Mitosis and Meiosis - Nicole Morrow
Curriculum Expectations
D2.2 investigate the process of meiosis, using a microscope or similar instrument, or a computer simulation, and draw biological diagrams to help explain the main phases in the process
D3.1 explain the phases in the process of meiosis in terms of cell division, the movement of chromosomes, and crossing over of genetic material
D3.2 explain the concepts of DNA, genes, chromosomes, alleles, mitosis, and meiosis, and how they account for the transmission of hereditary characteristics according to Mendelian laws of inheritance
D3.4 describe some genetic disorders caused by chromosomal abnormalities (e.g., non-disjunction of chromosomes during meiosis) or other genetic mutations in terms of chromosomes affected, physical effects, and treatments
D3.1 explain the phases in the process of meiosis in terms of cell division, the movement of chromosomes, and crossing over of genetic material
D3.2 explain the concepts of DNA, genes, chromosomes, alleles, mitosis, and meiosis, and how they account for the transmission of hereditary characteristics according to Mendelian laws of inheritance
D3.4 describe some genetic disorders caused by chromosomal abnormalities (e.g., non-disjunction of chromosomes during meiosis) or other genetic mutations in terms of chromosomes affected, physical effects, and treatments
Learning Goals - Students will be able to:
1. Use the appropriate terminology to describe the process of mitosis and meiosis
2. Model the phases of mitosis and meiosis using pipe cleaners
3. Compare the process of mitosis and the process of meiosis
4. Illustrate and explain the stages of mitosis and meiosis using biological diagrams
5. Discuss the movement of chromosomes throughout the process of mitosis and meiosis
6. Explain the process of crossing over of genetic material
7. Investigate various genetic disorders caused by chromosomal abnormalities during meiosis
2. Model the phases of mitosis and meiosis using pipe cleaners
3. Compare the process of mitosis and the process of meiosis
4. Illustrate and explain the stages of mitosis and meiosis using biological diagrams
5. Discuss the movement of chromosomes throughout the process of mitosis and meiosis
6. Explain the process of crossing over of genetic material
7. Investigate various genetic disorders caused by chromosomal abnormalities during meiosis
Content:
Mitosis
The Cell Cycle
Cells reproduce through a continuous sequence of growth and division known as the cell cycle. The cell cycle consists of two main stages,
Mitosis has three main functions:
Mitosis and cell division occur in all somatic cells. New cells that are produced for growth or repair are identical to the previously existing cells. The instructions to form each new cells are stored in the nucleus of the cells. Chromosomes within the nucleus hold the genetic information needed to maintain the cell and to make new copies of the cell. Each chromosome is made up of two sister chromatids, which are held together by a centromere. Sister chromatids are genetic copies of each other.
The function of mitosis is to maintain the same number of chromosomes from cell to cell. During cell division, the parent cell divides to produce two new daughter cells. Mitosis ensures that each daughter cell contains the same number of chromosomes and the same genetic information as the parent cell.
Cells reproduce through a continuous sequence of growth and division known as the cell cycle. The cell cycle consists of two main stages,
- Growth stage (Interphase)
- Division stage
Mitosis has three main functions:
- Growth
- Repair
- Maintenance
Mitosis and cell division occur in all somatic cells. New cells that are produced for growth or repair are identical to the previously existing cells. The instructions to form each new cells are stored in the nucleus of the cells. Chromosomes within the nucleus hold the genetic information needed to maintain the cell and to make new copies of the cell. Each chromosome is made up of two sister chromatids, which are held together by a centromere. Sister chromatids are genetic copies of each other.
The function of mitosis is to maintain the same number of chromosomes from cell to cell. During cell division, the parent cell divides to produce two new daughter cells. Mitosis ensures that each daughter cell contains the same number of chromosomes and the same genetic information as the parent cell.
The Phases of Mitosis
Four phases of mitosis include:
Four phases of mitosis include:
- Prophase
- Metaphase
- Anaphase
- Telophase
Prophase
|
|
Metaphase
|
|
Anaphase
|
|
Telophase
|
|
Cytokinesis
|
|
Errors in Mitosis
Sometimes errors can occur during the process of mitosis including:
Sometimes errors can occur during the process of mitosis including:
- If there is a mutation caused by mutagens, toxic compounds, radiation or viruses, this mutation can be copied to the daughter cells and may cause a permanent error in the normal DNA molecule
- Certain genes act like switches to regulate the rate of mitosis. If these genes are altered by a mutation, the the rate of mitosis will be affected.
Meiosis
Production of Reproductive Cells
The zygote contains chromosomes from both parents, but it does not contain double the number of chromosomes found in a normal body cell. How is this possible? The answer lies in a process called meiosis. Meiosis is a special type of cell division that occurs only in reproductive organs. Meiosis produces reproductive cells called gametes. The gametes, either eggs or sperm, are haploid (n), which means they contain only one copy of each type of chromosome that the diploid (2n) parent cell contains.
Meiosis involves two sequences of phases:
Phases of Meiosis
Interphase
Prophase I
The zygote contains chromosomes from both parents, but it does not contain double the number of chromosomes found in a normal body cell. How is this possible? The answer lies in a process called meiosis. Meiosis is a special type of cell division that occurs only in reproductive organs. Meiosis produces reproductive cells called gametes. The gametes, either eggs or sperm, are haploid (n), which means they contain only one copy of each type of chromosome that the diploid (2n) parent cell contains.
Meiosis involves two sequences of phases:
- Meiosis I
- Meiosis II
Phases of Meiosis
Interphase
- Chromosomes replicate during interphase
- Before replication, the chromosomes are not condensed and are not easily visible
- After replication, each chromosome is made up of a pair of identical sister chromatids
- The chromatids are joined together by a centromere
Prophase I
- Similar chromosomes called homologous chromosomes pair to form homologous pairs
- The homologous pair, which is made up of four chromatids, is called a tetrad
- Each diploid cell has two copies of each chromosome, one copy of the chromosome pair was donated by the female gamete (egg), and the other copy was of the chromosome was donated by the male gamete (sperm)
- During the pairing process, crossing over of chromatids can occur, in which non-sister chromatids exchange genese which contributes greatly to genetic variation
Metaphase I
Anaphase I
Telophase I
Meiosis II
The phases of meiosis II are identical to mitosis:
Each cell beginning meiosis II is haploid but consists of replicated chromosomes (each consisting of two chromatids). At the end of meiosis II, the daughter cells are still haploid but each cell contains single unreplicated chromosomes. The daughter cells at the end of meiosis II are called gametes in animals and either gametes or spores in plants.
- A spindle fibre from one pole attaches to one pair of sister chromatids, and a spindle fibre from the opposite pole attaches to the other pair of sister chromatids in the tetrad
- The spindle fibres pull each tetrad to the equator of the celI and the chromosomes line up in their homologous pairs
- In each pair, one homologous chromosome is positioned on one side of the cell's equator, and the other homologous chromosome is positioned on the other side of the cell's equator
- The chromosomes are all positioned randomly so that some sister chromatids of maternal origin face one pole while other sister chromatids of maternal origin face the other pole of the cell
- This random positioning of tetrads along the cell's equator is called independent assortment
Anaphase I
- The homologous chromosomes separate and move to opposite poles of the cell
- They are pulled apart by the shortening of the spindle fibres
- The centromeres do not split and the sister chromatids are still held together
- Only one chromosome from each pair will move to each pole of the cell
Telophase I
- Homologous chromosomes begin to uncoil and the spindle fibres disappear
- The cytoplasm is divided
- The nuclear membrane forms around each group of homologous chromosomes, and two cells are formed
- Each chromosome already consists of two chromatids, a second chromosome replication does not take place
Meiosis II
The phases of meiosis II are identical to mitosis:
- Prophase II
- Metaphase II
- Anaphase II
- Telophase II
Each cell beginning meiosis II is haploid but consists of replicated chromosomes (each consisting of two chromatids). At the end of meiosis II, the daughter cells are still haploid but each cell contains single unreplicated chromosomes. The daughter cells at the end of meiosis II are called gametes in animals and either gametes or spores in plants.
Gamete Formation
The end result of meiosis is the production of gametes. This process, called gametogenesis, results in the production of sperm and eggs. The process of male gamete production in animals is called spermatogenesis. The process of female gamete production in animals is called oogenesis.
Spermatogenesis
Oogenesis
The end result of meiosis is the production of gametes. This process, called gametogenesis, results in the production of sperm and eggs. The process of male gamete production in animals is called spermatogenesis. The process of female gamete production in animals is called oogenesis.
Spermatogenesis
- Meiosis in mature males takes place in the testes, the male reproductive organs
- The production of sperm starts with a diploid germ cell called a spermatogonium
- This cell enlarges and undergoes meiosis I and meiosis II
- The final product is four haploid sperm cells
- Each sperm cell has the same number of chromosomes and the same amount of cytoplasm
Oogenesis
- In females, meiosis takes place in the ovaries, the female reproductive organs
- This process starts with a diploid germ cell called an oogonium.
- This cell enlarges and undergoes meiosis I and meiosis II
- At the end of meiosis I, the cytoplasm is not equally divided between the two daughter cells
- The cell that receives most of the cytoplasm is called the primary oocyte. The other cell is called a polar body and is not a viable sex cell
- As the primary oocyte undergoes meiosis II, the cytoplasm is again unequally divided
- Only one cell becomes an egg, or ovum, and contains most of the cytoplasm. The other cell, a polar body, is not a viable sex cell
Errors in Meiosis
The failure of chromosomes to separate properly, called nondisjunction, can occur during meiosis. This error results in the addition or deletion of one or more chromosomes from a gamete. Some disorders caused by nondisjunction include:
The failure of chromosomes to separate properly, called nondisjunction, can occur during meiosis. This error results in the addition or deletion of one or more chromosomes from a gamete. Some disorders caused by nondisjunction include:
- Down syndrome: Trisomic disorder where there is an extra chromosome number 21
- Turner syndrome: Monosomic disorder in which a female has a single X chromosome
- Klinefelter syndrome: Trisomic disorder in which a male carries an XXY condition.
Assessment Tools
Mitosis in Onion Root Tip Cells Lab
The objectives for of this lab exercise are:
The objectives for of this lab exercise are:
- Better understand the process and stages of mitosis.
- Prepare your own specimen of onion root in which you can visualize all of the stages of mitosis.
- Apply an analytical technique by which the relative length of each stage of mitosis can be estimated.
mitosis_in_onion_root_tip_lab.pdf | |
File Size: | 415 kb |
File Type: |
Mitosis and Meiosis Pipe Cleaner Activity
The objectives for this activity are:
The objectives for this activity are:
- Better understand the process and stages of mitosis and meiosis.
- Visualize the phases using pipe cleaners.
pipecleanermitosismeisosactivity.doc | |
File Size: | 54 kb |
File Type: | doc |
Mistakes in Meiosis
The objective for this online activity is:
Link: http://www.sumanasinc.com/webcontent/animations/content/mistakesmeiosis/mistakesmeiosis.html
The objective for this online activity is:
- Better understand the errors that can be made during Meiosis which cause specific disorders
Link: http://www.sumanasinc.com/webcontent/animations/content/mistakesmeiosis/mistakesmeiosis.html
Mitosis and Meiosis Quiz
The objective for this quiz is:
The objective for this quiz is:
- Use understanding of mitosis and meiosis to answer the multiple choice questions.
mitosismeiosisquiz.docx | |
File Size: | 260 kb |
File Type: | docx |
Videos: Lesson Hooks
Mitosis Vs. Meiosis Song
The following video goes over the phases of mitosis and meiosis using the beat to the popular song, "BEDROCK".
The following video goes over the phases of mitosis and meiosis using the beat to the popular song, "BEDROCK".
Mitosis Dance
Students from a school acted out the phases of mitosis through a dance. Students were able to act as the different parts of the cell that was undergoing cell division. This could possibly be used as an activity if the students are interested in making their own mitosis dance.
Students from a school acted out the phases of mitosis through a dance. Students were able to act as the different parts of the cell that was undergoing cell division. This could possibly be used as an activity if the students are interested in making their own mitosis dance.
Meiosis Square Dance
This is a short video that would be a silly introduction into the process of Meiosis.
This is a short video that would be a silly introduction into the process of Meiosis.
Videos: Resources
Cell Division Under Contrast Microscope
This video shows the process of mitosis underneath a contrast microscope which allows for the stages and parts of the cell to be clearly seen.
This video shows the process of mitosis underneath a contrast microscope which allows for the stages and parts of the cell to be clearly seen.
Phases of Mitosis
A detailed Khan Academy video describing the phases of mitosis. It is a little lengthy so would be a good resource to give to student to view on their own time.
A detailed Khan Academy video describing the phases of mitosis. It is a little lengthy so would be a good resource to give to student to view on their own time.
Mitosis
Short video describing the process of mitosis with interesting animations and clear descriptions.
Short video describing the process of mitosis with interesting animations and clear descriptions.
Phases of Meiosis
A detailed Khan Academy video describing the phases of meiosis. It is a little lengthy so would be a good resource to give to student to view on their own time.
A detailed Khan Academy video describing the phases of meiosis. It is a little lengthy so would be a good resource to give to student to view on their own time.
Meiosis
Short video describing the phases of meiosis with animations and descriptions.
Short video describing the phases of meiosis with animations and descriptions.
Glossary
asexual reproduction: the production of offspring from a single parent; offspring inherit genes of that parent only
autosomes: the chromosomes not involved in sex determination
centrioles: small protein bodies that are found in the cytoplasm of animal cells
centromere: the structure that holds the chromatids together
chromatin: the tangled fibrous complex of DNA and protein within a eukaryotic nucleus
crossing over: the exchange of genetic material between two homologous chromosomes
cytokinesis: the division of the cytoplasm
diploid: refers to twice the number of chromosomes in a gamete. Every cell body, with the exception of sex cells, contains a diploid chromosome number.
Down syndrome: a trisomic disorder in which a zygote receives three homologous chromosomes for chromosome pair number 21
gametes: sex cells that have a haploid chromosome number
gametogenesis: the formatioon of gametes (sex cells) in animals
haploid: refers to the number of chromosomes in a gamete
homologous chromosomes: paired chromosomes similar in shape, size, gene arrangement, and gene information
interphase: the time interval between nuclear divisions. During this phase, a cell increases in mass, roughly doubles the cytoplasmic components, and duplicates its chromosomes.
karotype chart: a picture of chromosomes arranged in homologous pairs
Klinefelter syndrome: a trisomic disorder in which a male carries an XXY condition.
meiosis: two-stage cell division in which the chromosome number of the parental cell is reduced by half. Meiosis is the process by which gametes are formed.
mitosis: a type of cell division in which a daughter cell receives the same number of chromosomes as the parent cell
monosomy: the condition where there is a single chromosome in place of a homologous pair
oocytes: immature eggs
ootid: an unfertilized ovum
polar bodies: cells that contain all the genetic information of a haploid ovum but lack sufficient cytoplasm to survive; formed during meiosis in females
sex chromosomes: the pair of chromosomes that have a role in the sex of an individual
sexual reproduction: the production of offspring from the union of two sex cells, one from each different parent. The genetic makeup of the offspring is different from that of either parent.
sister chromatids: a chromosome and its duplicate, attached to one another by a centromere. The pair remains attached until separated during mitosis.
spindle fibres: protein structures that guide chromosomes during cell division
synapsis: the pairing of homologous chromosomes
tetrad: a pair of homologous chromosomes each with two chromatids
trisomy: the condition where there are three homologous chromosomes in place of a homologous pair
Turner syndrome: a monosomic disorder in which a female has a single X chromosome
zygote: a cell resulting from the union of a male and female sex cell, until it divides and then is called an embryo
autosomes: the chromosomes not involved in sex determination
centrioles: small protein bodies that are found in the cytoplasm of animal cells
centromere: the structure that holds the chromatids together
chromatin: the tangled fibrous complex of DNA and protein within a eukaryotic nucleus
crossing over: the exchange of genetic material between two homologous chromosomes
cytokinesis: the division of the cytoplasm
diploid: refers to twice the number of chromosomes in a gamete. Every cell body, with the exception of sex cells, contains a diploid chromosome number.
Down syndrome: a trisomic disorder in which a zygote receives three homologous chromosomes for chromosome pair number 21
gametes: sex cells that have a haploid chromosome number
gametogenesis: the formatioon of gametes (sex cells) in animals
haploid: refers to the number of chromosomes in a gamete
homologous chromosomes: paired chromosomes similar in shape, size, gene arrangement, and gene information
interphase: the time interval between nuclear divisions. During this phase, a cell increases in mass, roughly doubles the cytoplasmic components, and duplicates its chromosomes.
karotype chart: a picture of chromosomes arranged in homologous pairs
Klinefelter syndrome: a trisomic disorder in which a male carries an XXY condition.
meiosis: two-stage cell division in which the chromosome number of the parental cell is reduced by half. Meiosis is the process by which gametes are formed.
mitosis: a type of cell division in which a daughter cell receives the same number of chromosomes as the parent cell
monosomy: the condition where there is a single chromosome in place of a homologous pair
oocytes: immature eggs
ootid: an unfertilized ovum
polar bodies: cells that contain all the genetic information of a haploid ovum but lack sufficient cytoplasm to survive; formed during meiosis in females
sex chromosomes: the pair of chromosomes that have a role in the sex of an individual
sexual reproduction: the production of offspring from the union of two sex cells, one from each different parent. The genetic makeup of the offspring is different from that of either parent.
sister chromatids: a chromosome and its duplicate, attached to one another by a centromere. The pair remains attached until separated during mitosis.
spindle fibres: protein structures that guide chromosomes during cell division
synapsis: the pairing of homologous chromosomes
tetrad: a pair of homologous chromosomes each with two chromatids
trisomy: the condition where there are three homologous chromosomes in place of a homologous pair
Turner syndrome: a monosomic disorder in which a female has a single X chromosome
zygote: a cell resulting from the union of a male and female sex cell, until it divides and then is called an embryo
References
1. McGraw-Hill Ryerson Biology 11
2. Mistakes in Meiosis. http://www.sumanasinc.com/webcontent/animations/content/mistakesmeiosis/mistakesmeiosis.html
3. Mitosis in Onion Root Tip Cells. http://www.marietta.edu/~biol/introlab/Onion%20root%20mitosis.pdf.
4. Nelson Biology 11
5. The Ontario Curriculum Grades 11 and 12 Science. 2008.
2. Mistakes in Meiosis. http://www.sumanasinc.com/webcontent/animations/content/mistakesmeiosis/mistakesmeiosis.html
3. Mitosis in Onion Root Tip Cells. http://www.marietta.edu/~biol/introlab/Onion%20root%20mitosis.pdf.
4. Nelson Biology 11
5. The Ontario Curriculum Grades 11 and 12 Science. 2008.