GENERAL BIOLOGY 2 FOR SENIOR HIGH SCHOOL

1. ATP AND COUPLED
REACTION PROCESSES
for General Biology 1 Grade 11
Quarter 2 / Week 1

2. 2
FOREWORD
This self-learning kit (SLK) is an instructional material
created to serve as guide for learners in understanding
the concepts of ATP and coupled reaction processes.
The activities and illustrations contained in this learning
material are carefully planned and designed to provide
thorough understanding of the lesson.
Furthermore the second part of this SLK aims to develop
among learners the understanding of the importance of
chlorophyll and other pigments particularly in the process
of food production. The activities and illustrations
contained in this learning material are carefully planned
and designed to provide thorough understanding of the
lesson and to stimulate cognitive skills among learners.

3. 3
LEARNING COMPETENCY:
Explain coupled reaction processes and describe the
role of ATP in energy coupling and transfer
(STEM_BIO11/12-IIa-j-1)
I. WHAT HAPPENED
OBJECTIVES:
K: Explain coupled reaction processes and the role of ATP
S: Create an ATP model and diagram of an ATP-ADP cycle
A: Recognize the important role of ATP in carrying out essential life
processes
Ana: Hi, fellow STEM-mates! We are
back again.
It’s a brand new day. We are here to
guide and help you understand
another lesson.
Roy: How are you all doing
today?
Are you excited?
That’s great! Have fun and
enjoy the lesson and activities!
LESSON
1
ATP AND THE DIFFERENT COUPLED
REACTION PROCESSES

4. 4
PRE-ACTIVITY:
Situation: Suppose you have two rechargeable batteries.
One is fully charged and the other one is almost empty. You
inserted each battery in each of the two flashlights. Predict
what will happen to the light emitted in the two flashlights.
Draw your prediction in the box provided.
1. Compare the light emitted in image A and image B.
Image A:
_________________________________________
Image B:
_________________________________________
2. What could be the reason why the two flashlights differ
in light emission?
ACTIVITY 1
A B

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3. What is stored in the battery which enables the
flashlight to emit light?
4. How can the light emitted in the two flashlights be the
same?
II. WHAT I NEED TO KNOW
DISCUSSION:
Energy is essential to life. All living things must be able to
produce energy, store energy for future use, and use energy
to carry out life processes. In everyday life, energy is
important because it can be used to do work such as
eating, walking, running, talking, and thinking or simply
turning the pages of this learning material. Some cellular
activities that require energy are active transport, protein
synthesis, and cell division. Energy can exist or be stored in
The pre-activity given to you is an
analogy of the lesson that we are about
to tackle today.
Can you still recall what ATP is?
What are its functions in cellular
processes?
Why is energy essential to life?
Kindly read carefully the next
pages and recall your prior
knowledge about ATP to answer
the questions and to better
understand the lesson.

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many forms such as light, heat, electricity, and chemical
bonds in chemical compounds.
ATP Structure and Hydrolysis
How do organisms carry out essential life processes?
Cells in organisms obtain energy from the chemical bonds
that hold together certain organic compounds, such as
carbohydrates from the food that we eat. This energy in turn
is used to produce adenosine triphosphate (ATP). ATP is an
organic molecule used for short-term energy storage and
transport in the cell. It is composed of three parts: (1) a
nitrogenous base (adenine), a sugar (ribose), and three
phosphate groups (triphosphate) (Figure 1).
Figure 1. Structure of an ATP molecule.
Source: ©2014 Nature Education. All rights reserved.
The three phosphate groups in an ATP molecule are
negatively charged. Recall that molecules having the same
charge will tend to repel from each other. Thus, this means
that the three phosphate groups are in an unstable
arrangement. The third phosphate group is so eager to get
further away from the two phosphate groups. A bond
between them is broken through hydrolysis (water-mediated

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breakdown) reaction releasing energy (Figure 2). The
remaining free phosphate group and low-energy molecule is
called adenosine diphosphate (ADP).
Pi stands for an inorganic phosphate group .
ATP is hydrolyzed in the following reaction:
Figure 2. Hydrolysis of ATP to ADP.
Source: ©2013 Nature Education. All rights reserved.
ATP-ADP Cycle
The hydrolysis of ATP to ADP is reversible. ATP and ADP
are like charged and uncharged forms of a rechargeable
battery. ATP (charged battery) has energy that can be used
to power cellular processes or reactions. Once the energy is
used up, ADP (uncharged battery/dead battery) needs to
be recharged in order to be used as a power source.
ATP regeneration reaction is the reverse of hydrolysis
reaction:

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Figure 3. ATP-ADP cycle. Source: quizlet.com
Remember
• When ATP is broken down, energy is released
and ADP is formed.
• When ADP binds with another phosphate
group, energy is stored and ATP is formed.
ATP in Energy Coupling
How is the energy released by ATP hydrolysis used to
power cells to carry out useful functions? The hydrolysis of
ATP not only results to a release of energy but also would
simply result in organisms’ overheating because the
dissipation of energy would excite nearby molecules,
resulting in heat or thermal energy. Energy in a cell needs to
be linked to other processes in order to be useful. Energy
coupling is the transfer of energy from one chemical
reaction to another. An energetically favorable reaction
(exergonic, e.g., ATP hydrolysis) is directly linked with an
energetically unfavorable reaction (endergonic, e.g., ATP
regeneration). Through energy coupling, the cell can
perform nearly all of the tasks it needs to function.

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Chemical reactions can be classified as either
exergonic (energy outward) or endergonic (energy inward)
(Figure 4):
• Exergonic reaction - proceeds with a net release
of free
• energy
• Endergonic reaction - one that absorbs free
energy from its
surroundings
Figure 4. Exergonic and endergonic reactions.
Source: https://chem.libretexts.org
One example of energy coupling involving ATP is the
formation of sucrose (table sugar) from glucose and fructose
(Figure 4). In the uncoupled reaction, glucose and fructose
combine to form sucrose. In the coupled reaction, there are
two reactions that take place:
1. A phosphate group is transferred from ATP to
glucose, forming a phosphorylated glucose
intermediate (glucose-P). This is an energetically
favorable reaction or exergonic reaction.
2. The glucose-P intermediate reacts with fructose to
form sucrose. Because glucose-P is relatively

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unstable, this reaction also releases energy and is
spontaneous.
Figure 4. Formation of sucrose (table sugar) from
glucose and fructose (uncoupled and coupled
reactions). Source: khanAcademy.org
The strategy in the example above is used in many
metabolic pathways in the cell, providing a way for the
energy released through ATP to ADP conversion to drive
other reactions forward.
A. Connect Me. Draw bonds to connect the following image
in order to show an ATP model. Identify and label the three
parts of an ATP molecule, and place an asterisk (*) on the
bond that stores the most energy. Write your answer on a
separate sheet of paper.
ACTIVITY 2
1. 2. 3.

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B. Create Me. Make a diagram showing an ATP-ADP
cycle.

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III.WHAT HAVE I LEARNED
EVALUATION/POST-TEST:
Modified True or False. Indicate whether the
statement is True or False. If false, change the
underlined word(s) to make the statement correct.
___________1. The main chemical compound
used by cells for energy is
adenosine diphosphate (ADP).
___________2. The ribose of ATP is the key to its
ability to store and supply
energy.
Good job! You have learned already on how organisms carry out
essential life processes in the presence of ATP. This time, you will
apply the things that you have learned in the previous discussions
and activities by answering the following tasks below.
TASK A

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___________3. ATP releases energy when it
breaks bonds between its
phosphate groups.
___________4. Endergonic reaction releases
energy while exergonic reaction
absorbs energy from the
surroundings.
___________5. Energy coupling is the transfer of
energy from one chemical
reaction to another.
Answer Me. Answer the following questions briefly. (5 points)
1. What are coupled reactions?
_____________________________________________________
2. Why is ATP important in energy coupling and transfer?
_____________________________________________________
3. What are some essential life processes that are
fueled by ATP hydrolysis? Name at least three.
_____________________________________________________
TASK B

14. 14
REFERENCES
ATP-ADP cycle. images.pcmac.org
ATP and cellular work. Principles of Biology. Nature
Education, 2003. dls.ym.edu.tw
ATP and reaction coupling.
https://www.khanacademy.org/science/biology/e
nergy-and-enzymes/atp-reaction-coupling/a/atp-
and-reaction-coupling
ATP notes and putting it all together.
www.henshudschools.org
Campbell, Neil A., Reece, Jane B. , Lisa A., Urry,
Cain, Michael L., Wasserman, Steven A., Minorsky,
Peter V., and Jackson, Robert B. Biology, 8th Edition.
Pearson Education, Inc.: San Francisco, 2008
Chapter 8.1: energy and life. www. wlwv.k12.or.us
Coupled reactions
https://chem.libretexts.org/Courses/Mount_Royal_Uni
versity/Chem_1202/Unit_7%3A_Principles_of_Thermod
ynamics/7.7%3A_Coupled_Reactions
Worksheet: chemical energy and ATP, Biology.
www.frontiercsd.org

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ABOUT THE ILLUSTRATOR
ABOUT THE AUTHOR
LIEZEL A. AGOR is a graduate of Bachelor of Science in
Biology, cum laude, at Negros Oriental State University, Main
Campus I, Dumaguete City in 2011. She was a recipient of
the DOST-SEI scholarship grant under R.A. 7687. She earned
units in education in the same school through Continuing
Professional Education (CPE) program in 2016. At present,
she is a Special Science Teacher I handling Grade 11
students at Siaton National High School and at the same
time an adviser and Senior High School Science coordinator.
MARY JEAN M. ARBOLADO is an alumna of Sumaliring High
School, batch 2018. She took up Accountancy, Business, and
Management (ABM) strand in the said school and is an NCIII
holder in Bookkeeping. She is currently enrolled as a second
year student taking up Bachelor of Science in Secondary
Education Major in Social Studies at Negros Oriental State
University, Siaton Campus.
SYNOPSIS
This self-learning kit contains
discussions
and activities based on the comp
etency
“Explain coupled reaction
processes and describe the role of
ATP in energy coupling and
transfer” in General Biology 1.
Learners are expected to ac
complish the learning objectives
and understand the concepts of
ATP and coupled reaction
processes, encouraged to
analyze problems critically, and
be able to relate the lesson to
real-life scenarios.

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LEARNING COMPETENCY:
Explain the importance of chlorophyll and other
pigments (STEM_BIO11/12-IIa-j-3)
I. WHAT HAPPENED
LESSON
2
THE IMPORTANCE OF CHLOROPHYLL
AND OTHER PIGMENTS
OBJECTIVES:
At the end of the lesson, the learners shall be able to:
K: Explain the importance of chlorophyll and other pigments
S: Identify plant pigments according to the wavelength of light
absorbed
A: Demonstrate understanding on the important role of chlorophyll
and other pigments in initiating photosynthesis in plants
Good morning, dear STEM students!
How are you today?
Welcome to our new and exciting
lesson. I will be your guide in
learning about plant pigments.
Are you ready?
So, let’s get started!

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PRE-ACTIVITY:
Identify My Color. Observe the three kinds of leaves and
answer the guide questions that follow. Write your answers
on a separate sheet of paper.
Source: SteemKR.com Source: ravallirepublic.com
Source: FishLab.com
Guide Questions:
1. How are the leaves different from each other?
2. In what ways are their colors different?
Malunggay leaves:______________
Mayana leaves:_________________
Talisay leaves:___________________
3. Why do you think plant leaves have different color?
Malunggay leaves Mayana leaves Talisay leaves
ACTIVITY 1

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II. WHAT I NEED TO KNOW
DISCUSSION:
Light from the sun is absorbed by colorful compounds
called pigments. The structure and amount of pigments
determine the variations in color. The chlorophyll pigment in
leaves helps make photosynthesis happen by absorbing light
energy from the sun to put together carbon dioxide and
water to form glucose or food. All colors of visible light
except green are absorbed by chlorophyll, which it reflects
to be detected by our eyes. Chlorophyll gives plants their
green color and may hide the other pigments found in
leaves. If all colors or wavelengths of visible light are
absorbed and none are reflected, the pigment appears
black to our eyes. On the contrary, if all colors or
wavelengths of light are reflected, the pigment appears
white to our eyes.
Now that you have identified the
colors of the given plant leaves,
can you define what pigments are?
What are the types of pigments?
To answer these questions, kindly
read and understand carefully the
proceeding discussion.
Have fun and enjoy!

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3
Figure 1. The visible light spectrum. Source:
thoughtco.com
Chlorophylls appear green
because the pigments absorb
light on all of the color ranges,
and only green is transmitted to
our eyes. Chlorophyll a is the
core pigment that absorbs
sunlight for light-dependent
photosynthesis. It readily absorbs
violet/blue and red light but not
much of the lighter blue, and
green and yellow light. It looks
bluish green.
Chlorophyll and Accessory Pigments
Green plants have green leaves, and the leaves are green
because of the green pigment called chlorophyll, which are found in
the chloroplasts. The visible light spectrum ranges from red (the longest
wavelength) to orange, yellow, green, blue, indigo, and violet (the
shortest wavelength). Plants possess pigments that can absorb light in
specific regions of the spectrum.
Figure 2. Absorbance spectrum of plant
pigments. Source: webprojects.oit.ncsu.edu

20. 20
Leaves have evolved to produce several other pigments
called accessory pigments. Accessory pigments absorb
wavelengths of light that chlorophyll cannot absorb effectively,
enabling the plant to use more of the sun’s energy (Figures 2 and
3).
The following are the types of accessory pigments:
1. Chlorophyll b – It is structurally only slightly different from
chlorophyll a but its absorption spectrum is somewhat
different. It absorbs more in the blue and orange-red
ranges. It looks yellowish green. Captured energy is
handed over to chlorophyll a, which is a smaller but
more plentiful molecule in the chloroplast.
2. Carotenoids – They absorb light from violet to the
greenish-blue range. They appear in various shades of
yellow or yellow-orange to our eyes. They cluster next to
chlorophyll a molecules to efficiently hand off
absorbed photons. They are usually found attached to
proteins or membranes in the chloroplasts.
3. Anthocyanins – They do not participate in
photosynthesis and may appear red, purple, or blue.
They occur widely among higher plants. They are
pigments that generally give color to flowers but also
occur in leaves and fruits. In leaves, these pigments
often help to protect against excessive sunlight that
can damage some leaf tissues. This is one reason why a
young, newly developing leaf is often redder than
when it reaches its mature size.
4. Xanthophylls – They pass along light energy to
chlorophyll a and act as antioxidants. The molecular
structure gives xanthophylls the ability to accept or
donate electrons. Xanthophyll pigments produce the
yellow color in fall leaves.

21. 21
Where do the pigments occur in plants?
The leaves of plants have mesophyll cells, the
photosynthetic cells. These cells possess specialized
structures called chloroplasts where photosynthetic pigments
are located (Figure 4). Other pigments that are not involved
in photosynthesis are stored in the vacuole, a large cellular
structure that also serves as storage place of water and
nutrients.
The presence of accessory pigments explains why not
all leaves are green (Figure 5). Accessory pigments are
important since they help absorb light and then pass the
energy to chlorophyll a, a primary pigment.
Figure 3. Representation of energy
transfer by antenna pigments.
Source: https://ib.bioninja.com.au
Figure 5. Varying pigments in leaves.
Source: tomatosphere.letstalkscience.ca

22. 22
Figure 4. Location of pigments in plants.
Source: w3.marietta.edu
Match Me. Match the terms in column A to the
descriptions in column B. Write the letter of your
answer on the space provided before each item.
a. The primary pigment that absorbs
sunlight for light-dependent
photosynthesis.
b. The pigment responsible for bright
red, yellow, and orange hues in
many fruits and vegetables.
c. This pigment plays a role in
attracting pollinators and protects
plant tissues against abiotic
stressors.
d. It has a yellow pigment that
occurs widely in nature.
e. It absorbs blue light and expands
the absorption spectrum of
organisms.
_______1. Xanthophyll
_______2. Chlorophyll b
_______3. Anthocyanins
_______4. Chlorophyll a
_______5. Carotenoids
ACTIVITY 2

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III. WHAT HAVE I LEARNED
EVALUATION/POST-TEST:
Complete Me. Complete the statements below by supplying
the correct answer on the space provided in each item.
1. The principal pigment in plants that captures light energy is
________.
2. The wavelengths of light absorbed by chlorophyll a are
________.
3. The wavelengths of light absorbed by
carotenoids are __________.
4. The wavelength of light that chlorophyll a reflects is
____________.
5. The light-absorbing pigments, such as chlorophyll and
carotenoids, are located in the _______.
Great job, dear STEM students!
You have familiarized already
the different types of pigments
and learned their roles and
functions. This time, let’s check
whether you have fully
understood the lesson by
doing the next tasks.
Good luck!
TASK A

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Expand and Explain. Read and understand each
question carefully. Write your answers on a separate
sheet of paper.
1. Why are chlorophyll and other pigments important in
plants?
___________________________________________________________
___________________________________________________________
2. How are pigments related to photosynthesis in plants?
___________________________________________________________
___________________________________________________________
TASK B

25. 25
REFERENCES
Campbell, Neil A., Reece, Jane B. , Lisa A., Urry,
Cain, Michael L., Wasserman, Steven A., Minorsky,
Peter V., and Jackson, Robert B. Biology, 8th Edition.
Pearson Education, Inc.: San Francisco, 2008
Energy transformation and photosynthesis. Biology,
chapter 8. www.northallegheny.org
Leaf structure and pigments. w3.marietta.edu
Morales-Ramos AC, Ramos JD. Exploring life through
science series. Senior High School, General Biology I.
Phoenix Publishing House: Quezon City, Metro
Manila, 2017
Pigments.
http://www.biology.arizona.edu/biochemistry/probl
em_sets/intro_photosynthesis/pigments.html

26. 26
ABOUT THE AUTHOR
SYNOPSIS
This self-learning kit contains
discussions
and activities based on the compete
ncy
“Explain the importance of
chlorophyll and other pigments” in
General Biology 1.
Learners are expected to gain
more knowledge about chlorophyll
and other plant pigments, learn that
some of these pigments found in
plant leaves are vital for
photosynthesis, and demonstrate
understanding on the certain
wavelengths of light they absorb.
LIEZEL A. AGOR is a graduate of Bachelor of Science in Biology,
cum laude, at Negros Oriental State University, Main Campus I,
Dumaguete City in 2011. She was a recipient of the DOST-SEI
scholarship grant under R.A. 7687. She earned units in
education in the same school through Continuing Professional
Education (CPE) program in 2016. At present, she is a Special
Science Teacher I handling Grade 11 students at Siaton
National High School and at the same time an adviser and
Senior High School Science coordinator.

27. 27
DEPARTMENT OF EDUCATION
SCHOOLS DIVISION OF NEGROS ORIENTAL
SENEN PRISCILLO P. PAULIN, CESO V
Schools Division Superintendent
FAY C. LUAREZ, TM, EdD, PhD
OIC - Assistant Schools Division Superintendent
Acting CID Chief
NILITA L. RAGAY, EdD
OIC - Assistant Schools Division Superintendent
ARNOLD R. JUNGCO
EPS-Science/Math
ROSELA R. ABIERA
LR Manager
ELMAR L. CABRERA
PDO
MARICEL S. RASID
Librarian
LIEZEL A. AGOR
Writer
MARY JEAN M. ARBOLADO
Illustrator
KOREN O. BALBUENA
Lay-out Artist
______________________________________________
ALPHA QA TEAM
LIELIN A. DE LA ZERNA
MA. OFELIA I. BUSCATO
THOMAS JOGIE U. TOLEDO
EUFRATES G. ANSOK JR.
LIEZEL A. AGOR
JOAN Y. BUBULI
BETA QA TEAM
JUSTIN PAUL ARSENIO C. KINAMOT
PETER PAUL A. PATRON
THOMAS JOGIE TOLEDO
MARY JOYCEN A. ALAM-ALAM
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.