Osmosis week 3 experiment answer sheet

Please submit to the Week 3 Experiment dropbox no later than Sunday midnight.

SUMMARY OF ACTIVITIES FOR WEEK 1 EXPERIMENT ASSIGNMENT

 

·         Experiment 3 Exercise 1 – Diffusion: Movement of Solutes across a Membrane

·         Experiment 3 Exercise 2 – Osmosis: Movement of Water across a Membrane

 

Experiment 3 Exercise 1: Diffusion – Movement of Solutes across a Membrane

 We will be using dialysis tubing to simulate a semipermeable membrane. This tubing allows small molecules (e.g., water, ions, glucose) to pass while preventing large molecules (e.g., macromolecules like proteins, starch, glycogen) from moving across.  Be sure you have read over the suggested material before starting this exercise and that you have reviewed the following animations:

Experimental Design

 

A.      The dialysis bag we will use is permeable to water and small molecules (e.g., less than 500 g/mol) and impermeable to large molecules (e.g., more than 500 g/mol).

B.      The dialysis bag is filled with a mixture of glucose (molecular weight = 180 g/mol) and protein (molecular weight = 10,000 g/mol) dissolved in water. A small subsample of the dialysis bag contents is saved and will be used in Step 4.

C.      The dialysis bag is then placed into a beaker of water. A small subsample of beaker water is also saved and is to be used in Step 4 as well.

The presence or absence of glucose and protein will be determined using indicators. Indicators change colors in the presence certain materials. The two tests that we’ll use are the Benedict’s test for simple sugars (e.g., glucose) and theBiuret test for the presence of proteins.

·         If glucose is present, the Benedict’s indicator will turn green. If no glucose is present, the solution will be blue.

·         If protein is present, the Biuret indicator will turn violet.  If the solution remains clear, then no protein is present.

4.    The subsample of dialysis bag solution and the beaker water are tested for the presence of glucose and protein. SeeTable 1 below for the results.

5.    The dialysis bag is then left in the beaker of water for 60 minutes.

6.    At the end of 60 minutes, the dialysis bag solution and the beaker water are again tested for the presence of glucose and protein. See Table 1 below for the results.

 

Table 1. Results of testing of the dialysis bag and beaker contents at the beginning and end of the Experiment.

 

Questions

1.    Summarize the results regarding the presence (+) or absence (-) of glucose and protein in the dialysis bag and beaker in Table 2 below (4 pts):

 

  

2.    Explain the movement or lack of movement of protein and glucose across the dialysis bag membrane (4 pts)

3.    Which solution, that in the bag or that in the beaker, is hypotonic compared with the protein solution (2 pts)?

4.    What factors affect the movement of molecules across a semipermeable membrane? Which factor plays the greatest role in biological systems (4 pts)?

 

5.    Briefly explain what active transport is and how it differs from passive transport, especially in terms of concentration gradients (4 pts).

 

 

 

Experiment 3 Exercise 2: Osmosis – The Movement of Water across a Membrane

 

Before starting, let’s see what you know about the terms hypotonic, isotonic and hypertonic. Examine the diagrams below. Note that the small green circles represent dissolved solutes like salt, glucose, and amino acids. You can assume that the additional space surrounding the solutes is water and that the tan area is INSIDE the cell.

 

Question

 

1.      Define each term below in terms of solute concentration outside compared to the inside of the cell. You do not need to explain which direction water will move (3 pts).

a.      Hypotonic –

             b.      Isotonic – 
              c.       Hypertonic –

 

Procedure

1.    Open the following website to get started:

The Biology Place. No Date. Osmosis: Movement of Water across Membranes
http://www.phschool.com/science/biology_place/biocoach/biomembrane1/osmosis.html

B.      Read over the information presented and then Click on 

C.      Then, Click on .  Read through the information presented and be sure to click on Animate beneath the illustration.

2.      What concentration of salt is isotonic to animal cells (1 pts)? 

 

3.      When cells are in isotonic solution, is there movement of water into or out of the cell?  If so, describe this movement (3 pts).  

 

  1. Click on  .

    E.      Read through the information presented and be sure to click on Animate beneath the illustration. When ready, answer the following question.

 

 

4.      Describe the net movement of water molecules when cells are placed in a hypotonic solution.  Explain why water moves this way (3 pts).

 Procedure (continued)

G.     Read through the information presented and be sure to click on Animate beneath each of the illustrations. Answer the following questions. Your answers should incorporate the terminology used in the animations.

5.      What happens to an animal cell when placed in a hypotonic solution (2 pts)?

 

 

6.      What happens to plant cells when placed in a hypotonic solution? What accounts for the difference in outcomes between animal cells and plant cells (3 pts)?

 

 

Procedure (continued)

8.    Click on  

I.     Then,  Read through the information presented and be sure to click on Animate beneath the illustration. Answer the following question.

 

7.      Describe the net movement of water molecules when cells are placed in a hypertonic solution.  Explain why water moves this way (3 pts).

 

Procedure (continued)

10.  Click on  

K.      Read through the information presented and be sure to click on Animate beneath the illustration. Answer the following questions.

8.    Compare and contrast what happens to plant and animal cells when placed in a hypertonic solution. Be sure to use proper terminology (4 pts).

9.    Based on what you learned in this exercise, explain why salt might make a good weed killer (3 pts).

 

Week 3 Experiment Grading Rubric

 

 







Calculate Your Essay Price
(550 words)

Approximate price: $22

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more

Order your essay today and save 10% with the coupon code: best10