Title: Mitosis

Author: Joanna Borgensztajn

Target group

A Student of the 8th grade of elementary school.

Core curriculum

General requirements

I. Knowledge of biological diversity and basic biological phenomena and processes. Student:

2 ) explains biological phenomena and processes occurring in selected organisms and in the environment;

Specific requirements

V. Genetics. Student:

4 ) shows the biological significance of mitosis and meiosis, distinguishes between haploid and diploid cells;

Lesson aim

Students discuss the process of mitosis and present its biological significance.

Criteria for success

• discuss the course of mitotic cell division;

• explain the importance of mitosis;

• determine the number of chromosomes in a cell that results from a mitotic division (knowing the number of chromosomes in the parent cell).

Key competences

• communicating in the mother tongue;

• communicating in a foreign language;

• Mathematical competence and basic competences in science and technology; 

• digital competence;

• learning to learn;

• Social and civic competences.

Methods/forms of work:

Mini‑lecture, work with film, didactic discussion, didactic game, subject exercises.

Individual work, work in pairs, work in groups.

Teaching measures:

• abstract;

• tablets/computers;

• interactive whiteboard or traditional blackboard;

• A4 pages;

• scissors.

Lesson phases

Introduction

1. The teacher determines the purpose of the lesson and informs the students about its planned course. Presents the criteria for success.

2. The teacher gives the topic of the lesson, the students write it in their notebooks.

Realization

1. The teacher defines the purpose of the lesson: „You will know the process of mitosis and its biological significance” and inform students about its planned course. Presents the criteria for success.

2. The teacher presents an ilustration entitled „Mitosis stages” and discusses the meiosis process for example:

(Interphase (G₂): In this substage, the cell prepares for nuclear division and a protein that makes microtubles for cell division is synthesized.

Prophase: The longest stage of mitosis. In this stage the chromosomes become visible and the centrioles separate and move to opposite poles of the cell.

Prometaphase: The nuclear envelope disintegrates and microtubules can attach to kinetochores. Chromosomes congress toward the metaphase plate of the cell.

Metaphase: In this stage the chromosomes line up across the center of the cell and become connected to the spindle fiber at their centromere.

Anaphase: In this stage the sister chromatids separate into individual chromosomes and are pulled apart.

Telophase & cytokinesis: Chromosomes decondense and are surrounded by a newly formed nuclear envelope. Cytokinesis typically coincides with and telophase.)

3. The teacher asks the students to draw on a sheet, several different geometric figures, representing chromosomes (eg circles, squares, triangles, stars). Each student passes his card to the persons on his desk. Pupils draw the appropriate figures on the pages provided in order to obtain the effect of duplicating the genetic material. In case of doubt, they agree on a correct solution between themselves. Then they cut the pages, resulting in a set of „chromosomes” on each half of it. For each of them they draw the appropriate figures once again.

4.The teacher recommends students to perform „Task 1”, „Task 2” and „Task 5”. The selected pupil's present the their work to the class. The teacher complements students' statements and corrects possible mistakes.

5. The teacher initiates a discussion on the biological significance of mitosis in the context of reproduction of single‑celled organisms and the development of multicellular organisms.

6. Students independently perform interactive exercises that improve the knowledge gained during the lesson.

Summary

Students ask questions, ask for additional explanations and complete their notes.

Homework

How many divisions occur in mitosis?

Consider the importance of mitosis in nature.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Mitosis

Cell division allows organisms to grow and develop, as well as reproduce, or in other words, increase the numbers. These are the basis for the survival of the species and the evolution of life. The division of eucaryotic cell consists of two stages. The first is the division of the cell nucleus. The second stage is the division of the cytoplasm and cell organelles contained in it.

Nuclear (eukaryotic) organisms are distinguished by two basic types of cell division. One leads to the production of cells with the same number of chromosomes and it's called mitosis. The effect of the second, meiosis, is the formation of cell with reduced by half haploid number in chromosomes.

During mitosis one mother cell produces two daughter genetically identical cells. One could say that the purpose of this division is to multiply the number of the same cells. In the case of unicellular organisms that have a nucleus, the result of mitosis is an increase in the number of individuals. In the case of multicellular organisms, the result of mitosis is their growth, which consists in increasing the number of cells in the body.

The frequency of mitotic divisions can differ at various periods of the organism's life and in various areas of the body. Usually, it is more intense in the early stages of development and is later slowed. Cells of some tissues divide intensively throughout entire life, e.g. human skin cells, meristem cells in plants.

Both diploid cells and haploid cells may undergo mitosis. As a result of the mitotic division of the diploid cell two diploid cells will be created, and the haploid cell will become two haploid cells.

• Diploid cells contain a double set of chromosomes, and haploid cells contains a single one.

• Prior to cell division, there is always a doubling of the amount of DNA in the cell nucleus.

• Mitosis is the division of the nucleus, thanks to which two daughter cells with identical genetic information are formed from one stem cell.

• Mitosis allows the growth and development of multicellular organisms and the reproduction of unicellular organisms.