Topic Two Cells 2.4

Topic Two – Cells 2.4

1. Define the plasma membrane. A selectively permeable membrane which encloses the cell.Also known as a cell membrane.(1)

2. Draw and label a simplified (2D) diagram of the plasma membrane. Include: phospholipid bilayer, integral and peripheral proteins, glycoproteins and cholesterol. Why is it described as a bilayer?

3. List six functions of the plasma membrane.

     

4. Explain why the plasma membrane described as a fluid mosaic model.

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com State the functions of these plasma membrane components.

a. glycoproteins

b. cholesterol

5. Match the following membrane proteins with their functions:

Channel/ carrier proteins used in cell surface reactions

Protein pumps binding cells together

Receptor proteins communication between cells

Enzymes passive transport across the membrane

Adhesion proteins active transport across the membrane

Neurotransmitter receptors hormone binding and recognition

6. Draw a single phospholipid molecule. Label the hydrophobic and hydrophilic sections.

7. Explain how hydrophobic and hydrophilic properties of the phospholipid bilayer allow a membrane to maintain its structure.

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com 8. Define selectively permeable in the context of the plasma membrane.

9. Define diffusion.

Define osmosis.

10. Distinguish between solute, solvent and solution.

11. List four ways to maximize the rate of diffusion of a substance across a membrane.

12. Outline the conditions required for the following methods of membrane transport:

Selectively Concentration Membrane ATP (source of permeable gradient membrane. proteins energy)

Simple diffusion yes Yes no no

Osmosis Yes Facilitated yes diffusion

Active transport yes

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com 13. State the membrane transport methods used by the following molecules:

Water:

Non-polar molecules (with the concentration gradient):

Polar molecules (with the concentration gradient):

Any molecule against the concentration gradient:

Macromolecules:

14. Explain what is happening in this diagram:

15. Explain how osmosis can lead to plasmolysis, using a labeled diagram.

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com 16. ATP is the source of energy for active transport. Explain how ATP releases energy, using a simple diagram.

17. Distinguish between uniport, symport and antiport as different methods of active transport. A simple diagram of each will help.

18. Annotate the diagram below to show how a protein pump is used in active transport of molecules across a plasma membrane. The Na+/K+ pump is an example.

19. Define macromolecule. Give one example of a macromolecule produced in the cell.

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com 20. Definevesicle.

21. Complete and annotate the diagram below to show the process of vesicle transport of a protein molecule through a eukaryote cell. Begin with protein synthesis in the Rough ER and finish with exocytosis though the plasma membrane. Label all organelles shown.

22. Distinguish between exocytosis and endocytosis.

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com 23. Describe how the plasma membrane breaks and reforms during exocytosis and endocytosis. How does the fluidity of the membrane allow this?

24. A study was carried out to determine the relationship between the diameter of a molecule and its movement through a membrane. The graph below shows the results of the study.

[Source: Knox, et al., Biology, Mcgraw Hill, Sydney, 1994, page 65]

(a) From the information in the graph alone, describe the relationship between the diameter of a molecule and its movement through a membrane.

......

...... (2)

A second study was carried out to investigate the effect of passive protein channels on the movement of glucose into cells. The graph below shows the rate of uptake of glucose into erythrocytes by simple diffusion and facilitated diffusion.

(b) Identify the rate of glucose uptake at an external glucose concentration of 4 mmoldm-3by

(i) simple diffusion...... (1)

(ii) facilitated diffusion...... (1)

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com (c) (i) Compare the effect of increasing the external glucose concentration on glucose uptake by facilitated diffusion and by simple diffusion.

......

...... (3)

(ii) Predict, with a reason, the effect on glucose uptake by facilitated diffusion of increasing the external concentration of glucose to 30 mmoldm-3.

......

...... (2) (Total 9 marks)

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com Works Cited 1. Plasma Membrane. Dictionary.com. s.l. : Random House, 2010.

2. Allott, Andrew.IB Study Guide: Biology for the IB Diploma. s.l. : Oxford University Press, 2007. 978-0- 19-915143-1.

3. Taylor, Stephen. 2.4 Membranes (presentation). Science Video Resources. [Online] October 2010. http://sciencevideos.wordpress.com/bis-ib-diploma-programme-biology/02-cells/cell-membranes/.

Self Assessment:

Essential Biology Assessment Criterion Complete (2) Partially complete (1) Self MrT Presentation Complete and neat. All command terms NA &Organisation highlighted, tables and diagrams well presented. Academic Sources cited using the CSE (ISO 690 numerical) NA method, with Works Cited section complete and Honesty correct. Objective 1 All answers for the following command terms Most answers for the following command terms correct: correct: understanding Define Draw Label List Measure State Most answers for the following command terms Objective 2 All answers for the following command terms correct: correct: understanding Annotate Apply Calculate Describe Distinguish Estimate Identify Outline Most answers for the following command terms All answers for the following command terms correct: Objective3 correct: understanding Analyse Comment Compare Construct Deduce Derive Design Determine Discuss Evaluate Explain Predict Show Solve Sketch Suggest Logic, notation, Answers are presented in a logical and concise manner. SI units used most times, with correct mathematical NA unit symbols and definitions of terms. All working mathematical working shown. Evidence is apparent of research and reading beyond the textbook and presentations to find Further research NA correct answers to challenging questions. If any questions are unanswered, this criterion scores zero. Total (max 10):

Stephen Taylor Bandung International School http://sciencevideos.wordpress.com