LAB 5 – MEMBRANE TRANSPORTLAST NAME 1

Student Name

Date

Mr. Martin

Honor’s Biology - Period

TITLE

Lab 5 – Membrane Transport

The effect of various sucrose (sugar) concentrations on the percent mass change of a Russet potato (Solanumtuberosum) as investigation of osmosis.

INTRODUCTION

This section should be written using active voice and NO personal pronouns. For example, DO NOT SAY “I/we studied the effect…” but rather “The effect that was studied…”. Write this intro by stating what was done in this experiment. Use the bullets below as guidelines but write using complete sentences.

  • identify the phenomenon that was studied, explain what was done in this experiment
  • include relevant background information
  • use or define relevant key terms (see lab handout)
  • include a diagram of cells in different solutions (hypertonic, hypotonic & isotonic)
  • include a figure showing tonicity, see example
  • hypothesis – if a cell is in ____ concentration the percent mass will ______(increase / descrease)

Figure 1 Types of solution (

Table 1 – Variables

Variable
Independent Variable
  • control group

  • experimental groups

Dependent Variable
Controlled Variables

MATERIALS AND METHODS

  • list the materials that were used
  • insert a drawing/sketch/picture of your experimental set up (see figure 2 at right)

Figure 2 Diagram of experimental set up (Martin, 2016)

  • describe the steps that were performed in a bulleted or numbered list

RESULTS

  • create or insert a data table of YOUR GROUP DATA (it should look some like the sample below)

Table 2: Group Data / Initial Mass (grams) / Final Mass (grams) / Percent Change in Mass (%)
0.0 M sucrose
(CUP 1)
0.2 M sucrose
(CUP 2)
0.4 M sucrose
(CUP 3)
0.6 M sucrose
(CUP 4)

SHOW THE FORMULA YOU USED FOR CALCULATING PERCENT CHANGE IN MASS

  • Identify and discuss the formula used to calculate the percent change in mass.
  • create or insert a data table of the CLASS AVERAGE (MEAN) DATA (it should look some like the sample below)
  • The table below is the data that will be graph, a scatter plot

Table 3: Mean Class Data / Percent Change in Mass (%)
0.0 M sucrose
(CUP 1)
0.2 M sucrose
(CUP 2)
0.4 M sucrose
(CUP 3)
0.6 M sucrose
(CUP 4)
  • You must include AT least ONE photograph of your results (i.e. the cups, a potato being massed) no faces should be in the picture
  • create and insert graph of the class average (mean) data
  • include:

LAB 5 – MEMBRANE TRANSPORTLAST NAME 1

  • graph title – given to you
  • axis title – you need to add
  • units
  • line of best fit – given to you

LAB 5 – MEMBRANE TRANSPORTLAST NAME 1

  • See example below
  • To access the data from the graph below, right click on the graph and click “Edit data”. This will open an excel spread sheet that you can edit an add your data. The graph will be updated

Figure 3: Average percent mass change for potatoes in various sucrose concentrations

  • identify the point on the graph where the line of best fit crosses the “0% change line”.
  • this is the point where the potato and the solution are isotonic, state what the concentration of sucrose is at that point.

DISCUSSION

answer the discussion below.

  1. what do the data show for this lab? Explain the numbers that your group calculated.
  2. Why did you calculate the percent change in mass rather than simply use the change in mass?
  3. The cell membrane is semipermeable or selectively permeable. What does that term mean? What are some molecules that are permeable to membrane?
  4. If there is a net decrease in the mass of the potatoes, what substance is moving out of the potato cells?
  5. In which sucrose solution, 0.6 M or 0.2 M is the concentration of water molecules higher?
  6. From your graph, what concentration of sucrose gave (or would give) no change in mass of the potato cubes? If your graph does not show this, estimate a value. You can give a range if necessary. What is the term for this?
  7. What term is used to describe the solution outside of the cell in relation to the cell contents when:

a)water moves into the potato cells? Which concentrations showed this happen?

b)water moves out of the potato cells? Which concentration showed this happen?

REFERENCES

MUST BE APA format

  • include sites for any background information (copy and paste the web address)

From a website:

Last, F. M. (Year, Month Date Published). Article title. Retrieved from URL

Citing an image taken from the web:

Figure 3.Experimental Setup (Martin, 2016).

Reference

Martin, J. (2016). Lab Membrane Transport. Retrievedfrom

THOUGHTS and GUIDE LINES:

  • the entire document should be written in the same font and same size
  • Acceptable sizes are 11 or 12 size. (Data tables with large amounts of numbers can be formatted with smaller size fonts to accommodate the numbers.
  • Use a “normal font” – recommended fonts are Calibri, Times New Roman, & Courier New.
  • Avoid the use of personal pronouns, (Do not use: I, me, we, my or our etc.)
  • Once you have finished the report review the document check for:
  • All the same size font
  • Headings are uniform (same style, indentation, punctuation…)
  • Spacing is uniform between text (there should not be large gaps between sections. Be consistent with formatting
  • Data tables should not wrap between two pages. If a table does not fit at the bottom of a page, move it to the next page by pushing the “Enter or Return” key.
  • Always proof read your paper. It is a good practice to proof read a classmate’s paper and have them proof read yours.
  • Lab Reports will need to be turned in at the beginning of class before the tardy bell rings. You have to have a hard copy (printed out)
  • Save all old lab reports electronically, you should maintain a class folder (USB flash drive or in the cloud like Google drive)