need to write lab report

in the we had already done lab and result is also ready. all the result and requirement will provided base on that picture you need to write lab report.

Here is the example of lab report format. Biology 1406 Lab Report 2: Selective Permeability of Membranes

Name: Student X

Lab Instructor: Name of Lab Instructor X Introduction This lab exercise is intended to study selective movement of substances through selective permeable membranes. Osmosis occurs when water passes through a semi-permeable layer from a high to low concentration gradient to reach equilibrium. Diffusion, on the other hand, allows the movement of molecules from high concentration to low concentration.

Hypothesis: If molecules are too large then they won’t be able to move across the selectively permeable membrane.

Materials and Methods

In this experiment, selectively permeable dialysis tubing is used to demonstrate movement of substances through cellular membranes. The dialysis tubing allows passage of some molecules and obstructs others.

The following materials were used to conduct the experiment:

 1 25-cm length of dialysis tubing, soaking in dH2O

 Two 10-cm pieces of string

 Bottle of 1% soluble starch in 1% sodium sulfate

 Dishpan half-filled with dH2O

 400-mL graduated beaker

 Ring stand and funnel apparatus

 Bottle of 1% albumin in 1 % sodium chloride

 8 test tubes

 Test tube rack

 China marker

 Iodine solution in dropper bottle

 2%barium chloride reagent in dropper bottle

 2% silver nitrate reagent in dropper bottle

 Biuret reagent in dropper bottle

 Scissors

 25ml Beaker

 Disposable pipettes


Pictures/drawings of the Setup (If required by instructor)


1. Soak the 15cm dialysis tubing in dH2O

2. Obtain a section of the dialysis tubing that has been soaked in dH2O

3. Fold over and tie the end of the tubing with string to form a leak-proof bag.

4. Slip the other end of the bag over the stem of a funnel.

5. Fill the bag with 10ml of the solution of 1% soluble starch in 1% sodium sulfate.

6. Remove the bag, fold over and tie the open end.

7. Rinse the tied bag in a dishpan filled with dH2O

8. Pour 200 ml of a solution of 1% albumin in 1% sodium chloride into the beaker

9. Put the bag into the beaker.

10. Label 8 test tubes 1-8.

11. After 60 minutes, dispense 5 ml of the beaker’s contents into test tubes (1-4).

12. Rinse the dialysis bag in the dishpan of dH2O. Cut the bag with scissors and pour

the contents into a 25mL-beaker cylinder. Pipette 5-ml into each of the remaining

4 test tubes (5-8).

13. Perform tests below for starch, sulfate ions, chloride ions, and protein in test

tubes 1-4. Record results in Table 1. Repeat tests below for test tubes 5-8.

Record results in Table 2. (The results tabulated as shown in the table below.)

Test for Starch add 3-5 drops of iodine solution to test tube 1 & 5. A blue/black color

change indicates the presence of starch.

Test for Sulfate ion add 3-5 drops of 2% barium chloride to test tube 2 & 6. A white

precipitate of barium sulfate indicates the presence of sulfate ions.

Test for Chloride ion add 3-5 drops of 2% silver nitrate to test tube 3 & 7. A milkywhite

precipitate of silver chloride indicates the presence of chlorine ions.


Test for Protein add 3-5 drops of biuret reagent to test tube 4 & 8. A change in color

from blue to violet indicates the presence of protein.


The contents of the beaker after 25 minutes tested positive for sulfate ions. The

contents of the beaker tested negative for starch (Table 1). The contents of the dialysis

bag after 25 minutes tested positive for chloride ions. The contents of the bag tested

negative for albumin (Table 2).

Table 1: Test Results for Substances in Beaker


Start of Experiment

After 25 minutes

Starch – –

Sulfate ion – +

Chloride ion + +

Albumin + +

Contents of Beaker: (+) = presence, (-) = absence

Table 2: Test Results for Substances in Dialysis Bag


Start of Experiment

After 25 minutes

Starch + +

Sulfate ion + +

Chloride ion – +

Albumin – –

Contents of Dialysis: (+) = presence, (-) = absence

Figure 1. Results of tests on beaker solution Figure 2. Results of tests on bag solution

(Test tubes 1-4). (Test tubes 5-8).



According to the results, the hypothesis can be supported. The experiment

demonstrated that the selectively permeable pores on the dialysis tubing are very small

and do not allow large molecules such as starch and albumin to pass through. The

pores allow the smaller ions such as sulfate and chloride ions to pass through the

selectively permeable membrane.

(If experiment results do not accurately support your hypothesis, then list any potential

source of error that could have occurred. For example, the bag was not left in the

beaker solution for the correct amount of time.)


Any source material used should be cited appropriately. See example below.

Mazan MR, Hoffman AM. 2001. Effects of aerosolized albuterol on physiologic

responses to exercise in standardbreds. Am J Vet Res. 62(11):1812–1817.


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