I.   Grade/Course Title: 7th Grade Science

 

     

      b. Quarter: Two

 

II. Unit #3: Cells     Unit Length 6 weeks

                                                            

      a. Unit Introduction: During this unit students will discover that cells are the basic building blocks of life and each cell carries out life processes utilizing some common structures. These structures perform specific functions within the cell and function together to support life. Furthermore, cells come in many shapes and sizes and that cells have many different functions. Different types of cells have different organelles depending on the complexity of the cell. That all cells contain chromosomes that carry information needed to control the activities of the cell, to make new cells and new organisms. In addition, these cells reproduce through either mitosis or meiosis. These two different types of cell division have some similarities and differences depending on the type of cell that is dividing.

 

      b. Standards for Unit #3

 

·       C15. Describe the basic structures of an animal cell, including nucleus, cytoplasm, mitochondria and cell membrane, and how they function to support life.

·       C25. Explain the similarities and differences in cell division in somatic and germ cells.

·       CINQ6. Use appropriate tools and techniques to make observations and gather data.

         CT State Grade Level Expectations (Draft)

GRADE-LEVEL CONCEPT 1:  u All organisms are composed of one or more cells; each cell carries on life-sustaining functions.

GRADE-LEVEL EXPECTATIONS:

1.       Living things have characteristics that distinguish them from nonliving things.  Living things use energy, respond to their environment, grow and develop, produce waste and reproduce.

2.       Organisms are made of tiny cells that perform the basic life functions and keep the organism alive.  Many organisms (for example yeast, algae) are single-celled and many organisms (for example plants, fungi and animals) are made of millions of cells that work in coordination.

3.       All cells come from other cells and they hold the genetic information needed for cell division and growth.  When a body cell reaches a certain size, it divides into two cells, each of which contains identical genetic information.  This cell division process is called mitosis.

4.       The cell is filled with a fluid called cytoplasm; cells contain discrete membrane-enclosed structures called organelles. Each of the organelles performs a specific cellular function and it can be identified by its shape.

§       The nucleus contains the genetic materials (chromosomes), and it directs the cell activities, growth and division.

§       The mitochondrion contains enzymes that break down sugars and release chemical energy. One cell can contain hundreds of mitochondria.

§       The entire cell is surrounded by the plasma membrane which controls the flow of materials into and out of the cell. 

GRADE-LEVEL CONCEPT 1: u Heredity is the passage of genetic information from one generation to another.

GRADE-LEVEL EXPECTATIONS:

1.    Living organisms must reproduce to continue the existence of their species.   Through reproduction new individuals which resemble their parents are formed.  All the organisms alive today arose from preexisting organisms.

2.    All the cells in a multicellular organism result from a single fertilized egg cell, through a process of continuous cell divisions (mitosis).  Instructions for how an organism develops are stored in DNA molecules which are part of the chromosomes inside the cell nucleus.

3.    The chromosomes occur in matching pairs, and each cell in a multicellular organism contains the number of chromosomes that are typical of that species.  For example, cells in human beings contain 23 pairs of chromosomes; 46 in all.

4.    Organisms grow by increasing the number of body cells. During mitosis, a body cell first duplicates the chromosomes and then divides into two daughter cells, each one with a complete set of chromosomes. 

5.    Most multicellular organisms reproduce by sexual reproduction, in which new cells are produced by the combination of two germ cells (gametes).  The cell division that produces the germ cells is called meiosis.  During meiosis, matching chromosomes in each pair separate from each other so that each germ cell contains only half of the chromosomes of the original cell.

6.     Meiosis and gamete formation takes place in the reproductive organs; testes in males produce the sperm and ovaries in females produce the eggs.

 

      c. Essential Questions:

1. How do cells carry out life processes?

2. What is cell division?

3. Are there different types of cell division?

4. What are chromosomes?

5. What cell structures are vital for a cell to have?

6. What is mitosis and meiosis?

7. What is the difference between somatic and germ cells?

 

 

      d. Essential Content/Concepts:

1. Cells are the basic building blocks all living things.

2. Cells have organelles that carry out life processes

3. Cells have a cell membrane; some cells have a cell wall.

4. Different types of cells have different organelles.

5. All cells have chromosomes that control the activities of the cell.

6. Cell division takes place in all cells.

7. Cell division varies with different cells.

 

 

e. Essential Skills:

1. To be able to use a microscope.

2. Compare and contrast cell structures

3. Compare and contrast the cell division in somatic and germ cells.

 

 

f. Vocabulary –

Organelle, cell membrane, nucleus, cytoplasm, mitochondria, microscope, cell division, somatic cell, germ cell, chromosomes, cell theory, diffusion, osmosis, mitosis, meiosis, asexual reproduction, sexual reproduction, unicellular, multi-cellular

 

g. Science Misconceptions

1. That all cells do not have the same basic structures.

2. That cells are not three dimensional.           

3. That cell size is the same for all cells.

4. That more complex organisms have more chromosomes.  

      

Activities:

       Labs

      Microscope Lab with Elodea leaf and cheek cells

    1. compare and contrast cells
    2. diffusion with Elodea (http://biology.arizona.edu/sciconn/lessons/mccandless/elodea.html)

      Diffusion with an Egg

      Observation of Protozoa

      Frey “Exploring Cell Processes, Cell Biology Lab Kit”

      Projects

Cell Mobile

Build a Three Dimensional Cell

Edible Cells

Poster project comparing different types of cells

http://www.kathimitchell.com/cells.html

 

Research

 Bacteria found on or in the body.

 Smallest living organism

Write a Biography of a cell

 

Reading for Information

Stem Cells to any Cell

A Fix for Injured Knees

 

IV. Significant Tasks (ST) Cell Flash Cards

      a. Significant Task Introduction: This task gives students the opportunity to determine the value of using flash cards, self-examination and peer examination in learning vocabulary and factual information. It also incorporates hands-on materials with the visual appeal and support second many language learners need to become actively engaged in acquiring language. The language component builds on students’ knowledge of English syntax to reconstruct scrambled sentences containing key information and vocabulary for science. This lesson should work for the benefit of both native and non-native speakers of English.

 

 

      b. Length/Timing: 4-5 class periods

 

      c. Essential Questions: What are the parts of the cell?

 

      d. Assessment Tools (AT): Notebooks, projects, assessments, and labs

     

 

UNIT RESOURCES:

            Readings, Texts, Materials, Videos

 

Suggested Science Fair Topics

 

Example Assessment Questions

 

  1. The basic unit of all living things is the _____.

a. nucleus  b. cell    c. organ    d. chromosome

 

  1. What do all cells have in common?

a. They carry out life processes    b. They take part in fertilization

c. They reproduce sexually    d. They are unable to reproduce

 

  1. Variation in a new generation of organisms is the result of
  1. sexual reproduction involving one parent
  2. sexual reproduction involving two parents
  3. asexual reproduction involving one parent
  4. asexual reproduction involving two parents

 

4. The main parts of the cell are the cell membrane, the nucleus, and the _____.

a. plasma  b. cytoplasm  c. mitochondria  d. ribosomes

 

5. When a cell divides, each chromosome makes a copy that is

a. identical to the original

b. slightly different from the original

c. very different from the original

d. a mutation of the original

 

 

 

 

 

6. Mitosis is a process of cell division which results in the production of two daughter cells from a single parent cell. The daughter cells are identical to one another and to the original parent cell. Place the following stages in the correct order, label the stages 1-4.

_____Anaphase: The centromeres divide. Sister chromatids separate and move toward the corresponding poles.

_____
Metaphase: The chromosomes align at the equitorial plate and are held in place by microtubules attached to the mitotic spindle and to part of the centromere.

 ______  Prophase: The chromatin, diffuse in interphase, condenses into chromosomes. Each chromosome has duplicated and now consists of two sister chromatids. At the end of prophase, the nuclear envelope breaks down into vesicles

_______Telophase: Daughter chromosomes arrive at the poles and the microtubules disappear. The condensed chromatin expands and the nuclear envelope reappears.

_______Cytokinesis: The cytoplasm divides, the cell membrane pinches inward ultimately producing two daughter cells.

 

  1. Describe three ways in which plant cells differ from animal cells.

 

 

 

  1. A certain virus attacks the mitochondria in cells. What would happen to a cell if all of its mitochondria were destroyed?