Cells and Cell Processes
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Unit Rationale
The National Science Standards list “structure and function in living systems” as a life science
standard for grades 5-8 (National Science Education Standards, 1996, page 106), establishing the
study of cells as a fundamental body of knowledge for all middle school students. Knowledge of
cells and cellular processes is fundamental to understanding the human body and the diseases
that affect it. Acquiring an understanding of the ramifications that chemicals such as drugs and
alcohol have upon the cells of the human body is important, particularly since middle school
students are often at risk for experimenting with drugs and alcohol. The study of cells also builds
the foundation for molecular biology which students will be exposed to in high school.
Unit Goals

Content Knowledge: Students will be able to
o Explain how the invention of the microscope contributed to knowledge about
living things
o Identify the parts of the microscope and their functions
o Know that cells are the smallest unit of life
o Identify the levels of organization from cell to organism
o Know that Robert Hooke discovered cells
o Explain how cells arise from pre-existing cells (cell theory)
o Describe the functions of cell organelles, cell wall, and cell membrane
o Describe three types of cells (bacteria, plant, animal)
o Describe the major differences between plant and animal cells
o Define osmosis and diffusion
o Explain how molecules cross a cell membrane
o Explain how a cell divides and its importance to cells
o Describe the events that take place during a cell’s life cycle

Science Process Skills: Students will be able to
o Use a microscope to properly focus an object using both low power and high
power
o Correctly assemble a wet-mount slide
o Correctly measure circumference
o Accurately mass an object
Unit: Cells and Cell Processes
Pennsylvania Standards for Science and Technology
The following Pennsylvania Standards will be addressed during the unit
3.1.6.A4
Recognize that all organisms are composed of cells and that many organisms are
unicellular and must carry out all life functions in one cell
3.1.6.A6
Identify examples of unicellular and multi-cellular organisms
3.1.6.A8
Explain why the details of most cells are visible only through a
microscope
3.1.7.A2
Describes how organisms obtain and use energy throughout their lives
3.1.7.A4
Explain how cells arise from pre-existing cells
3.1.7.A5
Explain how the cell is the basic structural and functional unit of living things
3.1.7.A6
Identify the levels of organization from cell to organism
3.1.7.A7
Compare life processes (e.g. growth, digestion) at the organism level with life
processes at the cellular level
Learner Characteristics
This unit is designed for middle school students, ages 11-14, and can be used with special
education, regular education, and gifted education students. Students in this age group are
experiencing the onset of puberty, a period which brings about great developmental changes
physically, socially, cognitively, and emotionally. Large physical changes, including growth in
height, weight, and the appearance of secondary sex characteristics occur. Socially, adolescence
often brings about a desire for independence from family and a stronger need for peer
acceptance. Recent studies have shown that the parts of the brain that control behavior and
cognition grow at different rates, making adolescence a critical time of development (Steinburg,
2005). Some adolescents choose this stage in their life to experiment with drugs, alcohol, or sex,
all of can which pose series health issues for the individual. Although adolescence marks the
stage where a learner is able to think abstractly, because cognitive growth is sporadic, it is
important to continue to provide concrete hands-on learning experiences with multiple learning
approaches (NMSA, 2010).
Student’s Present Education Levels
This unit presumes no prior knowledge of microscopes, cells, or cellular function. Although
individual students vary in their abilities, students should be able to read at the 5th grade level or
above, work independently when directed, work cooperatively with others in a laboratory or
group setting, and follow verbal and written directions.
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Unit: Cells and Cell Processes
Students are expected to be able to properly use a triple beam balance and to be able to read a
measuring tape to the nearest tenth of a centimeter. The compound microscope will be
introduced during the unit; students must be able to follow directions for learning how to
properly focus a microscope. Accommodations will be made for any student with vision
impairment (ex. magnified images available in print or project onto a white board).
Technology skills include the ability to turn a computer on and off, to use a mouse to access the
Internet and navigate to designated web sites, and to click within websites to activate interactive
portions of the site.
Classroom Layout and Student Groups
Lessons should be taught in a science laboratory equipped with at least six lab stations that
contain electricity and running water. Optimally, there should be no more than 24 students in
each class to provide adequate supervision and ensure student safety (NSTA Position statement,
n.d.). Students should be assigned to cooperative groups of four students per lab table. Each
student will work with between one to three partners at the table to share microscopes, triple
beam balances, and computers. Groups should be rearranged throughout the year to ensure each
student has an opportunity to work with all other students.
Unit Introduction
A lesson called “Is it Alive?” will be used to introduce the Cells and Cell Processes Unit

Directions:
o Light a candle. Pose the question “Is the flame alive?” Allow students to voice
their opinion but do not give them the answer
o Give students the definitions of living, non-living, and dead
o Provide students with a box of materials (see lab materials list). Working in
groups of four, have students classify the objects as either living, non-living, or
dead
o Lead a discussion to have students decide which characteristics are common to
objects they classified as “living” or “dead”
o Explain to students that all living or once living objects are made up of something
called cells
o Revisit the idea of the candle’s flame. Tell students that it does not have cells.
Have them classify it as living, non-living, or dead
o Tell the students that they will be learning about cells and cellular processes
during the next several weeks
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Unit: Cells and Cell Processes
Materials and Media

Student Text and Teacher Resources
The text is available through Prentice Hall Publishers. Each student will be provided with
a text so that they will be able to complete the readings and have a resource throughout
the unit
o Student Text: Science Explorer Cells and Heredity
Publisher: Prentice Hall, 2004
ISBN 0-13-115088-X
o Teacher Resources
All in One Teaching Resources, Cells and Heredity (Prentice Hall Science
Explorer)
Publisher: Prentice Hall, 2004
ISBN: 013190275X

Technology Equipment
Computers running Windows XP and Microsoft Office will be utilized for student
research, word processing, and spreadsheets throughout the Cells and Cell Processes
unit

Lab Materials
All materials listed are utilized to conduct hands-on lab activities designed to promote
learning and to assist students in making connections with the content. Materials listed
are designated for two to four students
o Materials for Introduction to Microscope
Compound microscopes with 4x, 10x, 40x magnification
Cover slips
Microscope slides
Newspaper
Water
Scissors
Pond water
Prepared slides of tissues
o Materials for “Is It Alive?” Lab Activity
Pine cone
Pencil
Mushroom
Carrot
Seeds
Jar of Water
Bag of soil
Twig from a tree
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Unit: Cells and Cell Processes
Feather
Paper
Paper Clip
o Materials for Egg Osmosis Lab
Triple Beam Balance
One raw egg
Cup that will hold egg and vinegar
200 ml Vinegar
Measuring tape
200 ml tap water
200 ml liquid of student choice
200 ml Salt water
Calculators
o Materials for Cell Survey
Compound Microscope
Several microscope slides and cover slips
Dropper bottle with water
Prepared slides: bacteria shapes and various animal tissues
Yeast solution
Fresh Elodea leaf
Onion
Potato slice
Banana slice
Piece of red pepper or carrot
Plastic knife

Web Sites that Support Instruction
Sites listed below are designed to promote scientific inquiry and to provide content
information about microscopes and cells
o Introduction to the Microscope
This website is an excellent source of basic information regarding microscope
parts, use, and care. It can be used as an introduction to microscopy
http://www.cas.muohio.edu/mbi-ws/microscopes/compoundscope.html
o Interactive Online Microscope
Students can be introduced to this site prior to experiencing the microscopes
http://www.udel.edu/biology/ketcham/microscope/scope.html
o Interactive Lab: Identifying Phases of Mitosis
This website features an activity in which students calculate the percentage of
time a cell spends in each phase of mitosis. Cell structures are easier to find than
using a prepared slide of onion root tips
http://www.biology.arizona.edu/cell_bio/cell_bio.html
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Unit: Cells and Cell Processes
o Cells Alive Website
This site features good background information about cells, including a discussion
of mitosis. A cell gallery of cell pictures is also useful in helping students
visualize different types of cells, their shape, and their function.
http://www.cellsalive.com/

Videos from Discovery Education
Available from http://www.discoveryeducation.com. All videos supplement topics
related to microscopes and cells
o The Incredible World of the Microscope (20 min)
This film shows a variety of organisms as viewed under the microscope, explains
how the microscope works and why the microscope is a valuable tool. It is a good
way to introduce microscopes to pique student interest
o How to Use a Microscope (26 min)
This film provides students with information about the history of microscopes,
their proper use, and explains how to prepare a wet mount slide
o Assignment Discovery: Cells (25 min)
The video depicts magnified images of cells and explains the difference between
plant and animal cells
o Introducing the Cell (21 min)
This video serves as a good introduction to the cell theory and explains how cells
are organized into tissues. Examples of one-celled organisms, plant and animal
cells are shown

Community Resources:
Digital Microscopes
Ron Faust, Educator for Science in Motion, Ursinus College. Students are able to
use state-of-the-art digital microscopes through this state funded equipment loan
program
http://academic.ursinus.edu/scienceinmotion/About/About_Mission.html
Lesson Topic: Introduction to Digital Microscopes
Visuals

Microscope
o Labeled picture of microscope
o The picture will help students learn the parts of the microscope in preparation for
using the microscope in the lab
o Objective(s) Visual will Address: Identify the parts of the microscope and
their functions; use a microscope to properly focus an object using both
low power and high power
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Unit: Cells and Cell Processes

Robert Hooke’s Contribution
o A picture of Robert Hooke’s microscope and things that Robert Hooke saw
o The purpose of the picture is to explain how the term “cell” got its name and to
show the person who first defined cells
o Objective(s) Visual will Address: Know that Robert Hooke discovered cells

Cell Theory
o Timeline showing the development of the cell theory including the major
scientists, times of discovery, and important aspects of the theory
o Students need to understand that all cells arise from previous cells
o Objective(s) Visual will Address: Explain how cells arise from pre-existing cells

Levels of Cellular Organization
o A graphic that shows the levels of cellular organization from cell or organism
o Students will understand that the smallest unit of life is the cell and will see the
relationship between cell, tissue, organ, organ system, and organism
o Objective(s) Visual will Address: Identify the levels of organization from cell to
organism

Types of Cells
o Graphic depicting a typical bacterial cell, a plant cell, and an animal cell
o The visual will be beneficial to all learners in understanding the differences
between these three types of cells
o Objective(s) Visual will Address: Describe three types of cells (bacteria, plant,
animal); Describe the major differences between plant and animal cells

Diffusion
o Graphic showing a cell with molecules both inside and outside of cell with an
arrow showing movement of those molecules as they would occur during
diffusion
o Diffusion is an abstract concept for most middle school students; a graphic
representation will promote understanding of the concept, particularly for visual
learners
o Objective(s) Visual will Address: Define osmosis and diffusion; Explain how
molecules cross a cell membrane

Osmosis
o Graphic showing the direction of movement of water into and out of a cell
membrane as determined by concentration of water
o The visual will help students visualize that concentration of water outside a cell
determines the direction water moves across a membrane
o Objective(s) Visual will Address: Define osmosis and diffusion; Explain how
molecules cross a cell membrane
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Unit: Cells and Cell Processes

Mitosis
o Graphic showing labeled phases of mitosis
o Mitosis is an abstract concept for middle school students; having the process
displayed in a visual manner will promote student understanding
o Objective(s) Visual will Address: Explain how a cell divides and its importance to
cells; Describe the events that take place during a cell’s life cycle
Assessment
A variety of instruments will be used to assess both content knowledge and process skills.
Content knowledge will be assessed throughout the unit using worksheets that accompany the
text and weekly quizzes to evaluate student progress. These formative assessments will be
utilized to determine if remediation is needed. A unit test will be administered at the end of the
unit that will include all content knowledge and prepare students for the state science assessment.
Lab activities will be utilized to teach science process skills while developing an understanding
of cells and cell processes. Lab reports, including analysis questions, graphs, and conclusions
will be assessed.
Unit assessments will include:

Quizzes
o Microscope parts and their function
o How to focus a microscope
o Cell Organelles
o Cell Theory
o Diffusion/Osmosis
o Mitosis

Lab Practical
o A lab practical will be administered in which students will be expected to
correctly focus an object under high power in 90 seconds or less. This will be a
quiz designed to assess science process skills

Unit Test
o A test covering all quiz topics will occur at the end of the unit as a summative
assessment and as preparation for the PSSA (Pennsylvania System of School
Assessment Test)

Worksheets that accompany text readings
o These will be checked throughout unit to monitor student progress and
understanding
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Unit: Cells and Cell Processes

Lab Reports/Lab Activities
o Labs will be used to assess for understanding the nature of science
o Lab analysis questions, graphs, and conclusions will be collected for each major
lab conducted. At least one lab per week will be conducted so that students can
acquire content knowledge and to develop 21st century skills related to
collaboration and communication
References
This we believe: Keys to educating young adolescents (2010). Westerville: Ohio: National
Middle School Association.
National Science Education Standards (1996). Washington, D. C.: National Academies Press.
NSTA position statement: Liability of scienceeducators for laboratory safety (n.d.). Retrieved
from http://www.nsta.org/about/positions/liability.aspx
Steinberg, L. (2005). Cognitive and affective development in adolescence. Trends in Cognitive
Sciences 9(2): 69-74.
Adapted from Unit Plan at http://edtech.tennessee.edu/~bobannon/unit_plans.html
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