THE CELL CYCLE
for General Biology 1 / Grade 11
Quarter 1/Week 3
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FOREWORD
This self-learning kit (SLK) is carefully planned and
prepared for learners to be equipped with the basic and
necessary concept in Science and to enhance their
technological skills. This module, in some way, is designed
to help them acquire the skills they need in the 21st century.
In this learning kit, the learners will be able to gain
knowledge in characterizing the phases of cell cycle and
its control points. Moreover, this learning kit will give ideas
to learners about some disorders and diseases that result
from the malfunction of the cell during the cell cycle. As
they read through the lessons and perform the activities in
this module, they will develop their inventive thinking skills
and love for Science.
As the learners go on with this simple module, may
they understand and appreciate Biology better.
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OBJECTIVES:
At the end of the lesson, the learners shall be able to:
K: describe the different characteristics of the
phases (or parts) of the cell cycle and their control
points,
S: determine the associated disorders and
diseases as a result of malfunction of cell
during the process of cell cycle
A: infer on the importance of cell cycle regulation
to the normal functioning of the body.
LEARNING COMPETENCY:
Characterize the phases of the cell cycle and their control
points (STEM_BIO11/12-Id-f-6)
Identify disorders and diseases that result from the
malfunction of the cell during the cell cycle (STEM_BIO11/12Id-f-10)
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I. What Happened
Hi. I’m Rian!
…and I’m John!
We are here to join you in your quest towards learning our lesson
for today which is about the CELL CYCLE. We will also discover
some of the different disorders and diseases that result from the
malfunction of the cell during the cell cycle.
I guess this
would be fun!
Are you ready
to learn?
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PRE-ACTIVITIES/PRE-TEST:
SCI-QUEST! #1
A. WORD SEARCH HUNT. Find the following words in the puzzle below
and encircle them. (Teachers will provide another copy of this page.)
GAP ZERO
GROWTH
SYNTHESIS
CHECKPOINT
REPLICATION
CELLS
CHROMOSOMES
INTERPHASE
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ACTIVITY 2. Complete the table below by checking the correct column for
each statement. Do this activity in your notebook.
STATEMENT
INTERPHASE
M PHASE
1. Cell growth occurs
2. Chromosomes are
distributed equally to
daughter cells.
3. Chromosomes are
duplicated.
4. DNA synthesis takes place
5. Cytoplasm divides
immediately after this
period.
Based on the activity, what are the events that take place during the
interphase? How about in the M phase?
Which of these events do you think will take longer?
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II. What I Need To Know
Don’t worry Rian, in this
section, we will go through
the process of cell cycle, its
phases, and its control
points.
John, do you have any
idea when and how
cells divide?
Let us pay close attention so that we will
be able to understand as well as answer
the next challenge after this section!
We heard Sir Paul will help us with our
lesson for today…
Hello! I am teacher Paul and I’m ready to
help you understand the topic on CELL
CYCLE! We are going to tackle also
what might happen when there are
aberrations during cell cycle.
Before we proceed, let me ask you
this essential question: HOW DO
HEALTHY CELLS DECIDE WHEN TO
DIVIDE?
Trivia!
The body is made up of about 100 trillion cells, all from a single
fertilized cell at the start of life! Amazing right?
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SCI-LEARN!
All organisms reproduce for one reason – to ensure the survival of
their species. Reproduction makes use of the process of cell division.
Cell division is important for two reasons:
➢ To be able to produce offspring
➢ To generate new cells that will replace worn out or
damaged cells
There are two types of cell division, namely mitosis which happens in
body cells or somatic cells and meiosis which involves the gametes or sex
cells.
In order to better understand cell division, you need to learn first the
cell cycle. This cycle involves distinct and regular phases of growth, DNA
duplication, and cell division that are needed to allow growth and repair.
The cell cycle is divided into two main stages:
1. Interphase – non-dividing stage (G1, S, and G2 phases, G0)
2. Cell division – dividing stage (mitosis for somatic cells and
meiosis for sex cells
Self-Check!
What are the two main stages of cell cycle?
Write your answers in your notebook.
1.________________________
2.________________________
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STAGES OF CELL CYCLE
Figure 1: The stages of
cell cycle.
STAGE 1: INTERPHASE
Interphase is the growth period in the cell cycle characterized by
cell preparation by replication of its genetic information and all of its
organelles.
Three Main Parts of Interphase
Gap 1 (G1) Phase
Synthesis (S) Phase
➢ Cell carries out its
➢ DNA synthesis
normal metabolic
(replication) occurs;
functions (example:
cells make a copy
during G1 phase,
of its genetic
an intestinal cell
material in the form
performs its primary
of nuclear DNA
duty to absorb
➢ Cells spend
nutrients)
considerable
➢ Cells increase their
amount of time and
size
energy to make
➢ Cell prepares for
copies of its
DNA synthesis
chromosomes
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Gap 2 (G2) Phase
➢ Cells continue to
carry out their
normal functions
and also undergo
further growth and
synthesis of RNA and
proteins
➢ This stage contains
a critical
“checkpoint”
before transitioning
to the next stage
which is cellular
division
STAGE 2: CELLULAR DIVISION: MITOSIS AND MEIOSIS
(Note: This will be discussed in the next module)
Some cells undergo the cell cycle only once or they stop dividing
and enter the stage known as the gap zero or G0. In this stage, cells are
unlikely to divide but still continue to perform normal functions.
Such cells, like neuron cells and heart muscle cells that are highly
differentiated or specialized and that the body cannot easily replace, are
said to be permanently in G0.
Immune cells that are needed at a later time, such as lymphocytes,
remain in G0 for many years until such time that the body needs to
recognize an invader. Only when an invader binds to the lymphocyte’s
receptor that the lymphocyte starts to divide rapidly to help get rid of the
infection.
CELL CYCLE CHECKPOINTS
In order to prevent mutations/chromosomal aberrations and ensure
major events occur at correct times, several cell cycle checkpoints are
present at various times in the cycle preventing cells from proceeding to
the next stage unless all criteria had been met.
Figure 2: Stages of cell cycle and their
respective control points.
“Checkpoints” or control points are moments when the cell can
“check” its internal conditions and “decide” whether to progress to the
next phase or remain. It is similar to what happens during a police
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operation checkpoint. When you have met the requirements asked by
the police officer in-charge, you can go pass the checkpoint.
The main activities done during cell checkpoint are summarized below.
G1 Checkpoint
S Checkpoint
G2 Checkpoint
M Checkpoint
✓ Restriction point
to enter S phase
✓ Checks DNA
damage and
favorable
conditions
✓ Availability of
growth factors
✓ G1 checkpoint
can direct cell
into quiescence
(G0) if conditions
are not
favorable
✓ Checks for DNA
damage
before/
during
replication
✓ Prevents
reduplication of
DNA
✓ Allows entry
into mitosis
✓ Checks DNA
damage
✓ Ensures DNA
is
duplicated
✓ During mitosis:
allows entry to
anaphase
✓ Ensures all
chromosomes
aligned at
metaphase
plate and
attached to
the spindle
fiber
MALFUNCTION DURING CELL CYCLE
The key to understanding the
different disorders and diseases as a
result of the malfunction of cells lies on
our knowledge of the cell cycle. If you
can still recall in the previous discussion ,
we have tackled that cell cycle has
different phases and each part has its
own checkpoint in order to monitor the
activities of the cell. Failure to regulate
cell activities may result to various
disease and disorder. Some of these are
mentioned on the next page.
Figure 1: Comparison between a normal cell
and a cancer cell undergoing cell division.
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A. CANCER
One of the most common disorder we know today but without cure
yet is cancer. Cancer refers to a group of diseases characterized by
uncontrolled and abnormal cell division. It occurs when there is a
disruption in the cell cycle. Instead of stopping and starting at appropriate
points, cancerous cells divide continuously until a disorganized
solid mass of cells called tumor is formed.
Tumors can be categorized as benign or malignant. Benign tumors
are cancer cells that remain clustered together, which may be harmless
or not and can probably be cured when removed out of the body.
Malignant tumors are cancer cells that has break away or metastasized.
This cancer cells are transported to the bloodstream of the lymphatic
system to the other parts and form more tumors.
What causes cancerous cells?
➢ Cancer is caused mainly by changes or mutations to the
DNA within cells.
What are some of the risk factor contributing to cancer?
➢ Lifestyle factors (e.g.: smoking, high-fat diet, working with
toxic chemicals)
➢ Family history, inheritance, and genetics (e.g., inheritance of
breast cancer)
➢ Some genetic disorder
➢ Exposure to certain viruses (e.g., cervical cancer which is
caused by human papilloma virus)
➢ Environmental exposures (e.g., exposure to pesticides and
fertilizers, radiations, and carcinogens)
Why are tumors dangerous inside the body?
➢ Generally, cancer cells do not perform the specialized
functions of the normal cells in the body
➢ Example, if the cancer cells are in the brain, they do not
perform their supposed function which is to transmit
electrical signals for response. Moreover, if they continue to
grow and form tumors, it can cramp the brain in the limited
skull. This might affect the other parts of the brain and their
functions because cancer cells also compete for nutrients
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and blood supply with other healthy cells. If left unchecked,
it may hinder the proper functioning of the body.
How is cancer treated?
➢ Chemotherapy – uses certain drugs to kill actively dividing
cells. This procedure is systemic, which means that drugs are
introduced throughout the body orally (taken by mouth) or
intravenously (injection).
➢ Surgery – involves removal of the cancerous body part
➢ Radiation therapy – involves the exposure of X-rays to kill
cancer cells and shrink the tumor size
Self-Check!
What are the possible things that might happen to cancer cells?
______________________________________________________________
________
B. GENETIC DISORDERS
A change in the number or structure of chromosomes can
dramatically change the traits of an organism and can cause serious
problems. Abnormal chromosomes most often happen as a result of an
error during cell division. Chromosome abnormalities often happen due to
one or more of these:
➢ Errors during dividing of sex cells (meiosis)
➢ Errors during dividing of other cells (mitosis)
➢ Exposure to substances that can cause birth defects
(teratogens)
Figure 2: Normal human karyotype. Male karyotype (left)
and female karyotype (right).
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Karyotyping is the process by which photographs of chromosomes are
taken in order to determine the chromosome complement of an individual,
including the number of chromosomes and any abnormalities.
Numerical abnormality also called aneuploidy, a condition which occurs
when an individual has a missing chromosome from a pair (monosomy) or has
more than two chromosomes of a pair (trisomy, tetrasomy, etc.).
Examples of chromosomal abnormalities under this category include the
following:
Down Syndrome (Trisomy 21)
✓ The most common disorder of trisomy is Down
syndrome, wherein the 21st chromosome has
three instead of two chromosomes.
✓ Most cases of Down syndrome are not due to
inheritance but on random mistakes during
formation of reproductive cells of the parents.
✓ Physical manifestations: Short neck, with
excess skin at back of the neck. Flattened
Figure 3: Child with
Down Syndrome (file
facial profile and nose. Small head, ears, and
retrieved from Google marked
mouth. Upward slanting eyes.
as “labeled for reuse”)
Turner Syndrome (45, XO)
✓ A condition that affects only female as a result
of one of the X chromosomes (sex
chromosome) is missing or partially missing.
✓ Physical manifestations: Webbed neck, short
stature, swollen hands and feet. Some have
skeletal abnormalities, kidney problems,
and/or congenital heart defect.
Klinefelter Syndrome (47, XXY)
✓ A condition resulting from two or more X
chromosomes in males
✓ Manifestations are typically more severe if
three or more X chromosomes are present as
in (48, XXXY) or (49, XXXXY).
✓ Physical manifestations: Primary features are
infertility and small poorly functioning testicles.
Sometimes includes weaker muscle, greater
height, poor coordination, less body hair, breast
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Figure 4: Turner
Syndrome (file retrieved
from Google marked as
“labeled for reuse”)
Figure 5: Klinefelter
Syndrome (file retrieved
from Google marked as
“labeled for reuse”)
growth and less interest in sex.
Trisomy X Syndrome (47, XXX)
✓ Characterized by the presence of extra X
chromosome in each cell of a female
✓ Physical manifestations: Often taller than
normal, affected individuals have usually
mild symptoms to none at all. Occasionally
there are learning difficulties, delayed
speech, decreased muscle tone, seizures,
or kidney problems.
Figure 6: Trisomy X (file
retrieved from Google
marked as “labeled for
reuse”)
Patau Syndrome (Trisomy 13)
✓ Caused by having an additional copy of
chromosome 13 in some or all of the
body’s cells.
✓ Physical manifestations: Clenched hands,
cleft lip or palate, extra fingers or toes
(polydactyly), hernias, kidney, wrist or
scalp problems, low-set ears, small head,
undescended testis.
Edward Syndrome (Trisomy 18)
✓ Caused by having additional copy of
chromosome 18
✓ Physical manifestations: Cleft palate,
Clenched fists, defects of lungs, kidneys
and stomach, deformed feet, heart
defects, low-set ears,
severe developmental delays, chest
deformity, slowed growth, small head, small
jaw.
Figure 7: Patau Syndrome
(file retrieved from Google
marked as “labeled for
reuse”)
Fig. 8: Edward Syndrome
(file retrieved from Google
marked as “labeled for
reuse”)
Structural abnormalities occur when the chromosome’s structure is
altered, which can take several forms such as: Deletion – a portion of a
chromosome is missing or deleted; Duplication – segment of a
chromosome is repeated twice; Translocation – transfer of a section of
one chromosome to non-homologous chromosome; Inversion – a
section of the chromosome becomes changed by rotation at 180
degrees
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Cri-du-chat Syndrome (5p minus syndrome)
✓ A genetic condition caused by the deletion of
genetic material on the small arm (p arm) of
chromosome 5
✓ Physical manifestations: mentally retarded,
has abnormal development of glottis and
larynx resulting from a crying sounds that
sound like the meowing of a cat.
Figure 8: Child with Cri-duchat Syndrome (file retrieved
from Google marked as “labeled
for reuse”)
Remember
A change (even a very slight change) in the number or structures of
chromosomes can drastically change the traits of an organism and can cause serious
disorders, diseases, or abnormalities.
…
Activity Time:
Part I:
Directions: Match Column A to Column B
GENETIC DISORDERS
1. Down Syndrome (Trisomy 21)
2. Cri-du-chat Syndrome (5p
minus syndrome)
3. Edward Syndrome (Trisomy
18)
4. Patau Syndrome (Trisomy 13)
5. Trisomy X Syndrome (47, XXX)
6. Klinefelter Syndrome (47,
XXY)
Malfunction of cell during the process of cell cycle
A. The condition resulting from two or more X
chromosomes in males
B. The condition that affects only female as a result of
one of the X chromosomes (sex chromosome) is missing
or partially missing.
C. Wherein the 21st chromosome has three instead of
two chromosomes.
D. Characterized by the presence of extra X
chromosome in each cell of a female
E. Caused by having an additional copy of chromosome
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7. Turner Syndrome (45, XO)
13 in some or all of the body’s cells.
F. Caused by having additional copy of chromosome 18
G. A genetic condition caused by the deletion of
genetic material on the small arm (p arm) of
chromosome 5
Part II: Essay:
Directions: Write a short essay in your notebook. You will be graded based on
the rubrics provided below.
8-10. Infer on the importance of cell cycle regulation to the normal functioning
of the body through an essay.
Rubrics:
Content----------- 2 Points
Organization---- 1 Point
_________________
Totals:
3 points
III. What I Have Learned
EVALUATION/POST-TEST:
MULTIPLE CHOICE: In your notebook, write the letter of the correct answer.
1. During the cell cycle, when are chromosomes available?
a. Only during interphase
c. Only during cell division
b. Only when they are being replicated
d. Only during the G1 phase
2. Which of the following is a correct statement about the events of the cell cycle?
a. Little happens during G1 and G2 phases
b. DNA replicates during cytokinesis
c. The M phase is usually the longest phase
d. Interphase consists of the G1, S and G2 phase
3. In what phase does a cell’s DNA replicate?
a. G1 phase
c. S phase
b. G2 phase
d. M phase
4. Which checkpoint ensures that growth factors are available?
a. M checkpoint
C. S checkpoint
b. G1 checkpoint
D. G2 checkpoint
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5. Which chromosomal abnormality is characterized by having 3 pairs of 21st chromosome
instead of 2?
a. Triple X syndrome
c. Klinefelter syndrome
b. Turrner syndrome
d. Down syndrome
6. During which phase in the cell cycle does mitosis happen?
a. G1 phase
c. M phase
b. G2 phase
d. S phase
7. Which pair includes a phase of the cell cycle and a cellular process that occurs during that
phase?
a. G1 phase – DNA replication
c. S phase – cell division
b. G2 phase – preparation for mitosis d. M phase – cell growth
9. During the cell cycle, when does a cell’s DNA
replicate?
a. G1 phase
c. S phase
b. G2 phase
d. M phase
10. Which of the following is a correct statement about the
events of the cell cycle?
a. Little happens during G1 and G2 phases
b. DNA replicates during cytokinesis
c. The M phase is usually the longest phase
d. Interphase consists of the G1, S, and G2 phases
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REFERENCES
Morales-Ramos, Anna Cherylle, and John Donnie A. Ramos. (2017).
Exploring Life Through Science Series. Quezon City: Phoenix
Publishing House, Inc.
Navarette, Bonifacio V. Jr. and Sheila Marie A. Ochoco.
(2012). Discover Science Biology. Makati City: Diwa
Learning Systems Inc.
Images for reference taken from:
https://www.google.com/search?q=turner+syndrome&tbm=ish&hl=en&t
bs&bih=566&bw=360&prmd=inv&hl=en&ved=2ahUKEwiCkPfwlqbqAhWIG
-wKHQETBOgQ3J8EegQIARAH#imgrc=0bnXbt7hf5emoM
https://www.publicdomainpictures.net/en/viewimage.php?image=156019&picture=child-with-down-syndrome
https://www.google.com?search?q=klinefelter+syndrome&tbm=isch&tbs
=sur:fc&hl=en&ved=2ahUKEwi@teGC2KbqAhXPuKQKHVNzDfEQ3J8EegQI
ARAH&biw=360&bih=342#imgrc=gT0aYzJWn2E3aM
https://www.google.com/search?q=trisomy+x&tbm=isch&ved=2ahUKEwi
BKeG2KbqAhVQNuwKHYfsCQAQ2cCegQIABAC&oq=trisomy+&gs_lcp=C
hJtb2JpbGUtZ3dzLXdpei1pbWcQARgDMgQIABBDMgQIABBDMgQIABBD
MgQIABBDMgQIABBDOgcIIxDqAhAnOgQIIxAnULKAB1iulgdgjqAHaAJwAH
gAgAH1BIgBgRuSAQczLTMuNC4xmAEAoAEBsAEF&sclient=mobile-gws-wiz
https://www.google.com/search?q=patau+syndrome&tbm=isch&hl=en&
tbs&hl=en&ved=2ahUKEwjAo47p2KbqAhVUgaQKHe57CGsQ3J8EegQIAR
AH&biw=360&bih=566#imgrc=zEZL7z3Mxwx8aM
https://www.google.com/search?q=edwards+syndrome&tbm=isch&hl=e
n&tbs&bih=566&biw=360&hl=en&ved=2ahUKEwjckbur2abqAhXkwAIHHZy
eDQwQ3J8EegQIARAH#imgrc=8wPEf6xKzYlXvM
https://www.google.com/search?q=cri+du+chat+syndrome&tbm=isch&
hl=en&tbs=sur:fc&hl=en&ved=2ahUKEwjm6qCM2qbqAhUH3KQKHdoDDAQ3J8EegQIARAH&biw=360&bih=566
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DEPARTMENT OF EDUCATION
SCHOOLS DIVISION OF NEGROS ORIENTAL
SENEN PRISCILLO P. PAULIN, CESO V
Schools Division Superintendent
FAY C. LUAREZ, TM, Ed.D., Ph.D.
OIC - Assistant Schools Division Superintendent
Acting CID Chief
NILITA L. RAGAY, Ed.D.
OIC - Assistant Schools Division Superintendent
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)
PABLO ACIERTO RAGAY JR.
Writers
PABLO ACIERTO RAGAY JR.
Illustrator
ZENLI ROSE B. MONGCUPA
NOELYN E. SIAPNO
Lay-out Artists
________________________________
BETA QA TEAM
ZENAIDA A. ACADEMIA
DORIN FAYE. D. CADAYDAY
MERCY G. DAGOY
MARIA SALOME B. GOMEZ
RANJEL D. ESTIMAR
ARJIE T. PALUMPA
LIEZEL A. AGOR
THOMAS JOGIE U. TOLEDO
ALPHA QA TEAM
LIEZEL A. AGOR
EUFRATES G. ANSOK JR.
JOAN Y. BUBULI
MA. OFELIA I. BUSCATO
LIELIN A. DE LA ZERNA
THOMAS JOGIE U TOLEDO
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
This self-learning kit is designed to help
learners understand the concept of cell
cycle and its control points; including topic
on disorders and diseases that result from the
malfunction of the cell during the cell cycle - in a simple, engaging, and concise manner
possible, contextualized to meet the
standards of the K to 12 curriculum thereby
facilitating optimum learning.
Learners are then expected to
accomplish the objective set at the start of
the lesson about cell cycle. Moreover, the
author hopes that this module will increase
learners’ engagement, help them retain and
remember information easily, and deepen
their understanding of the concept through
hands-on and application-based learning
opportunities provided in this module.
As they proceed and be engaged in
this simple module, may they remember to
internalize these concepts and be prepared
to apply these things in the future.
ABOUT THE AUTHOR
PABLO ACIERTO RAGAY JR. finished his course at
Negros Oriental State University with a degree of
Bachelor in Secondary Education major in
Biological Science last 2015. He is a Grade 12
teacher/adviser at Caticugan High School in the
senior high school (SHS) department, a SHS school
focal person, and at the same time the acting SHS
registrar. He is currently taking Master of Arts in
Science Teaching at Negros Oriental State
University.
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