7.4.1.1 Cells I

Grade: 
7
Subject:
Science
Strand:
Life Science
Substrand:
Structure and Function in Living Systems
Standard 7.4.1.1

Tissues, organs and organ systems are composed of cells and function to serve the needs of all cells for food, air and waste removal.

Benchmark: 7.4.1.1.1 Tissues & Organs

Recognize that all cells do not look alike and that specialized cells in multicellular organisms are organized into tissues and organs that perform specialized functions.

For example: Nerve cells and skin cells do not look the same because they are part of different organs and have different functions.

Benchmark: 7.4.1.1.2 Organ Interactions

Describe how the organs in the respiratory, circulatory, digestive, nervous, skin and urinary systems interact to serve the needs of vertebrate organisms.

Overview

Standard in Lay Terms 

MN Standard in Lay Terms

Living systems are organized into levels of increasing complexity of structure and function; starting with cells, then tissues, then organs, then organ systems and lastly organisms.  These function to provide food, air, and remove waste for the good of the cells.

Big Ideas and Essential Understandings 

Living systems, regardless of size, have common divisions of labor to help with life's processes.  In multicellular organisms, all cells are specialized, look different, and are organized into tissues and organs that also have specialized functions.  Vertebrate organisms benefit when all systems, especially the respiratory, circulatory, digestive, nervous, skin, and urinary/excretory systems, work together to maintain the whole organism.

 

©Gary Larson

 

Benchmark Cluster 

7.4.1.1.1

Recognize that all cells do not look alike and that specialized cells in multi-cellular organisms are organized into tissues and organs that perform specialized functions.

For example: Nerve cells and skin cells do not look the same because they are part of different organs have different functions.

7.4.1.1.2

Describe how the organs in the respiratory, circulatory, digestive, nervous, skin and urinary systems interact to serve the needs of vertebrate organisms.

Correlations 

Grade 7

Once they have some "magnification sense," students can use photomicrographs to extend their observations of cells, gradually concentrating on cells that make up internal body structures. The main interest of youngsters at this level is the human body, so they can begin with as many different kinds of body cells as possible-nerve, bone, muscle, skin-and then move on to examining cells in other animals and plants. This activity can show students that cells are the fundamental building blocks of their own bodies and of other living things as well. Also, once students see that tissue in other animals looks pretty much the same as tissue in humans, two important claims of science will be reinforced: the ubiquity of cells and the unity of nature.

Grade 8

By the end of the 8th grade, students should know that:

  • All living things are composed of cells, from just one to many millions, whose details usually are visible only through a microscope. 5C/M1a
  • Different body tissues and organs are made up of different kinds of cells. 5C/M1b
  • The cells in similar tissues and organs in other animals are similar to those in human beings but differ somewhat from cells found in plants. 5C/M1c
  • Cells repeatedly divide to make more cells for growth and repair. 5C/M2a
  • Various organs and tissues function to serve the needs of all cells for food, air, and waste removal. 5C/M2b
  • Within cells, many of the basic functions of organisms-such as extracting energy from food and getting rid of waste-are carried out. 5C/M3a
  • The way in which cells function is similar in all living organisms. 5C/M3b
  • About two thirds of the weight of cells is accounted for by water, which gives cells many of their properties. 5C/M4

NAEP (optional)

Framework for K-12 Science Education

All living things are made up of cells, which is the smallest unit that  can be said to be alive. An organism  may consist of one single cell (unicellular) or many different  numbers  and types of cells (multicellular). Unicellular organisms  (microorganisms), like multicellular organisms, need food, water,  a way to dispose of waste, and an environment in which they can live.


Within cells, special structures are responsible  for particular functions,  and the cell membrane  forms the boundary that  controls  what  enters and leaves the cell. In multicellular organisms, the body is a system of multiple  interacting  subsystems. These subsystems are groups  of cells that  work  together  to form tissues or organs  that  are specialized for particular body functions.  8LS1.A

Common Core Standards

(Language arts will be covered with student vocabulary.)

 

NSES Standards:

Life Science

Content Standard C
As a result of their activities in grade 7, all students should develop understanding of

1.     Structure and function in living systems

2.     Reproduction and heredity

3.     Regulation and behavior

4.     Populations and ecosystems

5.     Diversity and adaptations of organisms

 

Benchmarks for Science Literacy

NSDL Science Literacy Maps: The Living Environment: Cell Functions

 

Misconceptions

Student Misconceptions 

7.4.1.1.1 Preliminary research indicates that it may be easier for students to understand that the cell is the basic unit of structure (which they can observe) than that the cell is the basic unit of function (which has to be inferred from experiments).

Dreyfus, A., Jungwirth, E. (1989). The pupil and the living cell: A taxonomy of dysfunctional ideas about an abstract idea. Journal of Biological Education, 23, 49-55.

The four student misconceptions below are from the AAAS Project 2061 Science Assessment Website: Registration (free) required

 

  • Some living parts of organisms are not made of cells (AAAS Project 2061).                       
  • All cells are the same size and shape, i.e., there is a generic cell (AAAS Project 2061).       
  • Cells do not carry out essential life functions for the organism they are part of (AAAS Project 2061).     
  • Cells are not organized into the body structures of the organism they are part of (AAAS Project 2061)

Vignette

I think mine is still warm," said Jeremy as he held up the sheep eye.

"Gross!" shrieked Jazmyne as she turned away from the table and the dissecting pan containing the sheep eye.

Mrs. S had been to a butcher shop earlier in the day to obtain eyes from freshly killed sheep, pigs and cows for today's lesson. She had called the shop a few weeks ago to set up the amount and ensure the fact they would get fresh eyes. The lens in a fresh eye is transparent and easy to see through, whereas the lens will cloud and the impact of the lesson is lost when the students peel off the sclera and retina to get to the vitreous humor in the back of the eye.

This lesson is seen being taught during the introduction to the human body unit. Students have had a chance to look at pictures of various cell types and also preserved slides that are carefully labeled and identified for the seventh graders. They often have a hard time identifying the cell types when they are in situ and under the microscope. So, with some guidance and carefully preparing the class with images, the students can find the cell types under the microscopic lens. The eye is composed of epithelia, connective tissue, nervous tissue and muscle tissue and they all work in concert to make the eye work properly.

Mrs. S has had the students practice with scalpels on grapes. "You just want the blade of the scalpel to penetrate the skin of the grape, any thing deeper, could damage the underlying structures." To demonstrate this, she grips the blade of the scalpel with her thumb and forefinger, leaving a millimeter or two of the blade sticking out.

The students secured the eyes to the pans with t-pins and began the dissection.

By observing the optic nerve, which enters the posterior of the eye, student can see what a nerve looks like. The fibers of the groups of neurons are fibrous and can be teased apart, depending on how much was left by the butcher. Mrs. S had asked that muscles remain intact and for the most part they were just that. Again, the muscle bundles can be teased apart to see the fibrous nature of muscles. A sharp scalpel is necessary to penetrate the tough collagen shell of the sclera. Several repeated strokes with the technique shown by Mrs. S would be used to get through to the retina.

If the students dissect carefully, the sclera can be peeled back to reveal the retinal layer of neurons. Once the retina is removed, the students can peer through the eye from the rear. This view is surprising to the students and best left to discovery. The fresh eyes help with this view. It is best not to have a cloudy lens.

The students continue to dissect. Mrs. S had asked them to make observations as the dissection continues. Diagramming and describing the various tissues, students conclude the lesson by writing summary statements about the relationship between the structure of cells and the how they work together to create tissues and organs like the mammalian eye.

Resources

Instructional Notes 

Selected Labs and Activities

  • Get Inside a Cell! Investigate how form and function are related in cells through scientific illustration. How can illustration show us the relationship between form and function in a cell?  7.4.1.1.1.
  • Research cell types and use technology to create visuals to display in room  7.4.1.1.1.1
  • You and Your Skin 7.4.1.1.1.1 This resource provides an introduction to the basic structure of the skin, information about how the skin protects us, and some information on how to care for the skin. There are four main sections to the resource: Function, Anatomy, Protection, and Care. When you click on one of the main sections, you'll be taken to an enlarged view of that section, which contains several subsections represented by the highlighted ring around the circle. Roll your mouse over the ring to see the subsections. To go to one of the subsections, simply click on it. To move from one of the main sections to another, simply click on one of the red arrows found by the ring.
  • Heart dissection - study the flow of blood through the heart, how the heart is assembled and interacts with other parts of the body   7.4.1.1.2
  • Tissues of Life 7.4.1.1.2 Study the four basic cell types that make up the human body on this web adventure from the Science Museum of Minnesota.
  • Lung dissection - how does air flow through the lungs. what are the tissues that make up the heart.  7.4.1.1.2
  • Inch of Skin 7.4.1.1.12 Explore the various nerve receptors in the skin of the human hand
  • Assemble a skeleton or skeleton model - find one, or make one from a turkey, chicken or deer  7.4.1.1.2
  • Instructional suggestions/options;
  • Using a 3D model of the human body study the anatomy and function of each organ, sort them according to body system  7.4.1.1.2
  • Create paper model cells that can be put together to build the cell, tissue, organ concept.   7.4.1.1.1.

 

New Vocabulary 

Vocabulary/Glossary

  • Cell: basic unit of all forms of life.
  • Cell division: is the process by which a parent cell divides into two or more daughter cells.
  • Cell membrane: thin flexible barrier that surrounds all cells; regulates what enters and leaves the cell.
  • Cell theory: fundamental concept of biology that states that all living things are composed of cells, that cells are the basic units of structure and function in living things, and that new cells are produced from existing cells.
  • Cell wall: strong supporting layer around the cell membrane in some cells.
  • Chloroplast: organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy.
  • Cytoplasm: fluid portion of the cell outside the nucleus.
  • Organ: group of tissues that work together to perform closely related functions.
  • Organ system: group of organs that work together to perform a specific function.
  • Organelle: tiny cell structure.
  • Organism: an individual made up of organ systems.
  • Nucleus: the center of an an atom which contains the protons and neutrons; in cells, structure that contains the cell's genetic material.
  • Respiration: process by which living organisms take in oxygen and use it to produce energy.
  • Tissue: group of similar cells that perform a particular function.
Technology Connections 
  • Survey of cell types using a webquest  Webquest
  • Interview a body-part video/flip cameras used to record a classmate being a body part.
  • Internet connections if possible to let students use technology to help learn.
  • Microscopes to look at cells, tissues, organs
  • Hardware cameras that connect to microscopes to take pictures of cells and display on the white board for students.
  • The Exploratorium's Cow Eyeball Dissection "How Does Your Eye Work?"
Cross Curricular Connections 

Art is a big part of science, students will need to draw and or recognize cells, tissues, organs, organ systems.

Assessment

Assessment of Students

Formative Assessment:

  • Given images of plant and animal cells, make decisions about what the differences are between the two cells.
  • Create a Venn Diagram that show similarities and differences between plant and animal cells.
  • Given a chunk of clay or playdough, a student will model the process of cell division.

 

Assessment of Teachers

  • How can you help students make connections between cells and life functions in all organisms?

Differentiation

Struggling Learners 

Struggling and At-Risk

  • Snow, D. (2003). Noteworthy perspectives: Classroom strategies for helping at-risk students (rev. ed.). Aurora, CO: Mid-continent Research for Education and Learning.
  • In 2002, McREL conducted a synthesis of recent research on instructional strategies to assist students who are low achieving or at risk of failure. From this synthesis of research, McREL identified six general classroom strategies that research indicates are particularly effective in helping struggling students achieve success.
  • Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.
  • Have students create posters of organ systems with pictures and organs labeled.
English Language Learners 
  • Herr, N. (2007). The sourcebook for teaching science. This page contains strategies to help teachers better attend to the needs of their ELL learners. These strategies are grouped according to the following learning tasks: listening, visualization, interpersonal communication, laboratory, demonstrations, reading and writing, instruction and vocabulary.
  • Have students create posters of organ systems with pictures and organs labeled in English and students native language.

 

Extending the Learning 
  • Teachers First is an educational support website that may help with G/T students
  • Cogito is another website that is available for G/T Students

 

Multi-Cultural 
  • Science education should include the use of culturally relevant content.  Atwater and Black (Ferguson, Robert. "If Multicultural Science Education Standards' Existed, What Would They Look Like?."Journal of Science Teacher Education. 19.6 (2008): 547-564. Print.) have proposed several ways to integrate culturally relevant content into the curriculum.  The value of using such approaches is that they can improve the conversation about beliefs in science and hone beliefs about science for all students.
  • Students must be encouraged to write as much as possible, both in their home language and in English.  Labeling the parts of the eye in labs such as the one in the vignette would allow multi-cultural students to practice english and their native language.
  • Have students create posters of organ systems with pictures and organs labeled in English and students native language.
  • Multicultural science education.  Official NSTA Position Statement.
  • Freelang.net hosts a English to Ojibwe and Ojibwe to English dictionary that may be used to look up meanings to vocabulary words.
Special Education 
  • Technologies for Special Needs Students: In their newsletter, "Tech Trek",  from the National Science Teachers Association, there are suggestions for using technology including voice recognition software
  • Hands on labs like the one in the vignette helps special ed students comprehend concepts better than straight book work.
  • Learning experiences should be as multi-sensory as possible and safe.  Such experiences have an added benefit too.  They are effective with all learners. 
  • Create posters of an organ system using pictures and labels.

Parents/Admin

Classroom Observation 

Administrators

  • Administration might see students using a microscope, drawing their observations. The science teacher may have recruited the art teacher to come and give a lesson on drawing.
  • Administration might facilitate the purchase of hearts and lungs from local meat markets/butcher shops so that students can dissect specimens of major organs.
  • Administration might see students scraping the inside of their cheek in search of a sample of cells to look at under the microscope to identify characteristics of an animal cell.
  • Students are practicing safety in their classroom, wearing goggles and using care with sharp instruments.

 

Parents

  • Quiz students about the parts of cells.
  • Ask students to explain about dissections that occur in class.