Lab 3: Cell Structure and Function

INSTRUCTIONS:

· To conduct your laboratory exercises, use the links to the instructions for each lab, found in the “Course Content” section of the classroom.

· On your own and without assistance, complete this Lab 3 Answer Form electronically and submit it via the Assignments Folder by the date listed on your Course Schedule (under Syllabus).

· Type your answers into the gray shaded boxes provided after the questions and in the tables. The boxes will expand as you type.

· When necessary, insert graphs prepared in Excel, or image files (scans, photos, etc.) into the clear boxes provided.

· Save your Lab 3 Answer Form in the following format: LastName – Bio 102 Lab – Lab 3 Answer Form (e.g., Largen – Bio 102 Lab – Lab 3 Answer Form).

· You should submit your document in a Word (.doc or .docx) or Rich Text Format (.rtf) for best compatibility.

· Please note that this answer form also serves as a grading rubric. The grading information for each question is provided in red text in parentheses following each question/graph/table, etc. Skipping a requested question, part of a question, table, graph, etc., will result in the designated amount of percentage points being deducted from the grade for this lab answer form.

Experiment 1: Cell Structure and Function (25 points)

1. Diagram Labelling: Identify each of the labeled structures in the following slide image of an onion root tip (1000X):

(2 point for each = 8 points)

A
B
C
D

2. What is the difference between the rough and smooth endoplasmic reticulum? (2 points)

3. (a) Would an animal cell be able to survive without mitochondria? (1.5 points) (b) Why or why not? (3.5 points)

a
b

4. What could you determine about a specimen if you observed a slide image showing the specimen with a cell wall, but no nucleus or mitochondria? (5 points)

5. Hypothesize why parts of a plant, such as the leaves, are green, but other parts, such as the roots, are not. Use scientific reasoning to support your hypothesis. (5 points)

Experiment 2: Osmosis – Direction and Concentration Gradients (75 points)

Data Tables and Post-Lab Assessment

Table 3: Sucrose Concentration vs. Tubing Permeability

(each cell is worth 1.5 points = 30 points for the table)

Band Color	% Sucrose in Beaker	% Sucrose in Bag	Initial Volume (mL)	Final Volume (mL)	Net Displacement (mL)
Yellow
Red
Blue
Green

Take a picture of your results. Include a note with your name and date on an index card in the picture. Insert picture here (3 points):

Hypothesis: (2 points)

Post-Lab Questions

1. For each of the tubing pieces, identify whether the solution inside was hypotonic, hypertonic, or isotonic in comparison to the beaker solution in which it was placed, by completing the following table: (2.5 points per cell = 10 points)

Solution in tubing with ____ band color….	…was hypertonic, hypotonic, or isotonic (select one)…	…in comparison to…
Yellow		…beaker solution in which it was placed.
Red
Blue
Green

2. (a) Which tubing increased the most in volume? (1.5 points) (b) Explain why this happened. (3.5 points)

a
b

3. What do the results of this experiment this tell you about the relative tonicity between the contents of the tubing and the solution in the beaker? (5 points)

4. What would happen if the tubing with the yellow band was placed in a beaker of distilled water? (5 points)

5. How are excess salts that accumulate in cells transferred to the blood stream so they can be removed from the body? Be sure to explain how this process works in terms of tonicity. (5 points)

6. If you wanted water to flow out of a tubing piece filled with a 50% solution, what would the minimum concentration of the beaker solution need to be? Explain your answer using scientific evidence. (5 points)

7. (a) How is this experiment similar to the way a cell membrane works in the body? (2.5 points) (b) How is it different? (2.5 points) Be specific with your response.

a
b