To study cells, biologists use microscopes and the tools of biochemistry [2].

Transcription

1 GUIDED READING - Ch. 6 - THE CELL NAME: Please print out these pages and HANDWRITE the answers directly on the printouts. Typed work or answers on separate sheets of paper will not be accepted. Importantly, guided readings are NOT GROUP PROJECTS!!! You, and you alone, are to answer the questions as you read. You are not to share them with another students or work together on filling it out. Please report any dishonest behavior to your instructor to be dealt with accordingly. Get in the habit of writing legibly, neatly, and in a NORMAL, MEDIUM-SIZED FONT. AP essay readers and I will skip grading anything that cannot be easily and quickly read so start perfect your handwriting. Please SCAN documents properly and upload them to Archie. Avoid taking photographs of or uploading dark, washed out, side ways, or upside down homework. Please use the scanner in the school s media lab if one is not at your disposal and keep completed guides organized in your binder to use as study and review tools. READ FOR UNDERSTANDING and not merely to complete an assignment. Though all the answers are in your textbook, you should try to put answers in your own words, maintaining accuracy and the proper use of terminology, rather than blindly copying the textbook whenever possible. To study cells, biologists use microscopes and the tools of biochemistry [2]. 1. The study of cells has been limited by their small size, and so they were not seen and described until 1665, when Robert Hooke first looked at dead cells from an oak tree. His contemporary, Anton van Leeuwenhoek, crafted lenses; and with the improvements in optical aids, a new world was opened. Magnification and Resolving Power limit what can be seen. Explain the difference and the importance of each in biology. [2] 2. a. Explain how a light microscope works.

2 b. What are some of the advantages and disadvantages of using a light microscope? a. Light Microscope: b. c. Contrast: d. 3. a. How does an electron microscope work? b. What is the difference between a scanning and transmission electron microscope? [1] c. Study the electron micrographs in your textbook. Describe the different types of images obtained from scanning electron microscopy (SEM) and transmission electron microscopy (TEM)? [2] d. The development of electron microscopes has further opened our window on the cell and its organelles. What is considered a major disadvantage of the electron microscopes? [2] 4. Which type of microscope would you use to study [2] a. A living macrophage immune system cell? b. The internal structure of the mitochondria organelle? c. The surface area of intestinal cells?

3 5. a. Explain the purposes of cell fractionation. b. Explain the step-by-step process of cell fractionation. c. Which cellular structures and/or organelles are the smallest ones isolated in this procedure? [2] Eukaryotic cells have internal membranes that compartmentalize their functions. [2] 6. Which two domains consist of prokaryotic cells? [2] 7. A major difference between prokaryotic and eukaryotic cells is the location of their DNA. Describe this difference. [2]

4 8. a. On the illustration of a prokaryotic cell, identify the following prokaryotic cell components. [1] f. e. (the middle coating) c. (the purple region) a. (the outermost coating) b. (the floating dark dots) d. (the innermost coating) g. b. Explain the function of each of the parts labeled above [2].

5 9. What is the definition and difference between the cell s cytosol and cytoplasm? 10. a. Why can t a cell be infinitely small? b. Explain how the surface area to volume ratio of a cell imposes a limit to cell size? 11. Describe how many neurons and intestinal cells each have greatly increased surface area. [2] The eukaryotic cell s genetic instructions are housed in the nucleus and carried out by the ribosomes. [2] 12. Briefly explain the benefit(s) of dividing the cell into compartments (organelles).

6 13. List the organelles NOT found in Plant cells but found in Animal cells. 14. List the organelles NOT found in Animal cells but found in Plant cells. When studying organelles, pay special attention to the structure and function of the organelles or the parts of the organelles. Make sure you see how the specific structure allows the specific function to happen! 15. The nucleus is the organelle that contains MOST of the genes in eukaryotic cells (mitochondria have some DNA with genes too). On the figure below, label the nuclear envelope, nuclear pore, and pore complex. 16. a. Describe the function of the nuclear envelope. b. How many membrane layers thick is it? [2] c. What connects the layers? [2] 17. Describe the function of the following thee parts of the nucleus. a. Pore Complex.

7 b. Nuclear Lamina. c. Nuclear Matrix. 18. a. Found within the nucleus are the chromosomes. They are made of chromatin. What are the two components of chromatin? [2] b. What are chromosomes? c. When do the thin chromatin fibers condense to become distinct chromosomes? [2] 19. a. When are the nucleoli (nucleolus, singular) visible? [2] b. What is being made and assembled here and how? [2] 20. a. What are ribosomes?

8 b. What are their two components? [2] c. All ribosomes in an organism s cell(s) are the same, but we distinguish between two types of ribosomes based on where they are found and the destination of the protein product made by them. What is the difference in location between free and bound ribosomes? [2] d. What is the difference in the product made by free and bound ribosomes (include three types protein categories made by bound ribosomes)? [2] The endomembrane system regulates protein traffic and performs metabolic functions in the cell. [2] 21. a. List all the structures that make up the endomembrane system. [2] b. Where do the membranes of these structures come from? c. Are the membranes of the organelles of the endomembrane system identical to each other and if not in what ways can they differ? d. Can the composition of individual membranes be altered throughout the lifetime of a cell?

9 22. a. The endoplasmic reticulum (ER) makes up more than half the total membrane system in many eukaryotic cells. Use this sketch to identify the lumen or cisternal space, cisternae, and transport vesicles. [2] b. Explain briefly what each of these three terms describe. 23. a. Describe the difference in appearance between the smooth and rough ER. b. List and describe three main functions of the Smooth ER {2]. c. Describe two main functions of Rough ER.

10 24. Why does alcohol abuse increase tolerance to other drugs such as barbiturates? [2] 25. a. As proteins are synthesizes, they are threaded from the bound ribosomes into the lumen of the rough ER. Some of these proteins form glycoproteins. What is a glycoprotein? [2] b. What does the ER do with these and other secretory proteins? [2] 26. The transport vesicle formed from the rough ER fuse with the Golgi apparatus. Use this illustration to label the cisterna of the Golgi and its cis and trans faces. 27. Describe the functions of the Golgi apparatus. a. What are lysosomes?

11 b. What do they contain? [2] c. What is their ph? [2] 28. If a lysosome happens to burst open inside the cell, the cell contents are not immediately digested. This is possible only if a significant number of lysosomes release their content into the cell, which would then autodigest itself. Why would the cell not autodigest with the release of just one lysosome s contents? 29. a. How do lysosomes get made (explain for both their membrane and their internal hydrolytic enzymes)? b. One function of lysosomes is intracellular digestion of particles engulfed by phagocytosis. Describe this process of digestion. [2]

12 c. Which human cells carry out phagocytosis? [2] d. A second function of lysosomes is to recycle cellular components in a process called autophagy. Describe this process. [2] 30. Explain how lysosomes play a crucial role in the cause of Tay-Sachs disease. 31. a. What are vacuoles? b. Describe the function of the following three types of vacuoles. [2] i. Food Vacuoles

13 ii. Contractile Vacuoles iii. Central Vacuoles in Plants (include at least three functions and materials stored in these) 32. What is the name of the solution inside a plant cell s central vacuole? Why is it different from the solution in the cytoplasm? 33. Show off your knowledge. Use the figure below to explain in detail how the elements of the endomembrane system function together to secrete a protein. You must include explanations of what happens to the protein throughout its voyage through all relevant organelles, starting from the moment a polypeptide s primary structure of amino acids is built by the bound ribosomes. Label in Box #1 and explain in box #2 continued on next page!

14

15 Mitochondria and chloroplasts change energy from one form to another. [2] 34. a. Mitochondria and chloroplasts are not considered part of the endomembrane system, although they are enclosed by membranes. Sketch a mitochondrion here and label its outer membrane, inner membrane, inner membrane space, cristae, matrix, and mitochondrial ribosomes. [2] b. Define the following mitochondrial structures. [1] i. Cristae ii. Mitochondrial Matrix 35. Describe the main function of Mitochondria. [1] 36. What do the following plastids do? a. Amyloplasts b. Chromoplats c. Chloroplasts

16 37. a. Sketch a chloroplast here and label its outer membrane, inner membrane, intermembrane space, thylakoids, granum, and stroma. Notice that the mitochondrion had two membrane compartments while the chloroplast has three compartments. [2] b. Define the following chloroplast structures. [1] i. Thylakoids ii. Grana iii. Stroma 38. Describe the main function of the chloroplast. 39. a. Recall the relationship of structure to function. Why is the inner membrane of the mitochondria highly folded? What role do all the individual thylakoid membranes serve? (Same answer for both questions.) b. Chloroplasts and mitochondria both have ribosomes and their own DNA. You will learn later about their evolution, but for now hold onto these facts. They are semiautonomous organelles that grow and reproduce within the cell. And you re lucky today there is not a question here!

17 40. a. What happens in peroxisomes? b. What are some functions of peroxisomes? c. If peroxisomes are not part of the endomembrane system, how do new peroxisomes form? The cytoskeleton is a network of fibers that organizes structures and activities in the cell. [2] 41. What is the cytoskeleton? [2] 42. What are the three roles of the cytoskeleton? EXPLAIN each. [2]

18 43. Compare and contrast the three types of cytoskeletal filaments. Be sure to include a mention of each ones 1. name, 2. structure, 3. diameter, and 4. composition. [1] 44. Microtubules are made of tubulin which is a dimmer made up of two subunits. These are easily assembled and disassembled. What are the four functions of microtubules? [2]

19 45. a. Animal cells have a centrosome that contains a pair of centrioles. Plant cells and yeast cells do not have centrioles. What is another name for centrosome and what is their role believed to be? [2] b. What is the composition / make up of a centriole? c. Make a sketch that shows the arrangement described in part b. in cross section. [2] 46. Compare and contrast the functioning of flagella and cilia. In AP Biology, you are expected to answer the EXACT question asked. This is a specific instruction that means you are to tell 1. how they are alike - compare and 2. tell how they are different - contrast. Remember this for similar phrases on exams. [2]

20 47. Cilia and flagella are also composed of microtubules. The arrangement of microtubules is said to be 9+2. Make a sketch of a cross section here. [2] 48. Explain the structure and role of basal bodies. 49. Dynein is a motor protein involved in the movement of cilia and flagella. How do dyneins assist in making cilia and flagella work? Be sure to also mention the role of ATP in this movement. [2]

21 50. Microfilaments are solid and are made up of double chains made of the globular protein actin. What are six functions of microfilaments or actin filaments? [2] 51. What are the motor proteins that move actin microfilaments? [2] 52. Explain the details of how myosin motors assist in the following muscle contraction, cell movement, and plant cytoplasmic streaming? You may include a drawing but a drawing cannot be the bulk of your answer.

22 53. a. What is a pseudopodia? b. Name two eukaryotic cell examples that move by crawling and extending pseudopodia. 54. What is cytoplasmic streaming then and what is its purpose? 55. Intermediate filaments are made of coiled keratin proteins. They are bigger than microfilaments but smaller than microtubules. They are more permanent fixtures of cells. What are three functions of intermediate filaments? [2] Extracellular components and connections between cells help coordinate cellular activities. [2] 56. a. What is a plant s cell wall? b. What other domains or kingdoms of organisms have cell walls surrounding their cells? c. What are three functions of plant cell walls? [2]

23 d. What is the composition of the cell wall and how is it made? [2] 57. What is the plant s primary cell wall? 58. a. What is the middle lamella and what is it made of? [2] b. Where is it found? [2] c. What is its purpose? 59. What is a secondary cell wall? Explain the deposition of this secondary cell wall. [2] 60. On the sketch, label the primary cell wall, secondary cell wall, middle lamella, cytosol, plasma membrane, central vacuole, and plasmodesmata. [2]

24 61. Animal cells do not have cell walls, but they do have an extracellular matrix (ECM). On this figure, label the elements indicated, and then explain the role of each in the boxes below. [2]

25 62. Four intercellular junctions exist between eukaryotic cells. Identify and describe the role of the intercellular junctions found in plant cells? What is able to pass from one cell to another through the use of these plasmodesmata? 63. Animal cells do not have plasmodesmata. This figure shows the three types of intercellular junctions seen in animal cells. Label each. Then summarize their role and importance in the three boxes below.

26 64. Here is a great chart to summarize three concepts STUDY IT!

27 65. Please answer the Self-Quiz at the end of your chapter. Do your best to try it from memory first in order to test how well you grasped the material References 1. Adapted from L. Miriello 2. Adapted from Fred and Theresa Holtzclaw