This is the Alternative Delivery Mode (ADM) self-learning module for Physical Science, Grade 12, Quarter 1, Module 4: The Chemistry of Life (Biomolecules). It is meant for Non-STEM Senior High School students who take Physical Science as a core subject, and teachers can also use it for remediation. After working through it, learners should be able to identify, describe, and explain the four biomolecules: carbohydrates, lipids, nucleic acids, and proteins.
On this page 6 sections
What learners will learn
The module states the learning competency: explain how the structures of biological macromolecules, such as carbohydrates, lipids, nucleic acids, and proteins, determine their properties and functions (S11/12PS-IIIe-22).
After going through the module, learners are expected to:
- Identify the four macromolecules according to their general structure.
- Describe the properties of each macromolecule.
- Explain the functions of each macromolecule, and the common samples where each can be found.
Lesson in this module
The module has one lesson, Lesson 1: The Chemistry of Life. It explains that living organisms are mostly made of organic compounds, which are built through a process called biosynthesis. It then describes the structure, function, and everyday examples of each of the four biomolecules.
Key ideas: the four biomolecules
Biomolecules, also called macromolecules, are large organic molecules that make up all living organisms. Organic compounds are carbon-rich molecules, usually combined with hydrogen and oxygen.
Carbohydrates
Carbohydrates are among the most abundant macromolecules on Earth. The name means “hydrates of carbon” because the simplest formula has a 1:2:1 ratio of carbon, hydrogen, and oxygen, as in glucose (C6H12O6). A more general formula is Cm(H2O)n, where m is 3 or more, as in sucrose or table sugar (C12H22O11).
| Simple carbohydrates | Complex carbohydrates | |
|---|---|---|
| Structure | Small, usually 1 to 2 sugar molecules | Long chains of simple sugars bonded together |
| Digestion | Easy and quick to digest | Takes longer to break down |
| Main function | Quick, “instant” energy | Structural material and energy storage that lasts longer |
| Examples | Glucose, table sugar | Chitin (exoskeleton), cellulose (plant cell wall), starch, glycogen |
Lipids
Lipids do not dissolve in water but dissolve in nonpolar or low-polarity solvents. They have three main jobs: storing energy (especially in animals), forming part of cell membranes, and acting as chemical messengers in the body.
Fats and oils, or triglycerides, are made of long-chain fatty acids bonded to glycerol. Fatty acids can be:
- Unsaturated: at least one pair of double-bonded carbons, liquid at room temperature, usually from plants.
- Saturated: no double bonds, solid at room temperature, found in animal fats.
Trans fats are artificially hydrogenated oils. Adding hydrogen saturates the oil, making it more stable and helping food last longer on the shelf.
Nucleic acids
Nucleic acids store genetic information and are key to the continuity of life. They are made of nucleotides, and each nucleotide has a pentose (5-carbon) sugar, a phosphate group, and a nitrogenous base.
| Feature | DNA | RNA |
|---|---|---|
| Strands | Double-stranded, helical | Single-stranded |
| Bases | Adenine, guanine, cytosine, thymine | Adenine, guanine, cytosine, uracil |
| Sugar | Deoxyribose | Ribose |
| Function | Carries genetic make-up | Protein synthesis |
Proteins
Proteins are among the most complex macromolecules. Their building blocks are amino acids, and 20 are known. Each amino acid has an amino group, a carboxylic group, and an R group (side chain); the side chain makes each amino acid unique. The module groups proteins by function:
- Structural: keratin in hair
- Regulatory: hormones such as insulin
- Contractile (movement): actin and myosin
- Protective: antibodies made by white blood cells
- Transport: hemoglobin, which carries oxygen
- Storage: egg albumin, which nourishes a developing embryo
How to use this module
The module asks learners to answer the pretest (What I Know) before reading, then read the lesson and do the activities. Grading is based on the post-test (Assessment). The parts are:
- What I Know: a 15-item multiple-choice pretest.
- Activity 1: identify whether pictured samples (hair, brown sugar, DNA, butter, a candle) are made of carbohydrates, lipids, nucleic acids, or proteins.
- What is It: the lesson discussion.
- Activities 1.1 to 1.3: draw and label glucose, cholesterol, alanine, and DNA; describe each biomolecule in two sentences; and classify hemoglobin, RNA, plant fiber, and margarine with their functions.
- What I Have Learned: a five-item fill-in-the-blanks review.
- What I Can Do: give product examples of each biomolecule in health sciences and in industry.
- Assessment: a 15-item multiple-choice post-test.
- Additional Activities: watch the video “Biological molecules – You are what you eat” and reflect on it using a four-square analysis.
Learners: write your answers on a separate sheet of paper, and check the answer key only after finishing each test. Parents: you can help by making sure the pretest is done before the reading. Teachers: the answer key covers the pretest, What I Have Learned, and the Assessment; the drawing, description, and reflection activities need your own checking.
Frequently asked questions
What grade and quarter is this Physical Science module for?
The module is labeled Physical Science Grade 12, Quarter 1, Module 4. It is intended for Non-STEM Senior High School students taking Physical Science as a core subject.
What are the four biomolecules covered in the module?
Carbohydrates, lipids, nucleic acids, and proteins. The module explains the general structure, properties, functions, and common examples of each.
Does the module have an answer key?
Yes. It gives answers for the pretest (What I Know), the What I Have Learned fill-in-the-blanks, and the 15-item Assessment.
What is the difference between saturated and unsaturated fats?
Unsaturated fats have at least one pair of double-bonded carbons, are liquid at room temperature, and usually come from plants. Saturated fats have no double bonds, are solid at room temperature, and are found in animal fats.
What is the difference between DNA and RNA?
DNA is double-stranded and helical, uses deoxyribose sugar and the base thymine, and carries genetic make-up. RNA is single-stranded, uses ribose sugar and the base uracil, and is used for protein synthesis.
Full text of the module
The text below is a transcription of the PDF above, as printed.
Physical Science Quarter 1 – Module 4: The Chemistry of Life (Biomolecules)
Senior High School
[illustration: students reading and writing outdoors and indoors, a teacher at a desk, and students with a globe and a lamp]
Department of Education • Republic of the Philippines
Physical Science – Grade 12 Alternative Delivery Mode Quarter 1 – Module 4: The Chemistry of Life (Biomolecules) First Edition, 2020
Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this book are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them.
Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio
Development Team of the Module
Author: Suzzeth U. Dizon Editors: Joey H. Villanueva, Arlene C. Malaybalay Reviewers: Tommy R. Rico, Emiterio D. Macarubbo, Maricris N. Surigao Illustrator: Helen Grace L. Cabalag Layout Artist: Justine C. Montoya Management Team: Wilfredo E. Cabral, Director IV Jennifer Vivas, CLMD Chief Dennis M. Mendoza, Regional EPS in-charge of LRMS Micah S. Pacheco, Regional ADM Coordinator Jocelyn M. Aliñab, CID Chief Tommy R. Rico, Division in-charge of LRMS and Division ADM Coordinator
Department of Education – National Capital Region
Office Address: Misamis St., Bago Bantay, Quezon City Telefax: 02-929-0153 E-mail Address: depedncr@deped.gov.ph
Physical Science
Quarter 1 – Module 4: THE CHEMISTRY OF LIFE (BIOMOLECULES)
This instructional material was collaboratively developed and reviewed by educators from public and private schools, colleges, and or/universities. We encourage teachers and other education stakeholders to email their feedback, comments, and recommendations to the Department of Education at action@deped.gov.ph.
We value your feedback and recommendations.
Department of Education • Republic of the Philippines
Introductory Message
For the facilitator:
This module is intended for the Non-STEM Senior High School Students taking up Physical Science as their core subject. This may serve as remediation for learners as well as a form of Alternative Delivery Mode of Learning Resources, in times of need.
For the learner:
The module is an interactive learning material. Answer pre-test prior to the reading of the information followed by answering the activities. Your learning assessment will be based on the post test.
What I Need to Know
This module was created to help and give you an idea of the concepts behind the four macromolecules: carbohydrates, lipids, nucleic acids, and proteins. Since these molecules primarily constitute a living organism, they are also called biomolecules.
The module will focus on discussing the general structure and functions of biomolecules, as well as the common samples or material where they could be seen.
The learners are also expected to:
(a) explain how the structures of biological macromolecules, such as carbohydrates, lipids, nucleic acid, and proteins, determine their properties and functions (S11/12PS-IIIe-22)
After going through this module, you are expected to:
- Identify the four macromolecules according to their general structure;
- Describe the properties of each macromolecule; and
- Explain the functions of each macromolecule, as well as the common samples where it can be seen.
What I Know
Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper.
Which biomolecule has a biological function as a first-line source of energy’?
- A. Carbohydrates
- B. Lipids
- C. Nucleic Acids
- D. Proteins
Which represents a carbohydrate?
- A. CnH2n+2
- B. (CH2O)n
- C. CnH2n
- D. (C2HO)n
The following samples are simple carbohydrates except _______.
- A. Cellulose
- B. Fructose
- C. Glucose
- D. Sucrose
Which statement below best describes a lipid?
- A. It is insoluble in water.
- B. It is always in gaseous form.
- C. Its general structure is only made up of carbon and hydrogen.
- D. It can form ionic compounds due to its ability to become ionic.
Which structure below is rich in lipid as manifested by its function?
- A. Human muscle fibers
- B. Rigid cell wall of plant cells
- C. Semi-permeable cell membrane
- D. Enzymes catalyzing substances
Which one is NOT a lipid?
- A. Cholesterol
- B. Lactase
- C. Triglyceride
- D. Waxes
What is primarily the function of a nucleic acid?
- A. As storage of energy of the body
- B. As an energy source of the body
- C. As structural molecules of most living organisms
- D. For storage and expression of genetic information
What does DNA mean?
- A. Dinucleotide adenine
- B. Dinucleic adenine
- C. Deoxyribonucleic acid
- D. Diribonucleic acid
Which of the molecules below DOES NOT constitute a nucleic acid?
- A. Amino acid
- B. Nitrogenous base
- C. Phosphate group
- D. Sugar
For nos. 10-11, refer to the figure below:
[illustration: ball-and-stick model of an amino acid molecule showing an amino group (N with H atoms), a central carbon with H and a box labeled R, and a carboxyl group (C with two O atoms and one H)]
Figure 1 – Amino acid molecule (https://en.wikipedia.org/wiki/Amino_acid#/media/File:AminoAcidball.svg)
What group is attached to the left side of the central Carbon?
- A. Amino group
- B. Hydrogen group
- C. Acid group
- D. Side Chains/Functional Groups
What makes an amino acid unique from one other?
- A. The form of attachment
- B. The different side chains
- C. The manner of peptide bonding
- D. The presence of acids and bases
Which is rich in protein?
- A. Plant leaves
- B. Human hair
- C. Vegetable oil
- D. Table salt
For nos. 13-15, choices are:
- A. Carbohydrate
- B. Lipid
- C. Nucleic Acid
- D. Protein
Which constitutes a plant fiber?
Which is a component of grease?
Which has amino acids as its building blocks?
Lesson 1: THE CHEMISTRY OF LIFE
Living organisms are primarily made up of organic compounds. The process of building organic molecules by living organisms is called biosynthesis.
What’s In
Biomolecules (also known as macromolecules) are organic compounds that make up all living organisms. They are all produced through the process of biosynthesis. As previously discussed, organic compounds are carbon-rich molecules usually in association with hydrogen and oxygen. Organic and nature-based materials that we use today are primarily rich in these four macromolecules. The four macromolecules are carbohydrates, lipids, nucleic acids, and proteins.
What’s New
Activity 1
The objective of this activity is to determine how familiar you are with the different types of macromolecules and their examples.
Direction: Write the letter of the correct answer. Given the samples below, determine if they are made from:
- A. Carbohydrates
- C. Nucleic Acid
- B. Lipids
- D. Proteins
transcriber’s note: this page has no column headings printed; the left column holds item numbers and the right column holds pictures.
| Item | Picture |
|---|---|
| 1. | [photo: back view of a person with long reddish-brown hair] |
| 2. | [photo: sachets labeled BROWN SUGAR and white sachets in a clear container] |
| 3. | [illustration: DNA double helix model] |
| 4. | [photo: DARIGOLD Natural Salted BUTTER box beside a slice of bread spread with butter] |
| 5. | [photo: lit candle against a dark background] |
What is It
Have you ever thought about what makes up a living organism? Biologically, they are made up of cells, tissues, organs, and body systems. But if we look closely, all forms of life are considered matter, hence, made up of compounds. Molecules that make up a living organism are called biomolecules. They are also known as macromolecules as they large organic molecules.
Biomolecules are produced through a process known as biosynthesis. There are four types of biomolecules, namely: carbohydrates, lipids, nucleic acids, and proteins. Let us describe each of them, focusing on their function, importance, and practical examples.
CARBOHYDRATES
Carbohydrates are one of the most abundant macromolecules on Earth. Literally, the term means “hydrates of carbons” because of its 1:2:1 ratio of carbon, hydrogen, and oxygen of its simplest chemical formula, respectively (e. g., C6H12O6 for glucose). A more generalized formula is Cm(H2O)n, where m is equal to 3 or more, and m and n are not necessarily equal (e. g. C12H22O11 for sucrose or table sugar).
Carbohydrates are generally classified as simple or complex. Table 1 shows the difference between simple and complex carbohydrates.
Table 1 Simple and Complex Carbohydrates
| Simple Carbohydrates | Complex Carbohydrates | |
|---|---|---|
| Structure | Small, usually made up of 1-2 sugar molecules | Made up of long chains of sugar molecules; made up of simple carbohydrates covalently bonded together |
| Rate of Digestion | Easy and quick to digest | Longer time to break down |
| Primary function in relation to its structure | Provides ‘instant’ energy, commonly in so-called ‘sugar rush’ | As structural material, and as storage form — provides more lasting energy |
| Examples | glucose, table sugar | Chitin (exoskeleton) Cellulose (plant cell wall) Starch and glycogen |
LIPIDS
Lipids are a large group of substances also found in living systems. They are insoluble in water but are soluble in solvents that are nonpolar or have low polarity. Lipids have three major functions:
energy storage, especially in animal systems
structural, as part of cellular membranes
as chemical messengers that deliver signals from one part of the body to another
There are several types of lipids based on their structure but you would be more familiar with fats and oils, also known as triglycerides, or simply, “fats”. A fat molecule is composed of long-chain fatty acids bonded to glycerol. Glycerol is an organic compound with three carbons, five hydrogens, and three hydroxyl groups, while fatty acids have long chains of hydrocarbons with a carboxyl group. Can you identify these parts in Figure 1?
[chart: chemical diagram; Figure 1 Lipid molecule. Labels printed: 9, 12, 15, α, ω]
Figure 1 Lipid molecule (https://en.wikipedia.org/wiki/Lipid#/media/File:Fat_triglyceride_shorthand_formula.PNG)
Fatty acids that make up fats are either saturated or unsaturated. Fats and oils may also be classified that way. “Saturation/Unsaturation” of fats indicates the presence or absence of double bonds in the fatty acid chain. Unsaturated fats have at least one pair of double-bonded carbons, are liquid at room temperature, and are commonly extracted from plants. On the other hand, saturated fats do not have double-bonded hydrocarbons, are solid even at room temperature, and present in animal fats. You may also have heard about trans fats. These are artificially hydrogenated oils commonly used in the food industry. Hydrogenation, the addition of hydrogen to the oil structure, results in the saturation of the oil, making it more stable hence prolonging the shelf life of food.
Can you name some examples of the different kinds of lipids?
NUCLEIC ACIDS
Nucleic acids are the most important biomolecules in the continuity of life. They store genetic information in the cell, and are in the form of either DNA (deoxyribonucleic acid) or RNA (ribonucleic acid). Nucleic acids are made up of nucleotides. Nucleotides have three components: pentose sugar (5-carbon sugar), phosphate group, and nitrogenous base. Table 2 shows the features that differentiate DNA from RNA. Figure 2 shows the parts of a nucleotide.
Table 2 Features of DNA and RNA
| Features | DNA | RNA |
|---|---|---|
| Strands | Double-stranded, helical | Single-stranded |
| Nitrogenous base/s present | adenine, guanine, cytosine, thymine | adenine, guanine, cytosine, uracil |
| Sugar molecule | Deoxyribose | Ribose |
| Functions | Carries genetic make up | For protein synthesis |
[chart: labeled diagram; Figure 2 Parts of the nucleotide. Labels printed: Nitrogenous base, Phosphate, Sugar]
Figure 2 Parts of the nucleotide (https://en.wikipedia.org/wiki/Nucleotide#/media/File:0322_DNA_Nucleotides.jpg)
PROTEINS
Proteins are some of the most complex macromolecules in terms of structure and function. Like carbohydrates, proteins are also very abundant in living organisms. The building blocks of proteins are the amino acids of which 20 are known. An amino acid has an amino group, a carboxylic group, and an R group or side chain. Each amino acid has a different R group or side chain, which makes each amino acid unique. Figure 3 below shows the parts of the amino acid molecule.
[chart: labeled diagram; Figure 3 Amino Acid Structure. Labels printed: Amino Group, Carboxylic Group, Side Chain]
Figure 3 Amino Acid Structure (https://commons.wikimedia.org/wiki/File:Unionized_Alpha_Amino_Acid_Structure.svg)
The different types of proteins are classified based on their function. Keratin in the hair is an example of a structural protein, while hormones like insulin are regulatory proteins. Actin and myosin proteins are for movement, and are called
contractile proteins. Antibodies that are produced by the white blood cells are called protective proteins, while hemoglobin which carries oxygen gas is an example of a transport protein. Egg albumin is a storage protein that serves as nourishment for the developing embryo.
What’s More
Activity 1.1 Draw me
Draw the structure of the indicated example of biomolecules. Label the parts of the molecule.
| Biomolecule Examples | Structure |
|---|---|
| 1. Glucose | |
| 2. Cholesterol | |
| 3. Alanine | |
| 4. DNA |
Activity 1.2 What makes it unique?
In two (2) sentences, describe the properties of the given biomolecule.
- Carbohydrates
- Lipids
- Nucleic Acids
- Proteins
Activity 1.3 Biomolecule represent!
Complete the table below.
| Sample | Type of Biomolecule | Function of the Sample |
|---|---|---|
| Hemoglobin | ||
| RNA | ||
| Plant fiber | ||
| Margarine |
What I Have Learned
Fill in the blanks.
- ____________________ are organic compounds that make up a living organism.
- Ratio of C:H:O of in a glucose is ____________________.
- Fat molecules are composed of glycerol and _________ _________.
- Amino acids are the building blocks of _________________.
- _________________________ _____________ is a type of nucleic acid that carries the genetic information of all living organisms.
What I Can Do
Now that you know the ideas and concepts of biomolecules. Give an example of products that you know for each biomolecule as per the indicated category.
| Biomolecule | Health Sciences | Industry |
|---|---|---|
| CARBOHYDRATE | ||
| LIPID | ||
| NUCLEIC ACID | ||
| PROTEINS |
Assessment
Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper.
- Which biomolecule has a biological function as a first-line source of energy’?
a. Carbohydrates
b. Lipids
c. Nucleic Acids
d. Proteins - Which represents a carbohydrate?
a. CnH2n+2
b. (CH2O)n
c. CnH2n
d. (C2HO)n - The following samples are simple carbohydrates except for _________
a. Cellulose
b. Fructose
c. Glucose
d. Sucrose - Which statement below best describes a lipid?
a. It is insoluble in water.
b. It is always in gaseous form.
c. Its general structure is only made up of carbon and hydrogen.
d. It can form ionic compounds due to its ability to become ionic. - Which structure below is rich in lipid as manifested by its function?
a. Human muscle fibers
b. Rigid cell wall of plant cells
c. Semi-permeable cell membrane
d. Enzymes catalyzing substances - Which one is NOT a lipid?
a. Cholesterol
b. Lactase
c. Triglyceride
d. Waxes - What is primarily the function of a nucleic acid?
a. As storage of energy of the body
b. As a source of energy of the body
c. As structural molecules of most living organisms
d. For storage and expression of genetic information - What does DNA mean?
a. Dinucleotide adenine
b. Dinucleic adenine
c. Deoxyribonucleic acid
d. Diribonucleic acid - Which of the molecules below IS NOT a part of a nucleic acid?
a. Amino acid
b. Nitrogenous base
c. Phosphate group
d. Sugar
For nos. 10-11, refer to the figure below:
[illustration: amino acid molecule diagram showing an amino group (N with H atoms) on the left, a central carbon with an H atom and a box labeled R, and a carboxyl group (C with O and H atoms, double-bonded O) on the right]
Figure 1 – Amino acid molecule (https://en.wikipedia.org/wiki/Amino_acid#/media/File:AminoAcidball.svg)
- What group is attached to the left side of the central Carbon?
a. Amino group
b. Hydrogen group
c. Acid group
d. Side Chains/Functional Groups - What makes an amino acid unique from each other?
a. The form of attachment
b. The different side chains
c. The manner of peptide bond
d. The presence of acids and bases - Which is rich in protein?
a. Plant leaves
b. Human hair
c. Vegetable oil
d. Table salt
For nos. 13-15, choices are:
a. Carbohydrate b. Lipid c. Nucleic Acid d. Protein
- Which constitutes a plant fiber?
- Which is a component of grease?
- Which has amino acids as its building blocks?
Additional Activities
Watch the video on https://www.youtube.com/watch?v=WtCCobhLqng entitled “Biological molecules – You are what you eat | Crash Course biology| Khan Academy”. Make a reflection of it using the four-square analysis.
[chart: four-square analysis graphic organizer; unnumbered, untitled]
- Top left: Technical terms you learned from the video
- Top right: Summary of the video in 10 sentences only
- Center: Title of the video
- Bottom left: Your insights about the topic being discussed on the video
- Bottom right: Questions you want to address
Answer Key
[transcriber’s note: this page is printed rotated 180 degrees; the answers below are read from the rotated text]
What I Know
- A
- B
- A
- A
- C
- B
- D
- C
- A
- A
- B
- B
- A
- B
- D
What I have learned
- BIOMOLECULES
- 1:2:1
- FATTY ACIDS
- AMINO ACID
- DEOXYRIBONUCLEI C ACID
[transcriber’s note: item 5 is split across two lines in the printed answer key]
Assessment
- A
- B
- A
- A
- C
- B
- D
- C
- A
- A
- B
- B
- A
- B
- D
References
- Bettelheim, F., Brown, W., Campbell, M., Farrell, S., and Torres, O. (2016). Introduction to General, Organic, and Biochemistry 11th ed., Cengage Learning, Boston, MA.
- Flowers, P., Theopold, K., Langley, R., Neth, E., and Robinson, W. (2019). Chemistry: Atoms First. Houston, Texas: Open Stax, . https://openstax.org/details/books/chemistry-atoms-first-2e.
- “Models of an Atom.” Siyavula Technology-Powered Learning. Accessed November 5, 2019. https://www.siyavula.com/read/science/grade-10/the-atom/04-the-atom-02.
- “Modern Atomic Theory: Models.” Atomic Structure, Periodicity, and Matter: Development of the Atomic Theory. Accessed November 5, 2019. http://www.abcte.org/files/previews/chemistry/s1_p6.html.
- https://www.youtube.com/watch?v=WtCCobhLqng
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