
– Through a series of catabolic reactions, glucose (from digestion) is broken down and energy is released.
– In a series of anabolic reactions, the energy is used to synthesize adenosine triphosphate (ATP), the primary source of energy for organisms.
Catabolic = break down complex into simple
Anabolic = combine simple to form complex
Respiration – 2 DEFINITIONS! …or at least a 2 part definition…
Respiration – aerobic and anaerobic
Today’s Lab has 3 parts:
• Part A – Human Respiration• Part B – Bean Seed Respiration• Part C – Salivary Amylase Digestion of Starch
Set up Part C first.
Part A – Human Respiration
• Fill a test tube with water• Add 2 drops phenol red, swirl to mix
Red=basic yellow=acidic• Insert a straw and gently blow (don’t suck)
Predictions?think about the pH scale and this equation…
CO2 + H2O → H2CO3 → H+ + HCO3−
Part B – Bean Seed Respiration
• 3 types of seeds:1. Killed with formaldehyde2. Living but dormant, from seed packet3. Germinating
• Wear gloves when handling formaldehyde beans and DON’T breath in the fumes!!!
Which groups do you predict to be capable of respiration? Which should respire most?
Bean Set-up
• 4 test tubes – rinse with distilled water and dry1. Control (no seed)2. 1 killed seed (not 3)3. 1 dormant seed (not 3)4. 1 germinating seed (not 3)
• Place seeds on top of straw piece in test tube• Record color of solution at time 0, 15, 30 minutes
from start
Part C - Salivary Amylase Digestion of Starch
• In humans, the first digestive reaction of starch produces a disaccharide called maltose.
• catalyzed by amylase (an enzyme found in human saliva)
starch amylase maltose
Enzymes
• Catalyze (speed up) chemical reactions• Almost all reactions need enzymes• All are proteins – specific for certain reactions• Can be denatured (lose shape) at high
temperatures
Observing Digestion…
Starch + iodine = blue-black colorMaltose + iodine = no color change
As starch is digested into maltose the blue-black color will disappear.
Part C Set-up
• Before you start read thoroughly!!! This is easy to mess up!
• To give you a basis for test (in separate tubes)– 2 drops starch + 1 drop iodine– 2 drops maltose + 1 drop iodine
• Collect 5 beakers, 5 eyedroppers, 4 test tubes, rinse with distilled water, dry
Clean ALL Glassware
• Please wash and dry all glassware• Clean up area• Leave how you found it!
PART CREPEAT 3 TIMES @ 5 MINUTE INTERVALS – blue/black should disappear with time in beaker C
D - control“Saliva” A CB
Starch StarchStarchStarch
5 drops 5 drops 5 drops 5 drops
iodine iodine iodine iodine
+
+
+
+++
Quiz next time:
1. Definitions1. Respiration
1. Aerobic2. Anaerobic
2. Digestion3. Enzyme4. pH
2. Lab components1. What happened in part A? Why?2. What Happened in part B? Why?3. What happened in part C? Why?
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