7.4.1.2 Cells II

Grade: 
7
Subject:
Science
Strand:
Life Science
Substrand:
Structure and Function in Living Systems
Standard 7.4.1.2

All living organisms are composed of one or more cells which carry on the many functions needed to sustain life.

Benchmark: 7.4.1.2.1 Functions of Cells

Recognize that cells carry out life functions, and that these functions are carried out in a similar way in all organisms, including animals, plants, fungi, bacteria and protists.

Benchmark: 7.4.1.2.2 Cell Division for Growth

Recognize that cells repeatedly divide to make more cells for growth and repair.

Benchmark: 7.4.1.2.3 Plants vs. Animal Cells

Use the presence of the cell wall and chloroplasts to distinguish between plant and animal cells.

For example: Compare microscopic views of plant cells and animal cells.

Overview

Standard in Lay Terms 

Living things are composed of cells which are responsible for life functions.

Big Ideas and Essential Understandings 

Big Idea:

Cells are the building blocks of life.   The focus of study should be on the idea that basic functions of organisms are carried out in cells.  These functions include growth and repair, obtaining and using energy, transport of materials.  Cells of plants and animals can be distinguished by the presence of  a  cell wall and chloroplasts in plant cells.

Benchmark Cluster 

MN Standard Benchmarks

7.4.1.2.1

Recognize that cells carry out life functions, and that these functions are carried out in a similar way in all organisms, including animals, plants, fungi, bacteria and protists.

7.4.1.2.2

Recognize that cells repeatedly divide to make more cells for growth and repair.

7.4.1.2.3

Use the presence of the cell wall and chloroplasts to distinguish between plant and animal cells.

For example: Compare microscopic views of plant cells and animal cells.

THE ESSENTIALS:

The cartoon, from this site, can be download and used free of charge by individual teachers/educators.

Correlations 
  • 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

  • AAAS Atlas:

  • Benchmarks of Science Literacy

Grade 7

The Living Environment: Cells

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.

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

Frameworks 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 (i.e. connections with Math, Social Studies or Language Arts Standards): cell division can linked to mathematics through cell division. 

Misconceptions

Student Misconceptions 

7.4.1.2.1 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). [1]

[1] 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.

Vignette

"Good afternoon and welcome to the nucleus. Today we are taking a tour of the cell's control center with our good friend Mike Tokondria and Ronald Ribosome," began Geoffe. Geoffe had volunteered to be the talent for this part of the podcast assigned by Ms. D.

"Mike, what is that structure over there? It kind of looks like tube socks that my brother Steve has in his drawer."

"Well, Mr. Golgi, those are chromosomes. They are where the genes that control the cell are found. Every cell in a person's body has forty six of them."

"Mike, how can every cell have forty six of them, inside of the nucleus, when the nucleus is inside the cell and the cells are inside the body?" asked Ronald. His real name was Reggie, but he kind of like Ronald, anyway.

"Ronald, they must be pretty small to fit inside the nucleus and then fit inside the cell and then fit lots of them into the body." Mike replied. Mike was really Sidney, but Mike Tokondria fit him well. He had lots of energy going on......always.

Ms. D had assigned the students the podcast, "Interview with an Organelle" a couple days before. The past three days had seen the group gathering information about the cellular parts, writing scripts, rehearsing and learning how to run the software that would record the podcast.

With the help of the media center/technology person in the building, she had come up with the idea for the podcast. Students thought it would be cool to get their information on the web, so that other 7th graders could learn about organelles.

Many of the students had created movies on home computers, so instruction on editing podcasts went smoothly. Some had even used programs similar to this in recording music at home. Ms. D, found the software to be simple enough to use and with the media center instructor's help, she found it more like 'cut and paste' in word processing than anything.

The days prior to production were full of script writing and rehearsal. The podcast had to be between ninety and one hundred twenty seconds, so stopwatches and cell phone timers were out in abundance. Ms. D encouraged them to rehearse and rehearse so it didn't sound like they were reading, rather having a conversation.

Production went well. The students recorded mutliple takes for each segment: the 'catchy grabber', 'the introduction to who and where' the podcast was being produced, the 'content' and the 'commentary' about the importance of the cell part to the survival of the cell.

Rubrics and checklists are important to Ms. D. The rubric she provided helped the students write the script and make sure they had all the necessary information in the podcast. It also address technical issues like dead air and acceptable volume levels.

With the rehearsal, a useful tool in the rubric, a well written script, the students ran through production in a day. Even with the multiple takes for each segment, it was easy to go back and decide which was the best.

A quick click of the mouse and Ms. D had the podcasts ready for internet broadcast. She placed the files on her web page and threw them out on the web. Once the podcasts were available to the public, she sent emails home through the school grading application to let parents know where and how to listen to Mike, Ronald and Mr. Golgi.

Resources

Instructional Notes 

Instructional suggestions/options:

  • students build diorama of cell parts
  • coloring pages of plant and animal cells with organelles
  • use of digital images to measure cell volumes, size of cell parts
  • edible cell - jello cytoplasm, students provide the other parts
  • using clear, plastic drop cloths, build a 'walk in' model of a cell with hanging cell parts
  • make a flip book of cell division with post-it notes

Selected activities:

  • Lab using microscopes looking at single celled organisms. examples Volvox, paramecium, euglena, amoeba.  7.4.1.1.1.
  • study of onion root tip (stained vs. fresh) to quantify cells in the middle of division and create a pie chart that demonstrates length of time in demonstrating growth and division of cells, provide digital images of cells as well. 7.4.1.2.2.
  • using elodea or some other plant to observe cytoplasm streaming and movement of chloroplasts  7.4.1.2.2
  • plant cell vs. animal cells microscope comparison
  • slices of cork  7.4.1.2.3
  • cheek cells as animal cells  7.4.1.2.3
  • onion, potato, elodea as plants  7.4.1.2.3
  • study the growth of bread mold 7.4.1.2.3
  • study the growth of bacterial colonies on a plate of agar  7.4.1.2.3
Instructional Resources 

Additional resources or links:

 Cellular Process: Reproduction 

New Vocabulary 

Vocabulary/Glossary:                                  

  • cell  basic unit of all forms of life.
  • organelle  tiny sub cellular structure
  • cell theory  fundamental concepts 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
  • cell membrane  thin flexible barrier that surrounds all cells; regulates what enters and leaves the cell
  • nucleus   the center of an an atom which contains the protons and neutrons in cells, structure that contains the cells genetic material
  • chromosomes  threadlike structures within the nucleus that contains genetic information that is passed from one generation to the next.
  • cytoplasm fluid portion of the cell outside the nucleus
  • endoplasmic reticulum  internal membrane system found in eukaryotic cells; place where lipid components of the cell membrane are assembled.
  • ribosome cell organelle consisting of RNA and protein found throughout the cytoplasm in a cell; the site of protein synthesis
  • mitochondrion  rod shaped structure that is referred to as the powerhouse of a cell
  • vacuole  cell organelle that stores materials such as water, salts, proteins, and other materials.
  • chloroplast  large irregular shaped structure that contains the green pigment chlorophyll food making site in green plants.
  • diffusion process by which particles tend to move from an area where they are more concentrated to an area where they are less concentrated
  • osmosis  diffusion of water through a selectively permeable membrane
  • cell division is the process by which a parent cell divides into two or more daughter cells.
  • mitosis  part of eukaryotic cell division during which the cell nucleus divides
  • tissue  group of similar cells that perform a particular function
  • 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
  • organism  an individual made up of organ systems
Technology Connections 

Use of digital imaging software to highlight cell structures

Video examples of cell division Cell division

Create an audio or video podcast about a cell part

Internet connections if possible to help students look up cell division

Cameras/flip videos for students to record clips of their models.

microscopes for seeing the various stages of cell division

Hardware cameras that connect to microscopes to show students what chloroplasts look like and how plant cells are different from animal cells.

Cross Curricular Connections 

Work with art teacher to help students make scientific illustrations that convey information to the observer.

Assessment

Students:                                

What is TRUE about the size and shape of cells?

A.  All cells are the same size and shape.

B.  All cells are the same size, but not all cells are the same shape.

C.  All cells are the same shape, but not all cells are the same size.

D.   Different cells can have both different sizes and different shapes.

Which of the following parts of an animal's body are made of cells?

A.  The skin, but not the lungs

B.  The lungs, but not the skin

C   Both the skin and lungs

D.  Neither the lungs nor the skin

Using a Venn Diagram with plant and animal cell parts as the topic. The intersection of the circles is structures you find in both types of cells.

Using the SmartBoard have students model cell division with chromosomes to move and manipulate.

Using students as representatives of energy flow, have them demonstrate how energy flows through a system starting with a plant cell and ending with an animal cell.

Have students model cell division with themselves as chromosomes.

Summative Assessment

Have students tell/draw/cartoon the story of a cell's life and death.

Have students model cell division using pipe cleaners/pop it beads as chromosomes. They must demonstrate the various check points.

Students write an essay that explains the reason of cell size.

The teacher will have microscopes set up at lab stations around the room. Students will travel from scope to scope, identifying the stage of cell division.

Teachers:

Questions could be used as self-reflection or in professional development sessions.

Are we teaching for understanding or are we just having students memorize parts and steps?

Are we making sure students understand that all organisms including fungi, bacteria and protist carry out life functions?

What technology, both digital & non-digital is availabe to help students understand and visualize cells and cell processes?

Administrators:

If observing a lesson on this standard what might they expect to see.

Students using microscopes or building models of cells. 

Students using the internet to study cell parts with cells alive

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.

Creating models or diorama's allows at risk students to show true abilities without concentrating on the written word to show their understanding of concepts.

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.

Hands-on science learning promotes language connections

The same type of teaching and learning experiences do not work equally effectively for all cultural groups.

Students should be instructed to create models and label parts in duel languages. 

Extending the Learning 

G/T                   

  • 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 

Multicultural science education.  Official NSTA Position Statement.

This site hosts a English to Ojibwe and Ojibwe to English dictionary that may be used to look up meanings to vocabulary words.

Science education should include the use of culturally relevant content.  Atwater (1995a-c) and Banks(1987,1988) 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 should be given opportunities to do science rather than read about it.  Doing science includes reasoning about science.  This kind of science emphasizes the active role of the learner in constructing knowledge. 

Science instruction should not be isolated from the rest of the students' lives.  The contextualization of tasks can make a difference in performance.  Many science experiences are those of a special world, confusing, often couterintuitive and counter to daily experiences.  When students can participate in and observe science in the ordinary world in which they live, they are more likely to learn as well as come to appreciate science as a way of knowing.  When this can be embedded in a cultural context the possibilities for new understanding and connections become even stronger. 

Again projects should be constructed and labeled in duel language.

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.

The ability to create models allows special education students to create models that reflect their abilities. 

Parents/Admin

Parents 
  • Parents may be asked to supply household items for students models.
  • Parents may help students study terms of the cell.