Cell Structure, Mitosis and Meiosis

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Lesson Plan
 

Grade Level: 9-12 Grade
Title: Cell Structure, Mitosis, Meiosis  & DNA

Sunshine State Standards:

SC.F.1.4 The student describes patterns of structure and function in living things.
SC.H.1.4 The student uses the scientific processes and habits of mind to solve problems.
SC.H.2.4 The student understands that most natural events occur in comprehensible, consistent patterns.

Unit: Biology of the Cell, Genetics

Rationale:

It is important that students know that all living organisms are composed of cells, which is the beginning of life.  We will focus on eukaryotic cells, classifying them into plant and animal cells. Students should know the parts of eukaryotic cells to understand and assess the importance of reproduction and photosynthesis.

Goals Objective:

9th – 12th grade science students will identify the basic parts of plant and animal cells using the chart in their book and pictures/slides to distinguish their differences.  Each student will be able to label plant and animal cells with 100% accuracy.  Students will also be able to understand the importance of DNA, Mitosis and Meiosis, and how they are involved in the reproduction process.

Content (Outline):

1. Eukaryotic Cell – Literally "true nucleus".  The term applies to all protists, plants, animals, and fungi. Eukaryotic cells have internal membranes that partition them into regions for different functions, such as mitochondria, plastids, the ER, Golgi apparatus, etc. They also possess a cytoskeleton that helps them control their shape.
2. Animal Cell- contain parts that are listed on chart below.
3. Plant Cell- contain parts that are listed on the chart below.
4. Meiosis- (my-oh’sis) Process in which a 2n cell undergoes two successive nuclear divisions (meiosis I and meiosis II), potentially producing four n nuclei; leads to the formation of gametes in animals and spores in plants; division of cells during sexual reproduction.
5. Mitosis-  (my-toh’sis) Division of the cell nucleus, resulting in two daughter nuclei, each with the same number of chromosomes as parent nucleus. Mitosis consists of four phases: prophase, metaphase, anaphase, and telophase.  Cytokinesis (division of the cytoplasm to form two separate cells) usually overlaps the telophase stage. This process is the division of body (somatic) cells during reproduction.
6. DNA- Deoxyribonucleic acid. The genetic material of all organisms; composed of two complementary chains of nucleotides wound in a double helix. Chromosomes contain the genetic information that dictates what characteristics the daughter cells will possess.  It is useful to visualize a chromosome as a continuous strand of DNA.  Arrayed along the DNA strand are the genes, specific regions whose sequences carry the genetic code for making specific proteins.
 

Procedures:

Ø Anticipatory Set:
By a show of hands, who knows the difference between plant and animal cells?  Who can explain the difference between Mitosis and Meiosis? What is the purpose of DNA in the nucleus?

Ø Objective:
Tell the students that today’s lesson is to help them understand the contents of plant and animal cells. They will have basic knowledge regarding phases of Mitosis and Meiosis, and what an important role DNA plays in the reproduction of living things.

Ø Input:
Show plant and animal cell transparencies.  Explain that both types, although similar, contain certain different parts.  Show the phases of Mitosis and Meiosis using visual aids.  Show the DNA phases and explain how each step is important in reproduction.

Ø Model:
 

  Animal Plant
Cell wall Absent Present (cellulose)
Cell membrane Present Present
Flagella May be present Absent except in sperm of a few species
Endoplasmic reticulum Usually present Usually present
Ribosomes Present Present
Microtubules Present Present
Centrioles Present Absent
Golgi apparatus Present Present
Nucleus Present Present
Mitochondria Present Present
Chloroplasts Absent Present
Chromosomes Multiple; DNA-protein complex Multiple; DNA-protein complex
Lysosomes Usually present Present as "spherosomes"
Vacuoles Absent or small Usually a large single vacuole

Eukaryotic Cells








Mitosis


 
 

Meiosis

Major differences between mitosis and meiosis.

1. Number of cell divisions and products.
        mitosis - one cell division resulting in two daughter cells
        meiosis - two cell divisions resulting in four products of meiosis
 

2. Ploidy (# chromosome sets) per nucleus.
        mitosis - 2N to 2N
        meiosis - 2N to N to N

3. Synapsis of homologous chromosomes.
        mitosis - no pairing
        meiosis - pairing at zygotene of prophase I

4. Exchange of genetic material between synapsed homologous chromosomes.
        mitosis - does not occur
        meiosis - occurs at pachytene of prophase I (first visible at diplotene)

5. Timing of division of centromeres.
        mitosis - occurs at anaphase
        meiosis - occurs at anaphase II but not at anaphase I

6. Genetic variation.
        mitosis - conservative process; does not lead to genetic variation
        meiosis -  leads to increased genetic variation following recombination (crossing-over)
 
 

DNA

Ø Check for Understanding:

Ask students: Do plant cells contain centrioles, and what significant role do they play within the cell? Do animal cells contain chloroplasts? Which type of cell has a cell wall? What three parts of a plant cell are not parts of an animal cell? Is Mitosis and Meiosis the same thing?  How are they different?  Who knows the phases of mitosis?   What are chromosomes and what part do they play within the cell?  What are amino acids and why are they significant in a DNA strand?  Why is the understanding of chemistry an important part of biology?

Ø Guided Practice:

Tell students that the list of plant and animal cells shows the contents of each cell. Plant and animal cells have many of the same features, called organelles. These organelles are the basis of cell functions. However, plant cells have three major organelles of which animal cells do not, chloroplasts (carry chlorophyll), a cell wall (cellulose), and a large central vacuole (storage).
Mitosis is the process for cell division for body cell reproduction whereas Meiosis is the process of cell division for sexual reproduction. All cells contain DNA, prokaryotic and eukaryotic, as well as viruses. The process of translation and transcription are characteristics of DNA.

Ó Use diagram of cell to identify and label both types of cells.
Ó Review cell organelles on overhead projector.
Ó Use diagram of mitosis and meiosis to understand how cells divide and create daughter cells.
Ó Study the process of DNA and its significance within the cell.
Ó Create model of mitosis and DNA strand.
 

Ø Independent Practice:

Students are to name and select the correct organelle magnets placing them on the proper cell (animal or plant) on the board. Give students enough time to complete this task.  Worksheets on mitosis, meiosis, and DNA structure will be distributed to each student to test for knowledge and comprehension of cell division and reproduction.
 

Materials & Resources:

Plant and animal cell worksheet, Mitosis & Meiosis worksheet, DNA diagram and worksheet, transparencies, organelle magnets.
Biology textbooks: Raven Johnson 5e, Holt.
http://www.ultranet.com/~jkimball/BiologyPages/A/AnimalCells.html
http://mindquest.net/biology/cell-biology/cell-biology.html
http://esg-www.mit.edu:8001/esgbio/cb/org/organelles.html
http://www.dna.com
 

Questions:

 (3) Low Level:
1. Knowledge- List the organelles of an eukaryotic cell.
2. Comprehension- Determine what organelles belong to the plant and animal cell.
3. Application- Construct a brief diagram of the phases of meiosis.
(3) High Level:
4. Analysis-   Relate meiosis to mitosis and distinguish the similarities and differences.
5. Synthesis- How would you create your own diagram of DNA?
6. Evaluation- Assess the process of cell division and reproduction.
 

Evaluation:

After the review of eukaryotic cells, the students will be able to identify and name the organelles of plant and animal cells correctly.  Each student will have a basic knowledge and comprehension of cell division and reproduction through their study of mitosis and meiosis. Students will have an understanding of DNA within eukaryotic cells. They will create a model of a DNA strand and assess how it plays a role in reproduction.
 
 

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