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?