BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

BIOL0601 Module 2 Assignment 1 (M2A)

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Introduction

BIOL0601 Provincial Biology

Assignment 2

Instructions:

Print Students should answer questions in the spaces provided on the paper. If you need more space, append a sheet and make sure that you clearly identify the page with your name, the assignment title and the question number. Answers to the long answer questions are to be done on a separate paper. Make sure that you clearly identify this page with your name, the assignment title and the question number.

If you are sending your file to your tutor electronically, ensure that it has a file name that includes the course name, assignment number and your name.

e.g. BIOL0601_A1_Chiu.doc (with your name in place of “Chiu.”)

Only submit your work to your tutor when all the work in the assignment (questions and labs) has been completed.

Topic Marks

Diagrams 15

Terms and Definitions 10

Short Answer Questions 29

Long Answer Questions 26

Lab 2A 10

Lab 2B 10

Total marks /100 /100

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Diagrams

1. Identify the parts of the endomembrane system on this diagram (label them A, B, C, D and E), and, in the following table, name each part and describe the function that each performs. (10 marks)

Allow ¼ mark for name of component and ¼ mark for identifying it on the diagramAllow ½ mark for function of component

NAME OF COMPONENT FUNCTION OF COMPONENTA

B

C

D

E

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 22. This is a diagram of the plasma membrane. State the function of each of the outlined parts. (5

marks)

A

B

C

D

E

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Terms

Lettered blanks have been left in the following paragraph. In the space provided, indicate the term

which should found in each blank. (10 marks)

-----A----- are a class of -----I----- found inside cells whose job it is to catalyze chemical reactions.

Generally, one -----A----- will affect one chemical reaction, so the collection of -----A----- inside a cell

will determine the -----B----- pathways available to the cell. The -----C----- is the material on which the

-----A----- acts. The -----A----- and the -----C----- form the -----D----- complex. If there is sufficient

energy called the -----E----- energy, the -----D----- complex breaks down to form -----F-----. Since the

-----A----- is not destroyed in the reaction, a single -----A----- molecule can be used many times.

Because the functioning of -----A----- depends on four levels of structure, the functioning of an -----

A----- can be adversely affected by environmental conditions such as -----G----- and -----H-----.

Extremes of these conditions cause the -----I----- to -----J----- and the -----A----- stops functioning.

A

B

C

D

E

F

G

H

I

J

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Short Answer Questions

1. Compare and contrast diffusion and osmosis. (2 marks)

Both diffusion and osmosis happen because molecules will move (diffuse) from areas of high concentration to areas of low concentration along a concentration gradient. The solute will diffuse from areas of high concentration to areas of low concentration along this concentration gradient. This will happen until the solute concentration is equal throughout the solution.

2. When a drop of blood is placed in water, the red blood cells swell and burst in process called plasmolysis. Explain how this happens. (3 marks)

3. Compare and contrast endocytosis and exocytosis. (2 marks)

4. This is a diagram of the functioning of an enzyme.

a. Name the unit indicated by the letters in the diagram: (3 marks)

a

b

c

d

e

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2f

b. Does this picture represent a decomposition or a synthesis reaction? Explain. (1 marks)

c. What special property of an enzyme is illustrated by this diagram? (1 mark)

d. Name the two environmental conditions which can affect the functioning of an enzyme (2 marks)

5. Trace the path and fate through the cell of a protein from synthesis on the ribosome to excretion from the cell. (4 marks)

6. A strand of m-RNA has the following 3 codons: UUU-CUG-GAA

a. Using Figure 21.6, identify each of the three amino acids coded for by each codon. (2 marks)

b. Diagram the complete DNA strand that would have produced this segment of m-RNA (2 marks)

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

7. Name the three types of RNA identified as t-RNA, m-RNA and r-RNA and describe how each functions within the cell. (3 marks)

8. What is a change in the base sequence of DNA called? How does this change have an effect in a cell, and ultimately in an organism. (4 marks)

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2Long Answer Questions

Answer the following questions on a separate piece of paper. Each of your answers should be two to three paragraphs long. Use your own wording.

1. Describe how the following terms relate to each other: DNA, RNA, nucleotide, nitrogenous base, deoxyribose, ribose, transcription, translation and protein. (10 marks)

2. The breakdown of glucose happens in a large number of steps in the cell, but can generally be broken down into several distinct phases. Describe what happens during each phase, and the part of the cell or cellular organelle in which each individual phase takes place. Describe where the ATP is produced in each of these phases.(10 marks)

3. The endosymbiotic hypothesis (Module 1) states that the mitochondrion may have been one of the cellular organelles acquired by assimilating another, simpler cell. What evidence do we have to support the “endosymbiosis hypothesis” (Module 1) (2 marks)

4. Describe the four levels of organization of a protein. (4 marks)

BONUS QUESTION (5 marks)

What is the relationship between glycolysis, oxygen debt and an athlete’s performance?

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Lab 2A: Investigating Tonicity

Please note that you do not need to submit your lab work to your tutor. You do need to submit the completed tables in the Results section and your answers to the questions in the Thinking About the Results section.

Introduction

In this lab, you will be studying osmosis across the membrane of potato cells. You will be creating equal sized pieces of potato and then placing the pieces in solutions with differing concentrations. You will then, over time, measure any changes taking place in size/weight of the potato pieces.

To measure changes in size, you will need either a gram scale (like a food scale) or a millimetre ruler. It is best if you have a scale that measures at least tenths of a gram. If not, then you will measure the dimensions with a millimetre ruler.

Materialspotatocoarse or sea salt or pickling salt (use table salt only if you cannot obtain the others)water (allow it to stand overnight)

Apparatusclear plastic millimetre ruler or food scale5 containers (glasses) to make salt solutionsround metal tube (about 1 - 2 cm or 0.5 inches in diameter) or a knife (in this case a French fry cutter may be a very good tool)

Method

1. Prepare your laboratory space and wear appropriate safety equipment.

2. Select 6 glass containers of the same size. Glasses will serve very nicely here. Prepare the following salt solutions:

In each container place ½ cup of water and label the containers 1 through 5a) Container 1 – add nothing to itb) Container 2 – place about 1 mL (¼ level tsp) salt into the waterc) Container 3 – place about 2 mL (2 x ¼ level tsp) salt into the water (twice as much salt)d) Container 4 – place about 3 mL (3 x ¼ level tsp salt into the water (three times as much salt)e) Container 5 – place about 4 mL ( 1 level tsp) salt into the water (four times as much salt)

3. Stir the solutions to make sure all the salt is dissolved before going any further.

4. Select a potato that is at least 10 cm (4 inches) long. Peel the potato (you may have to use more than one potato)

5. The problem here is to make pieces of potato that are, as closely as possible, of the same size or weight.

a. If you have a hollow metal tube (like a piece of copper tubing) that you can use to make potato cores, make six potato cores that are at least 10 cm long. You may also find that a French fry cutter will work. If you do not have a tube or cutter, then use a knife to make pieces of potato that are 1½ cm (¾ inch) by 1½ cm by at least 10 cm (4 inches) long.

b. If you are using a food scale, try to make the potato pieces about the same weight.

6. Cut the potato pieces into 5 cm (2 inch) lengths. Try to make sure that they are the same length and that they will fit in the glass container and be completely covered by the water/solution.

7. Record either the weight (preferable) or the dimensions of the potato pieces (bear in mind as you do this that you want to be able to measure changes in the size of the potato pieces). Place the measurements

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2in the Table 2.1.1.

8. Place the potato pieces in the labelled containers. You will make observations over the next several hours. Note the time at which the experiment was started.

9. After 30 minutes:a. Carefully remove the potato piece from the container. If you are using a scale, remove excess

solution from the surface of the potato piece before using the scale. If you are using a ruler, use the millimetre ruler to measure the dimensions of the potato core. Do the measurements as quickly as possible and replace the piece in the solution. Record the results in Table 2.1.1

b. Repeat until all the pieces have been measured.

10. Repeat the measurements after 1 hour. If the measurements are the same as the previous set, then the experiment is finished. Go to step 12

11. If the measurements are not the same, repeat the measurements again in 1 hour. You should not have to go beyond 2 hours.

12. Remove the potato pieces from the solutions. Make observations about the “feel” of the potato pieces (compared to the original potato). Use words like turgid and flaccid, hard and soft, crisp and squishy. Also note any change in colour. Record your observation in Table 2.1.2

13. Clean up your laboratory space and put equipment away. You may discard the solutions down the drain.

Results

Table 2.1.1

measurements change in measurement

container 0 0.5 1 2

A

B

C

D

E

Table 2.1.2

potato A

potato B

potato C

potato D

potato E

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Thinking About the Results

1. Define the following terms:

a) osmosis

b) isotonic

c) hypertonic

d) hypotonic

2. A selectively permeable membrane is required for osmosis to happen. Where is the selectively permeable membrane in this experiment (consider each potato cell)

3. What would you expect to happen if a cell is placed in a/n:

a) isotonic solution

b) hypertonic solution

c) hypotonic solution

4. Considering what happened to each piece of potato, describe each of the five solutions using one of the following terms: hypotonic, isotonic and hypertonic

Solution hypo / hyper / iso tonic

A

B

C

D

E

5. Considering that osmosis is the diffusion of water, explain the results recorded in Table 2.1.2

6. Why are vegetables like celery and carrots stored in water prior to serving?

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

7. Solution B is supposed to be about 0.9% salt (isotonic with the potato cytoplasm). What would this mean about the solute concentration inside the potato cells. Explain your answer.

Congratulations, you have now completed Lab 2A.

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Lab 2B: Enzymes

Please note that you do not need to submit your lab work to your tutor. You do need to submit the completed tables in the Results section and your answers to the questions in the Thinking About the Results section.

Introduction

The human body functions because of the many chemical reactions that occur to maintain it and provide for growth. Most of these reactions however, would not happen quickly enough at normal temperatures. This problem is solved by the use of biological catalysts called enzymes.

An enzyme is a protein that can speed up a chemical reaction so that it happens at a useful rate at body temperature. Every reaction that happens in the human body employs a catalyst. In this lab we will investigate the conditions required for proper enzyme function.

What would happen to your cells if they made a poisonous chemical? You might think that they would die. In fact, your cells are always making a poisonous substance. In this case the poisonous substance is called hydrogen peroxide. It is produced as the final step in cellular respiration. The cells do not die because they use an enzyme to immediately break the peroxide down into water and oxygen. The enzyme is called catalase, and in this lab we will study the action of this enzyme.

Materials3% hydrogen peroxidefresh liver

Apparatus4 pieces of pH paper (rip the long strips in half)3 small glass containersa stirrer ( glass rod, wooden skewers, toothpick or ....)

Method

1. Prepare your laboratory space and wear appropriate safety equipment.

Normal catalase activity

2. Cut the liver into small pieces (about the size of a green pea)

3. Place about 5 mL (1 teaspoon) of hydrogen peroxide in a glass container. Place a liver cube in the hydrogen peroxide. Note the rate of bubbling and how long it takes for the bubbling to stop. We will call this rate “4” on a scale of 1 to 5 (slow to fast). Record this rate in Table 2.2.1

4. When the bubbling has stopped, remove the liver cube and place it into another 5 mL of hydrogen peroxide in another glass container. Record the result in Table 2.2.1

5. (Optional) How many times can you reuse the same liver cube?

6. Repeat the previous experiment, only this time completely crush the liver cube before placing it in the hydrogen peroxide. Observe the rate and record it in Table 2.2.1

Effect of temperature on catalase activity

7. Place a cube of liver in boiling water for several minutes. (essentially cook the liver)

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 28. Remove the cube of liver from the water and place it in 5 mL of hydrogen peroxide. Observe

the bubbling and record the result in Table 2.2.2

9. Place a cube of liver in the freezer for about 1 hour. Remove the liver cube and allow it to defrost. Place the liver in 5 mL of hydrogen peroxide. Record the result in Table 2.2.2

Effect of pH of catalase activity

Place about 1 g (½ teaspoon) of baking soda in 50 mL (½ cup) of water and allow it to dissolve. Using the pH paper, measure and record the pH of the solution in Table 2.2.3

10. Place a cube of liver in the baking soda solution and allow it to stand for about 30 minutes. Remove the liver cube and place it in 5 mL (1 teaspoon) of hydrogen peroxide. Record the rate of bubbling in Table 2.2.3

11. Place 25 mL of vinegar in a glass container. Using the pH paper, measure the pH of the vinegar and record it in Table 2.2.3

12. Place a cube of liver in the vinegar for about 30 minutes. Remove the liver cube and place it in 5 mL (1 teaspoon) of hydrogen peroxide. Record the rate of bubbling in table 2.2.3

13. Clean up your lab space. Dispose of any solids in the garbage. Flush liquids down the drain with plenty of water.

Catalase in other samples

14. Test several different foods (banana, potato, carrot, other meat) for catalase activity. If you have an open cut, you may test this with a small amount of hydrogen peroxide. Record your results in Table 2.2.4

Results Table 2.2.1

rate of bubblingliver cube

liver cube (second time)

(optional) times reused

crushed liver cube

Table 2.2.2rate of bubbling

heated liver

frozen liver

Table 2.2.3pH rate of bubbling

baking soda

vinegar

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BIOL0601Provincial Biology: Module 2: Cell Biology – Activities of the Cell Assignment 2

Table 2.2.4food catalase activity

Thinking About the Results

1. Explain the result when the liver was crushed up.

2. Under what conditions do enzymes cease to function or function less effectively?

3. A body temperature of about 40 C for any length of time is considered lethal. Explain why this might be so.

4. Why would so many living things exhibit catalase activity?

Congratulations, you have now completed Lab 2B.

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