1. Digestion & Respiration
Lab 6
10/14/13

2. Photosynthesis, Respiration
Everything respires!!
Digestion,
Respiration

3. Digestion and respiration:
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

4. 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

5. Respiration – 2 DEFINITIONS! …or at least a 2 part definition…
 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

6. Respiration – aerobic and anaerobic

7. 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.

8. 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−

9. Part B – Bean Seed Respiration
3 types of seeds:
Killed with formaldehyde
Living but dormant, from seed packet
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?

10. Bean Set-up 4 test tubes – rinse with distilled water and dry
Control (no seed)
1 killed seed (not 3)
1 dormant seed (not 3)
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

11. 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

12. 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

13. Observing Digestion…
Starch + iodine = blue-black color Maltose + iodine = no color change As starch is digested into maltose the blue-black color will disappear.

14. 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

15. Clean ALL Glassware Please wash and dry all glassware Clean up area
Leave how you found it!

16. A B C D - control PART C “Saliva” Starch Starch Starch Starch + + + +
REPEAT 3 5 MINUTE INTERVALS – blue/black should disappear with time in beaker C A B C
“Saliva”
D - control + + + + + +
Starch
Starch
Starch
Starch
5 drops
5 drops
5 drops
5 drops
iodine
iodine
iodine
iodine

17. Quiz next time:
Definitions
Respiration
Aerobic
Anaerobic
Digestion
Enzyme pH
Lab components
What happened in part A? Why?
What Happened in part B? Why?
What happened in part C? Why?