CELL STRUCTURE AND PROCESSES
Grade 11 Advanced Biology
14.0 hrs.
Developed by:
Nicole Bradley
Anne Sutton
Stephanie Wood
Lesson #1 - Brief Overview
The purpose of this lesson is to introduce students to Biology, the study of cells, and the light microscope.
The following topics will be covered:
1. Scientific method
2. What is biology?
3. Reasons for studying biology
Students will also be able to explain the points of the Cell Theory. This will be accomplished by a combination of class discussion and notetaking.
In the second half of this lesson, the basic operation of the light microscope will be covered. Students will:
1. Learn the names of the various parts of the microscope with the aid of a diagram
2. Learn proper use and care of the microscope
In addition to labelling the diagram of the microscope, a chart will be constructed in order to identify the function of each part. To practice using the microscopes, an activity involving the operation of the microscope will be done. This will include:
1. Observing images under a microscope
2. Preparing diagrams based on observations
** Refer to handout # 1 for the activity.
Lesson #2 - Detailed Lesson Plan
In this lesson students will be introduced to the electron microscope, and the structure and function of cell organelles.
This lesson will begin with an overview of the electron microscope. The following will be covered:
1. Basic operation
2. Its capabilities
3. Its importance with regards to cytology
Students will be divided into groups of 2 or 3. Each student will be provided with a diagram of a plant and animal cell. Using the electron micrographs within their textbook, each group will be responsible for identifying the organelle structure on the diagrams and stating their functions.
As the students work, the teacher will circulate among the groups and pose questions to the students relating to their work. Questions such as the following will be asked:
1. What is the difference between smooth ER and rough ER?
2. What are some properties of the cell membrane?
3. How would you describe the mitochondria?
4. While pointing to some structures on the diagrams ask the students to point out one or more organelles.
Using an overhead with a pre-printed animal cell, the location, and structure of the organelles will be taken up. Each group will be asked to point out one organelle and describe its function. At the same time a student will be responsible for creating a "Part, Description, Function" (PDF) chart that will be posted in the classroom throughout the unit. While the students relay their findings of organelle function, it may be necessary for the teacher to add any important information that may have been omitted by the groups. This process will be repeated for the plant cell.
In the time remaining students will make their own PDF chart which will become a part of their notebook. Students will be notified that they will be quizzed on this material within the next few days. If time permits the teacher will ask students to close their books and quiz the students orally strictly on the function of each organelle.
Lesson #3 - Brief Overview (activity)
The purpose of this activity will be to have students investigate the differences between plant and animal cells.
Using the skills acquired from previous lesson regarding operation of the microscope, students will use prepared slides of plant and animal tissue such as protista, algae, root tip, etc., to compare and contrast plant and animal cells. Using the textbook and observing the slides students should note the following differences:
Plant Animal
-cell wall present -no cell wall
-chloroplasts present -no chloroplasts
-no lysosomes -lysosomes present
-large vacuole -smaller, more numerous vacuoles
-no centrioles -centrioles present
Student observations will serve as the basis for a class discussion regarding the differences between plant and animal cells. As a class, a note will be generated based on the points raised in the discussion.
Lesson #4 - Brief Overview (activity)
The purpose of this activity is to have the students prepare their own slides for examination using wet mounts and staining.
Students will prepare slides employing techniques such as:
1. thin-slice
2. peeling of tissue
3. staining
Students will be able to identify organelles through observing plant and animal cells. Structures such as cell walls, cholorplasts, cell membranes and nuclei may be seen.
This activity would be submitted as a formal lab report in order to assess the skills introduced thus far. As part of formative evaluation, students will be monitored while using the microscope. Their technique when preparing their slides will be observed. In the formal lab report, format will be graded along with their clearly labelled diagrams.
** Refer to handout #2 for the activity
Lesson # 5 Detailed Lesson Plan
The purpose of this lesson will be to determine the levels of organization in organisms and different types of plant and animal tissues.
At the beginning of class, a quiz on organelles will be given.
** Refer to handout #3 for the quiz
Levels of Organization
In small groups, the students will define and give examples of the following terms:
1. cell
2. tissue
3. organ
4. organ system
As a class the terms and examples will be discussed and a class set of notes will be generated.
Animal and Plant Tissues
The teacher will ask for 5 or 6 examples of animal tissues. Then notes on animal tissues will be given in the following table form:
Tissue Function Structure Location
Bone
Nerve
Blood
Muscle
5 or 6 examples of plant cells will also be asked for and the notes on plant tissue will be given in the following table form:
Tissue Function Structure Location
meristematic
parenchyma
vascular
xylem
It is important to discuss blood as a tissue because it may differ from the students preconceptions of what a tissue is. It will also be important to show the relationship of plant and animal tissues to the other levels of organization.
Lesson #6 Detailed Lesson Plan
The purpose of this lesson is for students to understand passive transport and various factors affecting passive transport.
The flow of the lesson is as follows:
1. review of types of membranes
2. defining a solution, solute and solvent
3. explaining the terms hypertonic, hypotonic and isotonic
4. describing transport processes of diffusion and osmosis
Students will then be able to predict the net movement of substances across the cell membrane in various extracellular environments and the consequences of some of these movements.
The following will be defined in note form:
1. non-permeable membrane
2. selectively permeable membrane
3. permeable membrane
Students will be asked to brainstorm example(s) of each.
The following will be defined in a note:
1. solution
2. solute
3. solvent
Students will use the above terms to create Venn diagrams
Demo:
Mix some sugar in a glass of water.
Ask the class:
1. Is this a solution?
2. What component is the solute?
3. What component is the solvent?
Explain the following terms in note format:
1. hypertonic
2. hypotonic
3. isotonic
Note: Make sure to stress that the terms are RELATIVE TO the cell(ie. a solution is hypertonic relative to the cell).
Note: Students may be able to remember the terms by thinking hypertonic(hyperactive or above), hypotonic(below) and
isotonic(equal).
To visualize these situations have some students join hands to represent a membrane and others can be Na+ ions and water molecules. Have students arrange themselves to demonstrate hypertonic, hypotonic and isotonic environments.
Review the processes of osmosis and diffusion.
Discuss the following (or other practical applications)in class:
Someone sprays perfume at the back of the classroom and after a period of time you can smell it at the front of the class. Explain what has occurred.
A grocery store owner sprays the vegetables in the store with water. Why? What happens?
Explain why a farmers crop in a drought looks droopy and shrivelled up.
Ask students, for homework, to consider what could be the consequences of the following, considering the processes of osmosis and diffusion:
1. animal cell in a hypertonic environment (shrink, dehydrate)
2. animal cell in a hypotonic environment (burst, lysis)
3. plant cell in a hypertonic environment (cell contents shrivel from cell wall
4. plant cell in a hypotonic environment (plasmolysis)
Lesson #7 Brief Overview
Students will perform a lab to investigate the effects of time and concentration on diffusion. This simple experiment will give students an opportunity to hypothesize and interpret experimental data. Students will be able to see the effects of concentration and time on diffusion first hand. During the pre-lab, the terms and homework from the previous lesson will be reviewed. Students will further develop their skills in lab report writing by submitting a formal lab report. Potato and potassium permanganate solutions are used in this experiment.
** Refer to handout #4 for complete lab materials and methods.
Lesson #8 Brief Overview
Students will learn about active transport and the effects of cell surface area to volume ratios in this lesson.
The following items will be covered when discussing active transport:
1. net movement of molecules
2. expenditure of energy
Note: Students might remember active transport requires energy by thinking that being active(ie. exercising) takes energy.
3. processes: -endocytosis(with examples)
-exocytosis (with examples)
Note: Students might remember the processes by thinking of
entrance(endocytosis) and exit(exocytosis).
Students will be asked to compare active and passive transport.
Students will then measure cubes of various sizes and calculate surface area to volume ratios. This exercise will lead students to the conclusion that as a cell(or cube) increases in size the surface area to volume ratio gets smaller. Students will then realize the significance of cell growth and transport limitations.
Lesson #9 Brief Overview
The purpose of this lesson will be to allow students to gain an appreciation of diffusion and osmosis through practical examples. In groups of two or three, students will research the common applications of diffusion and osmosis.
The following could be used as applications:
1. dialysis machines
2. food preservation
3. the effects of nicotine and alcohol on the embryo
The research will take place in the library and students will prepare a brief 5 - 10 minute presentation and a handout for the next day. Students will be required to show how one or more of the following apply to their application:
1. hypertonic
2. hypotonic
3. isotonic
4. diffusion
5. osmosis
Lesson # 10 Brief overview
The first portion of the class will be the student presentations on the diffusion and osmosis applications.
The remainder of the lesson will be a lecture on anaerobic and aerobic respiration. The terms aerobic and anaerobic will be reviewed. Each process will be described in terms of products, reactants, limitations and uses. The word equations will be given for both of the processes.
Lesson # 11 Brief overview
The purpose of this lesson will be to review concepts for the test. This activity gives the students an opportunity to review organelle structure and function. It also reviews transport processes associated with the cell. If time permits, students will participate in a review question and answer session.
** Refer to following pages for activity details
Review Activity
Build That Cell! The Teacher Resource
1. Students choose one of the following organelles from an envelope:
*cytoplasmic membrane lysosome
nucleus rough endoplasmic reticulum
nuclear membrane smooth endoplasmic reticulum
nucleolus ribosome
cytoplasm centriole
mitochondria vacuole
Golgi apparatus
2. Students will prepare a brief description about the structure and function of their organelle.
3. Students will draw a representative diagram of their
organelle.
4. Each student will compose a review question regarding their organelle.
5. One at a time, each student will approach the cell and present the organelle's description and function. Then he/she will place their diagram on the appropriate spot within the cell. The student will then pose his/her review question.
* The teacher will demonstrate this process by setting up the plasma membrane by forming it with masking tape on the floor.
6. Throughout this activity, the teacher will reinforce points by asking in-depth questions.
7. As an extension, ask students to explain what would be different if they were preparing a plant cell.
Debugged Review Activity
Build That Cell The Teacher Resource
Background Information
This activity has been designed to review cell organelle structure and function. It could also be used to introduce these concepts, if the instructions below were modified. This activity is very adaptable. You can build a plant and/or animal cell. If you do one but not the other you can point out the differences during the activity.
Set-up of the cell
There are two options for setting up the classroom for this activity. One idea is to use the entire classroom as the cell and hang the models of the organelles from the ceiling as a permanent 3-D display. Another idea would be to put masking tape on the floor to represent the cell membrane. Each student could then put the diagram in the correct location of the 'cell' using tape. It is recommended that the students doing nuclear membrane, nucleus and nucleolus work together so that these parts connect to one another in the proper manner.
Students choose one of the following organelles from an envelope:
Animal Cell:
*cytoplasmic membrane lysosome
nucleus rough endoplasmic reticulum
nuclear membrane smooth endoplasmic reticulum
nucleolus ribosome
cytoplasm centriole
mitochondria vacuole
Golgi apparatus
Plant Cell:
*cytoplasmic membrane rough endoplasmic reticulum
cell wall smooth endoplasmic reticulum
nucleus ribosome
nuclear membrane vacuole
nucleolus chloroplast
cytoplasm
mitochondria
Golgi apparatus
Pre-Lab Thinking Task
1. Students will prepare a brief description about the structure and function of their organelle.
2. Each student will compose a review question regarding their organelle.
Activity
Masking Tape Method 3-D Method
1. Students will draw a 1. Students will create a
representative diagram model of their organelle.
of their organelle.
2. Students will place their 2. Students will hang their
diagram in its appropriate model in its appropriate
place in the cell. place from the ceiling.
*3. Teacher will demonstrate *3. Teacher will demonstrate
this process by setting up this process by
the cytoplasmic membrane describing the perimeter
with masking tape on the of the room as the
floor. cytoplasmic membrane.
4. One at a time, each student will present their organelle's description and function. The student will then pose his/her review question.
5. Throughout this activity, the teacher will reinforce material by asking in-depth questions.
Extension
An idea would be to ask students to become water molecules and ions to enact hypotonic and hypertonic conditions. This could lead to demonstrations of osmosis and plasmolysis.
Justifications for Activity Changes
An optional 3-dimensional method was added because in reality cells are 3-dimensional, not 2-dimensional as some students perceive from studying textbook diagrams. The 3-dimensional nature of a cell may be more evident by using 3-dimensional models in the activity especially for kinaesthetic and visual learners. The masking tape method was still included as an option in the debugged activity to give the teacher a choice.
The preparation of the activity was assigned as a pre-lab thinking task to ensure students were prepared for the activity in lesson #11. This was also done so students could plan in advance their models or diagrams in case materials needed to be brought into class from home.
The extension where students assume the roles of water molecules and ions was added to aid students with the concepts of osmosis and diffusion. This covers more unit material as a review for the test.
Due to the difficulty of having the nucleus, nuclear membrane and nucleolus being created by 3 different students their relative sizes could be out of proportion. To solve this problem, 3 students will work together on these organelles.
Lesson # 12 Brief Overview
This period consists of a unit test which checks comprehension of unit material.
** Refer to the following pages for the unit test.
NAME:
DATE:
Cell Biology Test
1. In the spaces provided on the next page, write the names of the parts indicated from the following diagrams.
1.
/10
A ________________________ F _______________________
B ________________________ G _______________________
C ________________________ H _______________________
D ________________________ I _______________________
E ________________________ J _______________________
/5 2. State the functions of the following parts from above:
A
B
C
E
G
/4 3. State the four main differences between plant and animal cells.
4. Compare and contrast the following terms:
/2 a. active and passive transport
/2 b. hypertonic and hypotonic
/2 c. aerobic and anaerobic respiration
/2 d. osmosis and diffusion
/2 5a. Define the process of diffusion.
/1 b. How does the concentration of a substance influence the extent to which the substance diffuses?
/2 6. Why does the growth rate of a cell slow down as it gets larger?
7. Tom sprays cold water on the vegetables in his grocery store.
/2 a. Explain what happens over the next few minutes.
/1 b. Why would Tom use such a procedure?
/2 8a. Define tissue and organ and differentiate between them.
/3 b. Describe a plant or animal tissue in terms of structure, function and location.
/3 9. Explain an application of osmosis and/or diffusion from the class presentations.(Need three important distinct points for full marks!)
Total marks: /43
NAME:
DATE:
Cell Biology Test- Answer Key
1. In the spaces provided on the next page, write the names of the parts indicated from the following diagrams.
1.
/10
A chloroplast F nucleolus
B cell wall G rough endoplasmic
reticulum
C mitochondrion H Golgi apparatus
D cytoplasm I cell membrane
E nuclear membrane J centrioles
/5 2. State the functions of the following parts from above:
A produces food by photosynthesis
B supports and protects plant cells
C produces energy for the cells
E surrounds the nucleus and controls the passage of materials into and out of the nucleus
G transports material within the cell
/4 3. State the four main differences between plant and animal cells.
- four of the following five:
Plant Animal
have cell wall don't have cell wall
have chloroplasts don't have chloroplasts
don't have centrioles have centrioles
large, central vacuole small, numerous vacuoles
don't have lysosomes have lysosomes
4. Compare and contrast the following terms:
The following are sample answers:
/2 a. active and passive transport
comparison- both involved in the transport of materials
active transport- requires energy
passive transport- no energy required
/2 b. hypertonic and hypotonic
both are cell environments
hypertonic-higher concentration of solutes
hypotonic- lower concentration of solutes
/2 c. aerobic and anaerobic respiration
both are methods of obtaining energy
aerobic- requires oxygen
anaerobic- doesn't require oxygen
/2 d. osmosis and diffusion
both are methods of passive transport
osmosis is the diffusion of water only
diffusion is the transport of any substance from an area of high concentration to an area of low concentration
/2 5a. Define the process of diffusion.
Diffusion is the random motion of a substance from an area of high concentration to an area of low concentration of that substance.
/1 b. How does the concentration of a substance influence the extent to which the substance diffuses?
The more concentrated the substance, the higher the rate of diffusion.
/2 6. Why does the growth rate of a cell slow down as it gets larger?
The surface area to volume ratio gets smaller as the volume gets larger. Cells require surface area to get food and materials into the cell. As the surface area to volume ratio decreases when the cell grows larger, there is not enough surface area for the cell to diffuse its necessary materials across the cell
membrane and the growth slows down.
7. Tom sprays cold water on the vegetables in his grocery store.
/2 a. Explain what happens over the next few minutes.
Osmosis occurs and water diffuses across the cell membranes in the vegetables. This diffusion causes the cells, and therefore the vegetables, to become larger and turgid.
/1 b. Why would Tom use such a procedure?
The firm vegetables would appear more attractive to customers and they would buy them.
/2 8a. Define tissue and organ and differentiate between them.
A tissue is a group of cells that are similar and organized into a functional unit. An organ is a body part composed of specialized tissue performing a specific function.
/3 b. Describe a plant or animal tissue in terms of structure, function and location.
1 mark each for structure, function and location
eg. blood, carries oxygen, found in the circulatory system
/3 9. Explain an application of osmosis and/or diffusion from the class presentations.(Need three important distinct points for full marks!)
- dependant on class presentations
Total marks: /43
** Handout #1
Activity - Operating the Compound Light Microscope
Materials
newspaper microscope slides
dropper cover slip
compound light microscope
Procedure
1. Review the parts of the microscope and how to use it properly.
2. Cut out the letter "e" from a page of the newspaper. Try to find one that had no printing or pictures on the other side of the paper. Place the letter "e" on the microscope slide and put a drop of water on it. Using a cover slip at a 450 angle, cover the with it.
3. Place the "e" right side up on the microscope stage and secure the slide with the stage slips.
4. Examine the slide through the following steps:
a) Make sure that the low-power objective is in the viewing position and that the body tube is at its highest position.
b) Looking at the microscope from the side, turn the coarse adjustment knob so that the objective lens moves down toward the stage. Keep turning until there is the least possible distance between the lens and the stage.
c) Look through the ocular and slowly turn the coarse adjustment knob so that the objective lens moves away from the stage. As you turn the coarse adjustment knob, you will see the "e" coming into focus. It may be slightly off to one side. If so, move the slide so that the "e" is in the centre of your field of view. Use the fine adjustment knob to obtain a sharper image.
d) Sketch the letter "e" as it appears in the field. NOTE: If your specimen begins to dry, add another drop of water to the edge of the cover slip.
e) Practice moving the slide in different directions (left, right, away from you, and toward you). Observe and record how the image moves in each case.
f) Move the image back to the centre of the field of view. Rotate the revolving nosepiece so that the medium-power objective lens is in the viewing position. At higher magnifications, use only the fine adjustment knob to focus the image. Compare your observation of the "e" at medium-power magnification with your observation at low-power magnification. Record your observations as you did for d). NOTE: If your microscope does not remain in focus when you switch to a higher magnification, repeat the procedure starting with step 3b).
g) Rotate the nosepiece to the highest magnification. Again use only the fine adjustment knob to focus. Record your observations of the "e" at high-power magnification.
Observations - Numbers correspond to the Procedure steps.
3 d,f,g)
Low-Power Medium-Power High-Power
e)
Actual Direction Moved Observed Direction of Movement
Questions
1. Why should the specimen being viewed through the microscope be centred in the field of view before you increase the magnification?
2. How did the "e" appear when you examined it through the microscope? What did you notice when you moved the letter "e" around on the microscope stage? Explain what these observations tell you about what happens to the light as it travels from the specimen through the objective and ocular lenses to your eye.
3. How would you move a microscope slide on the stage in order to bring a specimen in the upper right-hand area of the field of view to the centre?
** Handout #2
Activity - Preparing Slides
Preparing a wet mount:
1. Clean slide and coverslip.
2. Put specimen on slide.
3. Place 1-3 drops of water on specimen. If staining is required it is applied here also by drops.
4. Slide coverslip at a 450 angle along the slide surface and drop onto specimen once medium has spread across the coverslip.
Part A - Examining cork
Method
1. Using a thin slice of cork, prepare a wet mount of the cork.
2. Examine under the microscope and draw a labelled diagram below.
Observations
Part B - Examining cheek tissue
Method
1. Using a toothpick scrape the inside of your cheek gently to obtain some cheek tissue.
2. Prepare a wet mount using this tissue. Stain this using methylene blue stain.
3. Examine your preparation under the microscope and draw a labelled diagram below.
Observations
Part C - Examining geranium leaf
Method
1. Prepare a wet mount of a geranium leaf.
2. Observe under high and low-power.
3. Stain the leaf with iodine.
4. Examine again, and draw a labelled diagram below.
Observations
Part D - Examining onion cells
Method
1. Obtain an outside sample of an onion. Be careful not to take the onion skin.
2. Teacher will demonstrate how to obtain a tissue sample.
3. Prepare a wet mount using iodine as the stain.
4. Examine your preparation and draw a labelled diagram below.
Observation
** Handout #3
Organelle Quiz
Name:
Give the name of the organelle described below:
1. controls passage of materials into
and out of the cell
2. digests food using enzymes
3. produces energy for the cell
4. system of folded membranes found in
cell cytoplasm, transports substances
5. controls all functions of the cell
6. stores food, water and other materials
within a cell
7. contain chlorophyll
8. assemble proteins for the cell
9. semi-rigid container composed of
cellulose
10.controls passage of materials into
and of the nucleus
/10
Organelle Quiz Answer Key
1. cell membrane
2. lysosome
3. mitochondrion
4. endoplasmic reticulum
5. nucleus
6. vacuole
7. chloroplast
8. ribosome
9. cell wall
10. nuclear membrane
/10
** Handout #4
Diffusion Lab
Materials
potato metric ruler
scalpel potassium permanganate solutions:
4-250 mL beakers -5%
-1%
tweezers -0.1%
cork borer
Part 1 Diffusion and Time
Procedure:
1. Using the cork borer remove a core from a potato.
2. Cut this core into 5 equal lengths. (Use a ruler!)
3. Fill a 250 mL beaker to the 100 mL mark with 5% potassium permanganate solution.
4. Record the time and place 4 potato pieces into the solution.
5. Remove 1 piece every 10 minutes using tweezers and place on paper towel.
6. Using a clean scalpel cut each piece in half.
7. Measure the distance in mm that the solution has diffused into each potato piece and record in a data table.
8. The potato piece not put into solution acts as a control. It will be considered as piece #1 - 0 minutes.
Part 2 Diffusion and Concentration
Procedure:
1. Using a cork borer remove a core from a potato.
2. Cut the bore into three equal pieces.
3. Set up 3-250 mL beakers as follows:
beaker #1 - 50 mL of 5% potassium permanganate
beaker #2 - 50 mL of 1% potassium permanganate
beaker #3 - 50 mL of 0.1% potassium permanganate
Label each beaker as to concentration.
4. Place 1 potato piece into each beaker and record time.
5. After 40 minutes remove the pieces using tweezers and place on paper towel.
6. Cut the pieces in half and measure the distance in mm that the solution has diffused into each potato piece and record in data table.
Note: Part 1 and 2 could be combined to save time (ie. add 4 potato pieces from part 1 to 5% potassium permanganate beaker in part #2 and take out at 10 minute intervals). Also, diffusion and temperature could be incorporated into this lab if time permitted.