Mitosis and Meiosis Review

Cell Cycle, Mitosis,

and Meiosis

Biology EOC Tutoring

Benchmarks

SC.912.L.16.8 Explain the relationship between mutation, cell cycle, and
uncontrolled cell growth potentially resulting in cancer

SC.912.L.16.14 Describe the cell cycle, including the processes if mitosis.
Explain the role of mitosis in the formation of new cells and its importance
in maintaining chromosome number during asexual reproduction

SC.912.L.16.16 Describe the processes of meiosis, including independent
assortment and crossing over. Explain how reduction division results in the
formation of haploid gametes or spores

You Must Know

The differences and similarities in the processes of
mitosis and meiosis and relate these to the processes of
sexual and asexual reproduction.

How mitosis and meiosis lead to genetic variation.

The relationship between mutation, cell cycle, and
uncontrolled cell growth potentially resulting in cancer.

The cell cycle, including the process of mitosis and be
able to explain the role of mitosis in the formation of
new cells and its importance in maintaining
chromosome number during sexual reproduction.

Cell Cycle

• Interphase

• Gap 1

• Synthesis

• Gap 2

• Mitosis

• Prophase

• Metaphase

• Anaphase

• Telophase

Cytokinesis

Cell Cycle

Mitosis and Meiosis Similarities

• Mitosis and meiosis are the two forms of cell division.

• Both begin with a diploid cell (two copies of every chromosome) and

require the entire DNA to be replicated before they begin (duplicate
each homologous chromosome so that it is made of 2 identical sister
chromatids).

•Before each one begins, the cells go through Interphase where the DNA is
replicated

Mitosis

• Cell division

• Produces two identical diploid daughter

cells

• Occurs in body cells to grow and repair

Mitosis phases

Prophase: The genetic material in
the nucleus condenses and the

duplicated chromosomes

become visible. The nucleolus

disappears and the nuclear

envelope begins to break down,
spindle fibers also start extending

from both poles of the cell.

Metaphase: The duplicated

chromosomes become line up in

the center of the cell; spindle
fibers attach themselves to the

centromere of the chromosomes.

Anaphase: The stage of mitosis in

which the duplicated sets of

chromosomes separate and two
identical groups move to opposite

poles of the cell.

Telophase: A nuclear membrane
re-forms around each new group

of chromosomes.

Interphase- The cell grows and

replicates its DNA, it is not a phase

of mitosis

Cytokinesis- Cell separates

Mitosis

• THE FINAL PRODUCTS ARE TWO IDENTICAL DIPLOID CELLS

Any of various malignant neoplasms characterized by the
proliferation of anaplastic cells that tend to invade
surrounding tissue and metastasize to new body sites.

Cells growing out of control!

Cancer

• Error in cell growth with

causes uncontrolled cell
growth

• Has environment and

genetic variables

• may result from mutations

that affect the proteins that
regulate the cell cycle.

Meiosis

• Cell division

• Produces four different

haploid daughter cells
(gametes)

• Occurs in sex cells to form

gametes

• Meiosis I: Begins with diploid

cell

Meiosis I

• Prophase I: chromosomes appear (already duplicated), spindle fibers form, nuclear

membrane breaks down. Homologous chromosomes form tetrads and crossing over
occurs between homologous chromosomes (increases genetic variation)

• Metaphase I: Homologous chromosomes (the same chromosome, but they are not

identical – one version of the chromosome is from the mother and the other from the
father. They have the same genes, but different copies of the gene) line up in PAIRS.
There is an equal chance that the chromosome will be on the left as on the right. This is
called independent assortment and increases genetic variation.

• Anaphase I: HOMOLOGOUS CHROMOSOMES begin to separate.

• Telophase I and Cytokinesis: Homologous chromosomes continue to separate and the

cytoplasm divides; nuclear membrane reforms. THE FINAL PRODUCTS MEIOSIS I ARE TWO
DIFFERENT HAPLOID CELLS

Meiosis II: Occurs in two haploid cells at the same time

• Prophase II: Chromosomes re-appear

• Metaphase II: Chromosomes line up in a straight line

• Anaphase II: SISTER CHROMATIDS begin to separate

• Telophase II and Cytokinesis: sister chromatids continue to separate and

the cytoplasm divides; nuclear membrane reforms. THE FINAL PRODUCTS
ARE DIFFERENT HAPLOID GAMETES (cells).

Meiosis
• It produces 4 cells that are different.

• Gametes or sex cells have half the number of

chromosomes as an organism’s other cells.

• Meiosis allows a plant to produce offspring

plants with unique (one of a kind)
combinations of genetic material.

Crossing Over

• Homologous chromosomes

exchange parts of their DNA

• Creates variation in gametes

Multiple Choice

What is crossing over? When does crossing over occur?  

• Crossing over is the exchange of genetic information between homologous pairs of chromosomes. It occurs during Prophase I of Meiosis I.  

• Crossing over is the process of exchanging genetic material between two organisms. It occurs during Prophase II of Meiosis II.  

• Crossing over occurs during meiosis when homologous chromosomes pair up. It occurs during Prophase I I of Meiosis I.  

• Crossing over is the process of combining genetic information from two parents. It occurs during Prophase I of Meiosis II.  

Multiple Select

What are the benefits of crossing over?

• Increases variation in the gametes.

• Helps survival in the population as multiple combinations of alleles occurs with a greater chance that one change in the environment will not eliminate the entire species

• Decreases the chances of survival of the species

• Decreases the genetic diversity of the population

Nondisjunction

• Homologous chromosomes

fail to separate during
meiosis

• Can lead to Down

Syndrome, Turners
Syndrome, and Klinefelters
Syndrome

Multiple Choice

•What is nondisjunction?

• the failure of homologous chromosome pairs to separate during anaphase I of meiosis.

• The inability of chromosomes to replicate correctly during meiosis

• The misalignment of chromosomes during prophase I

• The incorrect pairing of sister chromatids during metaphase I

SC.L16.17 Compare and Contrast

Mitosis and meiosis

Feature

Meiosis

Mitosis

Definition

A type of cellular reproduction in which
the number of chromosomes are reduced
by half.

A process of asexual reproduction in which
the cell divides in two producing a replica,
(the number of chromosomes stays the same)

Function

Sexual reproduction

Cellular Reproduction & general growth and
repair of the body

Type of cell produced

Sex cell known as gametes
(egg and sperm)

Body cell (blood cells, epithelial, muscle,
nerve cells etc)

Type of Reproduction

Sexual

Asexual

Daughter cells are Genetically

Different from parent cell
(shows genetic diversity)

Identical to parent cell
(exact replica of parent cell)

Continuation….

Feature

Meiosis

Mitosis

Crossing over

Yes, mixing of chromosomes
can occur

No, crossing over cannot
occur

Paring of homologous
chromosomes

Yes, then homologous
chromosomes separate and
produce 4 haploid daughter
cells.

No

Beginning cell

Diploid cell

Diploid cell

Number of cells produced

4

2

Number of chromosomes

Half the original cell

Same as original cell

End product

4 Haploid cells
(the cells show genetic
diversity)

2 diploid cells
(an exact replica of the
parent cell)

II

II

II

II

I

I

I

I

1

2

2

4

Match

Match the correct statements with the corresponding type of cell division.

​

• Mitosis

• Meiosis

• Mitosis

• Meiosis I

• Mitosis

the division of the replicated contents of the nucleus of somatic cells

Haploid Cells

diploid cells

Homologous chromosomes align in the center of the cell

identical daughters' cells

• the division of the replicated contents of the nucleus of somatic cells

• Haploid Cells

• diploid cells

• Homologous chromosomes align in the center of the cell

• identical daughters' cells

Match

Match the correct statements with the corresponding type of cell division.

​

• Meiosis I and II

• Meiosis I

• Mitosis

• Meiosis II

• Mitosis

Sexual reproduction

Crossing over

asexual

Final division that creates 4 haploid cells

cellular reproduction, general growth

• Sexual reproduction

• Crossing over

• asexual

• Final division that creates 4 haploid cells

• cellular reproduction, general growth

Similarities

between mitosis

and meiosis

Both are forms of cell division.

Both begging with diploid cells.

Both occur within the nucleus of the cell.

Both go through the same steps known as
Prophase, Metaphase, Anaphase and
Telophase.

Both have in common cytokines is (The
cytoplasm divides)

Comparing Methods of Reproduction

Asexual Reproduction

Sexual Reproduction

Advantages

Produce many organisms
quickly

Since offspring are genetically
diverse, they may be able to
survive in more varied
conditions.

Disadvantages

No genetic variation
A factor such a toxin in the
environment that harms one
offspring can harm all of
them

Needs to find a mate
Produces relatively few
offspring

Asexual vs. Sexual Reproduction

Asexual

• One parent

• Identical offspring

• Variation only thru mutations

• Examples: budding,

fragmentation, fission

Sexual

• Two parents

• Offspring different from parents

• More variation

• Fertilization (fusion of gametes)

Open Ended

Explain cell differentiation.

• Be able to put pictures of cells in

various stages of the cell cycle in
order….IPMATC

31

Multiple Choice

Mitosis and meiosis are processes involved in cellular reproduction. Which of the following describes and event that results from mitosis but NOT meiosis?

• two stages of cell division

• replication of cellular genetic material

• daughter cells that are identical to the parent cell

• •four daughter cells that are produced from each parent cell

Multiple Choice

How are sexual reproduction and asexual reproduction different from each other?

• Sexual reproduction requires two parents and asexual reproduction requires only one parent

• Asexual reproduction requires two parents and sexual reproduction requires only one parent

• Mutation rates are lower in sexual reproduction than in asexual reproduction

• Asexual reproduction occurs only in multicellular organisms

Multiple Choice

Which type of reproduction leads to increased genetic variation on a population?

• Parthenogenesis

• Asexual reproduction

• Sexual reproduction

• Vegetative reproduction

Multiple Choice

Which of the following phrases best describes cancer?

• Absence of cyclins in the DNA

• •multiple gene mutations on a chromosome of DNA

• •uncontrolled cell growth caused by mutations in genes that control the cell cycle

• •presence of genetic defects caused by hereditary disorders

Multiple Choice

Which of the following best describes meiosis?

• •It is carried out in all tissues that require cell replacement.

• •It occurs only in cells in the reproductive structures of organisms.

• •It happens in all tissues except the brain and spinal cord.

• •It is the first stage of mitosis.

Multiple Choice

•A scientist wants to change the DNA of a sexually reproducing organism and have the new DNA present in every cell of the organism. In order to do this after the DNA in which of the following?

• Zygote

• Placenta

• Testes of the father

• Ovaries of the mother

Multiple Choice

The diagram below shows homologous chromosomes during prophase I of meiosis.

Which of the following correctly describes the process being illustrated?

• •mutation in which the DNA content of the gene is altered

• segregation of sister chromatid

• condensation and segregation of alleles

• •crossing-over in which alleles are exchanged