I need help with this lab due to unexpected emergancy;Attachment Preview;Lab_3_Answer_Sheet.doc Download Attachment;Your Full Name;UMUC Biology 102/103;Lab 3: Cell Structure and Function;INSTRUCTIONS;On your own and without assistance, complete this Lab 3 Answer Sheet;electronically and submit it via the Assignments Folder by the date listed in the Course;Schedule (under Syllabus).;To conduct your laboratory exercises, use the Laboratory Manual located under;Course Content. Read the introduction and the directions for each exercise/experiment;carefully before completing the exercises/experiments and answering the questions.;Save your Lab 3 Answer Sheet in the following format: LastName_Lab3 (e.g.;Smith_Lab3).;You should submit your document as a Word (.doc or.docx) or Rich Text Format;(.rtf) file for best compatibility.;Pre-Lab Questions;1. Identify three major similarities and differences between prokaryotic and;eukaryotic cells.;2. Where is the DNA housed in a prokaryotic cell? Where is it housed in a;eukaryotic cell?;3. Identify three structures which provide support and protection in a eukaryotic;cell.;Experiment 1: Cell Structure and Function;The structure of a cell dictates the majority of its function. You will view a selection of;slides that exhibit unique structures that contribute to tissues function.;Materials;Onion (allium) Root Digital Slide Images;Procedure;1. Examine the onion root tip digital slide images on the following pages. Then;respond to the Post-Lab Questions.;Onion Root Tip: 100X;Onion Root Tip: 1000X;Onion Root Tip: 1000X;Onion Root Tip: 100X. Each dark circle indicates a different nucleus.;Onion Root Tip: 1000X;Post-Lab Questions;1. Label each of the arrows in the following slide image: A=Chromosomes;B=Nucleus, C=Cytoplasm, D=Cell Wall;2. What is the difference between the rough and smooth endoplasmic reticulum?;3. Would an animal cell be able to survive without a mitochondria? Why or why not?;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. 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.;Experiment 2: Osmosis - Direction and Concentration Gradients;In this experiment, we will investigate the effect of solute concentration on osmosis. A;semi-permeable membrane (dialysis tubing) and sucrose will create an osmotic;environment similar to that of a cell. This selective permeability allows us to examine the;net movement of water across the membrane. You will begin the experiment with a 30%;sucrose solution, and perform a set of serial dilutions to create lower concentration;solutions. Some of the sucrose concentrations will be membrane permeable, while;others will not be permeable (can you determine why this is?).;Materials;(3) 250 mL Beakers;*Stopwatch;(1) 10 mL Graduated Cylinder;*Water;(1) 100 mL Graduated Cylinder *(4) 15 cm. Pieces of Dialysis Tubing;Permanent Marker;*Contains latex. Please handle wearing;*8 Rubber Bands (2 blue, 2 green,safety gloves if you have a latex allergy.;2 red, and 2 yellow);60 g Sucrose (Sugar) Powder;C12H22O11;*You Must Provide;4 Waste Beakers (any volume);*Paper Towels;*Be sure to measure and cut only the;*Scissors;length you need for this experiment.;Reserve the remainder for later;experiments.;Procedure;1. Use the permanent marker to label the three 250 mL beakers as 1, 2, and 3.;2. Cut four strips of dialysis tubing, each 15.0 cm long. Fill Beaker 3 with 100 mL of;water and submerge the four pieces of dialysis tubing in the water for at least 10;minutes.;3. After 10 minutes, remove one piece of tubing from the beaker. Use your thumb;and pointer finger to rub the tubing between your fingers, this will open the;tubing. Close one end of the tubing by folding over 3.0 cm of one end (this will;become the bottom). Fold it again and secure with a yellow rubber band (use;4. Tie a knot in the remaining dialysis tubing just above or just below the rubber;band. This will create a seal and ensures that solution will not leak out of the tube;later in the experiment.;5. To test that no solution can leak out, add a few drops of water to the tubing and;look for water leakage. If any water leaks, tighten the rubber band and/or the knot;in the tubing. Make sure you pour the water out of the tubing before continuing to;the next step.;6. Repeat Steps 4 - 5 with the three remaining dialysis tubes, using each of the;three remaining rubber band colors.;7. Reconstitute the sucrose powder according to the instructions provided on the;bottles label (your kit contains 60 g of sucrose in a chemical bottle). This will;create 200 mL of a 30% stock sucrose solution.;8. Use Table 2 to create additional sucrose solutions that are 30%, 15% and 3%;concentrated, respectively. Use the graduated cylinder and waste beakers to;create these solutions. Set these solutions aside.;Table 2: Serial Dilution Instructions;Sucrose;Solution;mL of Stock;Sucrose;Solution Needed;mL of Water;Needed;30%;10;0;15%;5;5;3%;1;9;3%;1;9;9. Pour 150 mL of the remaining stock sucrose solution into Beaker 1.;10. Use some of the remaining stock sucrose solution to create an additional 200 mL;of a 3% sucrose solution into Beaker 2.;Hint: Use your knowledge of serial dilutions to create this final, 3% sucrose;solution.;11. Measure and pour 10 mL of the remaining 30% sucrose solution into the dialysis;bag with the yellow rubber band. Seal the top of this tubing with the remaining;yellow rubber band.;12. Measure and pour 10 mL of the 15% sucrose solution in the bag with the red;rubber band, and seal the top of the dialysis tubing with the remaining red rubber;band. 10 mL of the 3% sucrose solution in the bag with the blue rubber band;and seal the dialysis tubing with the remaining blue rubber band. The final 10 mL;of 3% sucrose solution in the bag with the green rubber band. Seal the dialysis;tubing with the remaining green rubber band.;13. Verify and record the initial volume of solution from each bag in Table 3.;Figure 8: The dialysis bags are filled with varying concentrations of;sucrose solution and placed in one of two beakers.;14. Place the yellow, red, and blue banded tubing in Beaker 2. Place the green;banded tubing in Beaker 1 (Figure 8).;15. Hypothesize whether water will flow in or out of each dialysis bag. Include your;hypotheses, along with supporting scientific reasoning in the Hypotheses section;at the end of this procedure.;16. Allow the bags to sit for one hour. While waiting, pour out the water in the 250 mL;beaker that was used to soak the dialysis tubing in Step 1. You will use the;beaker in Step 19.;17. After allowing the tubing to sit for one hour, remove them from the beakers.;18. Carefully open the tubing. The top of the tubing may need to be cut off/removed;as they tend to dry out over the course of an hour. Measure the solution volumes;of each dialysis bag using the 100 mL graduated cylinder. Make sure to empty;and dry the cylinder completely between each sample.;19. Record your data in Table 3.;Table 3: Sucrose Concentration vs. Tubing Permeability;Band Color;Yellow;Red;Blue;Green;Sucrose;%;Initial Volume;(mL);Final Volume;(mL);Net Displacement;(mL);Hypothesis;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.;2. Which tubing increased the most in volume? Explain why this happened.;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?;4. What would happen if the tubing with the yellow band was placed in a beaker of;distilled water?;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.;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.;7. How is this experiment similar to the way a cell membrane works in the body? How;is it different? Be specific with your response.
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