MEIOSIS

for General Biology 1 Grade 11

Quarter 1/ Week 5

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 FOREWORD

This self-learning kit serves as a guide for STEM

students in understanding the different stages of meiosis
and its significance and application. This may become an
instrument in the development of students who are
critical problem solvers, lifetime learners, responsible
stewards of Mother Earth, truth seekers, impartial decision
makers, responsive and ingenious citizens and effective
communicators.

This may help the students in their journey as they

explore the intricacies of LIFE through science amidst
COVID-19 pandemic.

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OBJECTIVES
At the end of the lesson, learners shall be able to:
K: describe the different stages of meiosis;
S: label the different stages of meiosis; and
A: display appreciation on the important role played by
meiosis in the lives of organisms.

LEARNING COMPETENCIES

Describe the stages of mitosis/meiosis given 2n = 6

(STEM_BIO11/12-id-f-7)

Explain the significance or applications of mitosis/meiosis

(STEM_BIO11/12-Id-f-9)

I. WHAT HAPPENED

PRE-ACTIVITY/PRE-TEST

True or False. Determine if the following statements are correct or

incorrect. Write T if the statement is correct and F if incorrect. Write your
answers in your notebook.

___1. A cell’s DNA is replicated during the M phase of the cell cycle.
___2. Another word for chromosome is chromatid, which is an exact
copy of the original chromosome.
___3. The stage in which a cell divides is called the mitotic phase.
___4. In meiosis, cellular division occurs three times.
___5. Plant and animal cells have many differences. One difference is
the plant cells have a cell plate.
___6. Meiosis usually results in the formation of four genetically identical
cells.
___7. Chromosome number is not changed during mitosis.
___8. Crossing-over rarely occurs in meiosis because homologous
chromosomes rarely form during mitosis.
___9. Cells divide to repair tissues, to grow and to reproduce.
___10. Two members of a pair are called homologous chromosomes.
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II. WHAT I NEED TO KNOW

DISCUSSION

There are two types of cell division, mitosis and meiosis. Mitosis allows
organisms to reproduce asexually, grow and repair of worn-out or damaged
tissues. Meiosis on the other hand, is important in sexual reproduction and
genetic diversity among sexually reproducing organism.

Many of the steps of meiosis closely resemble corresponding steps in

mitosis. Meiosis, like mitosis, is preceded by the duplication of chromosomes.
However, this single duplication is followed by not one but two consecutive
cell divisions called meiosis I and meiosis II. These two divisions result in four
daughter cells (rather than the two daughter cells of mitosis), each with only
half as many chromosomes as the parent cell—one set, rather than two.
Meiosis reduces the amount of genetic information resulting to its importance
in sexual reproduction and genetic diversity among sexually reproducing
organism.

OVERVIEW OF MEIOSIS

The overview of meiosis

shows for a single pair of
homologous chromosomes in a
diploid cell, that both members
of the pair are duplicated and
the copies sorted into four
haploid daughter cells. Recall
that sister chromatids are two
copies of one chromosome,
closely associated all along their
lengths; this association is called
sister chromatid. Together, the
sister chromatids make up one
duplicated chromosome. In
contrast, the two chromosomes
Figure 1. Overview of meiosis: how meiosis
of a homologous pair are
reduces chromosome number. After the
individual chromosomes that were chromosomes duplicate in interphase, the
inherited from different parents. diploid cell divides twice, yielding four
haploid daughter cells.

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Figure 2. Meiosis I and Meiosis II. Describes in detail the stages of the two divisions of
meiosis for an animal cell whose diploid number is 6 (2n = 6).

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Table 1. Stages of Meiosis

STAGES OF MEIOSIS I STAGES OF MEIOSIS II

PROPHASE I PROPHASE II

Prophase of the first meiotic Meiosis II is initiated immediately

division is typically longer and after cytokinesis, usually before the
more complex when compared to chromosomes have fully
prophase of mitosis. It has been elongated. In contrast to meiosis I,
further subdivided into the meiosis II resembles a normal
following five phases based on mitosis.
chromosomal behaviour:
The nuclear membrane disappears
1. Leptotene
by the end of prophase II. The
2. Zygotene
3. Pachytene chromosomes again become
4. Diplotene and compact.
5. Diakinesis
METAPHASE I METAPHASE II
The bivalent chromosomes align At this stage the chromosomes
on the equatorial plate. The align at the equator and the
microtubules from the opposite microtubules from opposite poles
poles of the spindle attach to the of the spindle get attached to the
pair of homologous. kinetochores of sister

ANAPHASE I ANAPHASE II
The homologous chromosomes It begins with the simultaneous
separate, while sister chromatids splitting of the centromere of each
remain associated at their chromosome (which was holding
centromeres. the sister chromatids together),
allowing them to move toward
opposite poles of the cell.

TELOPHASE I TELOPHASE II
The nuclear membrane and Meiosis ends with telophase II in
nucleolus reappear, cytokinesis which the two groups of
follows and this is called as diad of chromosomes once again get
cells. Although in many cases the enclosed by a nuclear envelope;
chromosomes do undergo some cytokinesis follows resulting in the
dispersion, they do not reach the formation of haploid daughter
extremely extended state of the cells.
interphase nucleus.

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IMPORTANCE OF MEIOSIS

Through the process of meiosis, rapid generation of new genetic

combinations happen to sex cells during their development. There are three
mechanisms that contribute to this genetic variation: independent
assortment, crossing-over, and random fertilization.

1. Independent Assortment

Humans have 23 pairs of homologous chromosomes. In fact, these 23

chromosomes that you receive from your parents are a matter of chance.

The random distribution of homologous chromosomes during meiosis is

called independent assortment. In metaphase I, maternal and paternal
chromosomes lined up at the equator of the cell, but eventually, these are
pulled apart randomly at opposite poles in anaphase I. Each of the 23 pairs
segregates or separates independently. Each daughter cell gets one
chromosome from each homologous pair.

Independent assortment is shown in Figure 3 with just four pairs of

homologous chromosomes for simplified illustration. With four pairs of
homologous chromosomes, you may come up with 24 or 16 possible
combinations. Thus, 223 (about eight million) with different gene
combinations can be produced from one original cell by this mechanism
alone for humans.

Figure 3. The alignment of chromosomes in the middle of the metaphase plate is random
and can result in astounding
Crossing-Over and Random possibilities in genetic variability.
Fertilization
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 Another factor that contributes to genetic variation is crossing-over. This
occur during prophase I of meiosis, where chromosomes line up in the
process called synapsis, while sections of their DNA are exchanged. DNA
exchange during crossover adds more recombination probabilities to the
independent assortment of chromosomes that occur later in meiosis. The
number of genetic combinations in the gametes is practically unlimited. In
addition, because the zygote that forms a new individual is created by the
random fusion of two gametes, fertilization squares the number of possible
outcomes (223 x 223 = 64 trillion).

Figure 4. Crossing-over between homologous chromosomes adds to genetic variability.

Activity 1

Let’s Create Something. Show the stages of meiosis by describing what

happens in each stage. Choose only one type of presentation that you
prefer from the choices below:
1. Newspaper article
2. Poem/song
3. Create a model
4. Animated movie

Possible Rubric:

20 pts Knowledge - a clear and correct understanding of meiosis

20 pts Creativity - demonstrates a high level of creativity

10 pts Presentation - output is clear, thought out, and easy to

understand

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Activity 2

Name that thing! In your notebook, label the following stages of meiosis:

III. WHAT I HAVE LEARNED

EVALUATION/POST-TEST

Multiple Choice. Read carefully and choose the letter that best corresponds
to your answer.

1. What is the significance of crossing over in meiosis?

a. ensures that chromosomes are evenly divided into daughter cells
b. can lead to genetic variation in daughter cells
c. can create gaps in the chromosome DNA for RNA to bind
d. allows for spindles to connect to the chromosomes to pull it apart

2. Meiosis I is reductional division and meiosis II is equational division because

of_____________.
a. separation of chromatids
b. crossing over
c. disjunction of homologous chromosome
d. pairing of homologous chromosome
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3. The following are stages of prophase I, except_____________.
a. pachytene b. zygotene c. leptotene d. dipotene

4. Comparing mitosis and meiosis, which of the following is an accurate

statement?
a. Most plant and animal cells undergo mitosis; however, only animals
can perform meiosis.
b. Most plant and animal cells undergo mitosis; however, only plants
can perform meiosis.
c. Most plant and animal cells undergo mitosis; both plants and animals
can perform meiosis.
d. Plants perform mitosis while animals perform meiosis.

5. Continuous variations are attributed to ____________.

a. polyploidy c. mutation
b. crossing over d. chromosomal aberrations

6. The reason for daughter cells to differ from parent cells and also each
other in meiosis is ____________.
a. segregation and crossing over
b. segregation and independent assortment
c. segregation, crossing over, and independent assortment
d. independent assortment and crossing over

7. If crossing over will not happen,_________________.

a. cells cannot complete meiosis
b. genetic recombination may be affected
c. chromosomes will undergo nondisjunction
d. meiosis cannot produce haploid sex cells

8. Why do cells undergo meiosis?

a. to help repair the cell c. to produce sex cells
b. to help the cell grow d. none of these

9. One of these events does not take place during meiosis, except_______.
a. one succession division without any DNA replication
b. chiasmata formation and crossing over
c. segregation of homologous chromosome
d. separation of sister chromatids

10. Independent assortment of chromosomes at metaphase I results in an

increase in the variability of ____________.
a. sex chromosome c. sister chromatids
b. homologous chromosomes d. recombination of genetic traits

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REFERENCES

McKee, B.D. (2004). Homologous Pairing and Chromosome Dynamics in

Meiosis and Mitosis. Biochimica et Biophysica Acta (BBA)-Gene
Structure and expression, 1667 (1-3), 165-180.

Ramos, A. (2017) Exploring Life Through Science Series: General Biology 1.

Phoenix Publishing House Inc.

Sullivan, M., & Morgan, D. O. (2007). Finishing Mitosis, One Step at a Time.
Nature Reviews Molecular Cell Biology, 8(11), Sciences, 178(1052), 277-
299.

Urry L., Cain, M., Wasswerman S., Minorsky P., Reece J. (2017). Campbell
Biology. Pearson Education Inc.

Wilkins, A.S., & Holiday, R. (2009). The Evolution of Meiosis from Mitosis.
Genetics, 181 (1), 3-12.

Retrieved from https://youtu.be/xsrH050wnIA

Retrieved from https://youtu.be/VzDMG7ke69

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 DEPARTMENT OF EDUCATION
SCHOOLS DIVISION OF NEGROS ORIENTAL

SENEN PRISCILLO P. PAULIN, CESO V

Schools Division Superintendent

JOELYZA M. ARCILLA EdD

OIC - Assistant Schools Division Superintendent

MARCELO K. PALISPIS EdD JD

OIC - Assistant Schools Division Superintendent

NILITA L. RAGAY EdD

OIC - Assistant Schools Division Superintendent / CID Chief

ROSELA R. ABIERA
Education Program Supervisor – (LRMS)

ARNOLD R. JUNGCO
PSDS – Division Science Coordinator

MARICEL S. RASID
Librarian II (LRMDS)

ELMAR L. CABRERA
PDO II (LRMDS)

MARY JOYCEN A. ALAM-ALAM

EASTER ROSE U. TOLOMIA
Writers

NOELYN E. SIAPNO
Layout Artist
________________________________

ALPHA QA TEAM

LIEZEL A. AGOR
EUFRATES G. ANSOK JR.
JOAN Y. BUBULI
MA. OFELIA I. BUSCATO
LIELIN A. DE LA ZERNA
DEXTER D. PAIRA

BETA QA TEAM

ZENAIDA A. ACADEMIA LIEZEL A. BESAS

DORIN FAYE. D. CADAYDAY LIELIN A. DE LA ZERNA
MERCY G. DAGOY PETER PAUL A. PATRON
RANJEL D. ESTIMAR THOMAS JOGIE U. TOLEDO
MARIA SALOME B. GOMEZ JOAN B. VALENCIA
JUSTIN PAUL ARSENIO S. KINAMOT
ARJIE T. PALUMPA

DISCLAIMER

The information, activities and assessments used in this material are designed to provide
accessible learning modality to the teachers and learners of the Division of Negros Oriental. The
contents of this module are carefully researched, chosen, and evaluated to comply with the set
learning competencies. The writers and evaluator were clearly instructed to give credits to
information and illustrations used to substantiate this material. All content is subject to copyright
and may not be reproduced in any form without expressed written consent from the division.

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SYNOPSIS ANSWER KEY

This self-learning kit is intended to aid

the learners in understanding the different
stages of meiosis under the learning
competency ―Describe the stages of
mitosis/meiosis given 2n = 6” and ―Explain the
significance or applications of
mitosis/meiosis‖ as part of the most essential
learning competencies in the K-12
curriculum.

Learners are expected to realize the

objectives of the competencies set at the
beginning of this learning kit. This learning kit
will help learners retain information and
concept through application. Let us all learn
and have fun in the process.

ABOUT THE AUTHORS

MARY JOYCEN A. ALAM-ALAM is a Special Science
Teacher I (SPST-I) in Dauin Science High School. She
earned her Bachelor of Secondary Education major
in Biological Science at Negros Oriental State
University in 2016. She was also a DOST-SEI scholar
under R.A. No. 10612.

EASTER ROSE UBAG TOLOMIA is a Senior High

School Teacher in Sibulan National High School-
Balugo Extension. She finished her Bachelor of
Science in Nursing at St. Paul University
Dumaguete and took Continuing Professional
Education at Foundation University. She
graduated Master of Arts in Education Major in
General Science at Foundation University.

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