Lab 5 – Diffusion, Osmosis and Enzymes. Lab 5 – Diffusion, Osmosis and Enzymes

Objective: The objective of this lab is to introduce you to the concepts of diffusion, osmosis and enzyme activity.

Reading Assignment: Read 4.9 and 5.4; Diffusion and Osmosis and How Enzymes Work from the textbook Essentials of the Living World.

 

For this lab you will need to supply the following materials:

Camera or cell phone (you will upload pictures of your experiment)

Kitchen scale (food scale, it can weigh in either ounces or grams)

Microwave

Liquid measuring cup

Teaspoon

Tablespoon (3 Tsp = 1 Tbs)

Several Drinking cups (1 needs to hold at least 2 cups of liquid)

1 Potato

Knife

Blender or Potato masher

Zip lock sandwich bag (not a freezer bag)

Pancake syrup

Salt

Sugar

Vinegar

Hydrogen Peroxide (H2O2)

 

Solutions to prepare

Sucrose solution – add one tablespoon of sugar to 1 cup of water

 

Exercise 1 – Diffusion

· In this exercise you will observe the diffusion of water through a semipermeable membrane (a plastic bag)

Step 1. Place ¼ of a cup of pancake syrup into a plastic zip lock bag and seal the bag.

Step 2. Weigh the bag using a small kitchen scale and record the weight on your worksheet.

Step 3. Fill larger cup (2 cup measuring or equivalent) with 1 cup of water. Record the time.

Step 4. Place the syrup bag in the larger cup and leave overnight (12+ hours).

Step 5. Remove the bag, dry it off and weigh it using a small kitchen scale. Record weight on your worksheet and the time you ended the experiment. (Hint: The bag should gain weight. If it loses weight you may have had a puncture. You must redo this exercise).

Step 6. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name and a photo ID.

Exercise 2 – Osmosis

· In this exercise you will determine the result of putting cells into solutions of various tonicity.

Step 1. Cut (2) potato slices: 3 inches long, 1 inch wide, 0.5 inches thick.

Step 2. Prepare two coffee cups with the following solutions:

Cup 1 = add one cup of water

Cup 2 = add one cup of water and 1 teaspoon of salt

Step 3. Add one potato slice to each cup and let stand for 1 hour.

Step 4. Remove potato slices and determine if the slice is crisp or limp. Record your observations of the slices on the data sheet.

Step 5. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name, and a photo ID.

Exercise 3 – Enzyme Activity

· In this exercise you will observe factors that affect the enzyme activity of catalase. Catalase is found in potato cells.

H2O2 (hydrogen peroxide) 2 H2O + O2 (oxygen gas) when catalase is present.

Step 1. Place the remaining amount of potato in a blender with two tablespoons of water. Blend to a paste. If you don’t have a blender use a potato masher to make the paste.

Experiment 3-1

Step 2. Transfer one tablespoon of the paste to a small cup and add 1 tablespoon of hydrogen peroxide.

Step 3. Mix together by gently rotating the cup clockwise and record your observations on the data sheet

Step 4. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name and photo/student ID.

 

Experiment 3-2

Step 5. Transfer one tablespoon of the paste to a small cup and add 1 tablespoon of sucrose solution.

Step 6. Mix together by gently rotating the cup clockwise and record your observations on the data sheet.

Step 7. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name and photo/student ID.

 

Experiment 3-3

Step 8. Transfer one tablespoon of the paste to a small cup and add 1 tablespoon of vinegar (an acid).

Step 9. Next add 1 tablespoon of hydrogen peroxide.

Step 10. Mix together by gently rotating the cup clockwise and record your observations on the data sheet.

Step 11. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name and photo/student ID.

 

Experiment 3-4

Step 12. Transfer one tablespoon of the paste to a small cup and add 1 tablespoon of water.

Step 13. Microwave on high for 1 minute.

Step 14. Remove from microwave (careful it’s hot) and allow 5 minutes to cool.

Step 15. Next add 1 tablespoon of hydrogen peroxide.

Step 16. Mix together by gently rotating the cup clockwise and record your observations on the data sheet.

Step 17. Take a picture of the completed exercise and upload to the worksheet. Make sure it includes the date, your name and photo/student ID.

Lab 5 – Diffusion, Osmosis and Enzymes

 

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Lab 11: Frog & Fetal Pig Dissections. Virtual Lab: Virtual Frog Dissection

http://mhhe.com/biosci/genbio/virtual_labs/BL_16/BL_16.html

1. If you come upon any terms that are unfamiliar to you, please refer to your textbook for further explanation or search the word here: http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx

2. In this exercise, you will be performing a virtual frog dissection. To begin, click on the “Introduction” link on the opening page. Read through and listen to the information presented to learn about the basics of dissection and animal phylogeny. When you are finished, click the “Menu” button at the bottom of the page to return to the opening page of the laboratory activity.

3. Once you are back to the opening page, click the “External Anatomy” button. Read through, watch and listen to the information presented in these segments. When you are finished, click the “Menu” button at the bottom of the page to return to the opening page of the laboratory activity.

4. The last portion of this activity involves an examination of the internal anatomy of a frog. To do this, click the “Internal Anatomy” button on the opening page of the laboratory. Read through, watch and listen to all of the information presented in these segments and actively participate where required. You may have to do a virtual cut on the frog by dragging the appropriate tool to the frog or label organs of the dissected frog by dragging the appropriate organ names to the site on the opened frog. Please STOP when you are through with each labeling step and be sure to fill in your final answers on Figures 1 and 2 below.

 

Figure 1: Digestive System Organs

A   =

B   =

C   =

D   =

E   =

F   =

 

Figure 2: Organs   of the Circulatory, Respiratory, Excretory and Reproductive Systems

A   =

B   =

C   =

D   =

E   =

F   =

G =

H =

Frog Dissection Post-laboratory Questions:

1.  The dorsal side of the leopard frog:

a.  Is a light, solid color

b. Is a colored and patterned

c. Is initially cut during a dissection

d. A and C

2.  Leopard frogs:

a.  Are invertebrates

b. Are warm-blooded

c. Have a gills at one time during their life cycle

d. All of the above

3. In regards to the external anatomy of a leopard frog:

a.  It is easy to tell the sex of the animal

b. The cloaca is at the anterior end of the animal

c. The feet of the hind limbs have 5 toes

d. All of the above

4.  In the opened mouth of the leopard frog, one can see:

a.  The nostrils

b. The glottis

c. The vomerine teeth

d. A and B

e. All of the above

5.  Which of the following is found in the digestive system of the leopard frog but not in that of a human?

a.  Gall bladder

b. Stomach

c. Pancreas

d. Liver

e. None of the above

6.  Arteries in the circulatory system:

a.  Carry blood to the heart

b. Carry blood away from the heart

c. Carry out diffusion of gases

7.  In the leopard frog heart:

a.  The right atrium carries oxygen rich blood

b. The left atrium carries oxygen poor blood

c. There are 3 chambers present

d. All of the above

8.  By comparison to the leopard frog heart, the human heart:

a.  Has 4 chambers present

b. Carries mixed blood in the ventricles

c. Is more efficient

d. A and C

e. All of the above

9.  Fat bodies play a role in:

a.  Respiration

b. Circulation

c. Hibernation

d. Reproduction

e. C and D

10.  The most anterior portion of the leopard frog brain is/are the:

a.  Olfactory lobes

b. Cerebrum

c. Optic lobes

Virtual Lab: Virtual Fetal Pig Dissection

https://www.whitman.edu/academics/departments-and-programs/biology/virtual-pig

Figure 1: Fetal Pig – Digestive System

 

1. __________________________
2. __________________________
3. _________________________
4. _________________________
5. ________________________
6. _________________________
7. __________________________
8. __________________________
9. __________________________
10. _________________________
11. _________________________
12. _________________________
13. ________________________

Identify the organ (or structure)

14. _____________________________ Opening (valve) between stomach and small intestine.
15. _____________________________ Stores bile, lies underneath the liver.
16. _____________________________ A branch of the large intestine, a dead end.
17. _____________________________ Separates the thoracic and abdominal cavity
18. _____________________________ Membrane that holds the coils of the small intestine.
19. _____________________________ The straight part of the small intestine, after stomach.
20. _____________________________ Empties bile into the duodenum from the gall bladder.
21. _____________________________ The last stretch of large intestine
22. _____________________________ Bumpy structure under the stomach; makes insulin
23. _____________________________ Lies between the two umbilical vessels.

Figure 2: Urinary and Reproductive Systems

Male  Female

Identify the Organs (or structure) on the above diagram:

A.

B.

C.

D.

E.

F.

G.

H.

I.

J.

K.

Identify the organ:

· Urine passes through the _________ to reach the urinary ___________ for storage.

· Urine exits the ________ to the outside through the ____________

· The ______________ is where sperm production takes place.

· The ______________ contain all the developing eggs the female pig will ever have.

· Called a ___________________ in humans, the __________ receives the egg from the ovary at ovulation.

· Fertilized eggs travel from the oviducts into the ______________ for implantation.

Lab 11: Frog & Fetal Pig Dissections

 

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