Biomolecules: Proteins The bond formed is called a peptide bond, and the

Proteins are made up of the elements carbon, hydrogen, product is a dipeptide because it is made up of two
oxygen, nitrogen and sulfur. They are the most versatile amino acid units. Longer chains are called polypeptides
macromolecules in living systems and serve crucial functions and chains of 50 or more amino acids are called
in essentially all biological processes. They act as catalysts, proteins.
they transport and store other molecules such as oxygen, Your body does not store amino acids, so it needs a regular
they provide mechanical support and immune protection, daily supply of these essential building blocks. Nonessential is
they generate movement, they transmit nerve impulses, and a slightly misleading label because these amino acids fill
they control growth and differentiation. (Freeman and essential roles, but since they’re synthesized by your body,
Company, 2002) they’re not an essential part of your diet. Of the 11
Proteins of “prime importance” comprise 10-30 percent of nonessential amino acids, eight are called conditional amino
cell mass and have many physiological functions. All enzymes, acids. The list of conditional amino acids includes arginine,
blood proteins, hemoglobin, and antibodies are functional glutamine, tyrosine, cysteine, glycine, proline, serine, and
proteins. All proteins contain C, O, H, and N and may have ornithine. The remaining three - alanine, asparagine, and
other elements as well. (Barbara Liang, 2020) aspartate - are nonessential.
Proteins are built from 20 common building blocks called Generalization
amino acids. Differences in the R-group identifies the various The types of amino acids are arginine, glutamine, tyrosine,
amino acids. The primary structure cysteine, glycine, proline, serine, and ornithine. The
Of a protein molecule is determined by the sequence of remaining three - alanine, asparagine, and aspartate - are
amino acids connected by peptide bonds forming a nonessential. Nonessential is a slightly misleading label
polypeptide chain. Depending upon the protein, the molecule because these amino acids actually fill essential roles, but
could have less than 100 amino acids or as many as several since they’re synthesized by your body, they’re not an
thousand in its chain. essential part of your diet.
Types of protein Protein Structure
Protein is found in many foods, some of the most common The picture below represents a protein and its structure.
are meat, fish, eggs, nuts, seeds, legumes, tofu and
vegetables.

Another type of protein is the enzymes. It is known as

biological catalysts. You have learned the amazing action of
catalysts particularly during digestion process. The role of an
enzyme can be compared to a lock and a key. The lock will
not open unless you use the right key. In the same manner an
enzyme works for a specific substrate like the enzyme lactase.
The food we eat is classified into complete protein and Its role is to breakdown the sugar lactose into glucose and
incomplete protein. galactose.
Complete protein are foods that contain all the essential Figure 2 below is the mechanism of peptide bond formation is
amino acids our bodies need. Meat, fish, seafood, eggs and a dehydration synthesis process. During the formation of a
soy contain complete protein. peptide bond, the carboxyl group of one amino acid moves
Incomplete protein is found in nuts, grains, fruits and towards the amino group of another amino acid.
vegetables and do not contain all the essential amino acids. Subsequently, one hydrogen and one oxygen atoms are lost
We need to eat a variety of these to get what we need. from the carboxyl group (COOH) of the first amino acid. In
(Primary Leap, 2020). contrast, one hydrogen is lost from the amino group (NH2) of
Generalization the other amino acid. This results in the release of a water
Proteins are polymers of amino acids. Proteins are made up molecule (H2O) along with the formation of an amide bond
of the elements carbon, hydrogen, oxygen, nitrogen and (C-N) between the two amino acids. Because this reaction
sulfur. They are found as structural materials in hair, nails and involves the removal of a water molecule, it is called a
connective tissues. Enzymes are proteins that act as biological dehydration synthesis reaction.
catalysts.
Proteins: Amino acids
Amino acids are the building blocks of proteins. Of the 20
amino acids found in human protein, only 11 can be
synthesized by the body and 9 have to be supplied by the
foods we eat. These 9 amino acids are also called essential
amino acids. Adults only need to obtain eight of them: valine,
isoleucine, leucine, lysine, methionine, phenylalanine,
threonine and tryptophan. The ninth amino acid - histidine - is
only essential for infants. Proteins are characterized by their primary, secondary,
Let us talk about more about the amino acids found in tertiary and quaternary structures.
protein. When two The kind of amino acids, which make up the chain, the
amino acids react with each other in an acid-base reaction, a sequence in which the amino acids are arranged and the
peptide is formed. The basic amino group of one amino acid length of the chain distinguishes the primary structure of
reacts with the acidic carboxylic group of another amino acid, proteins. Primary structure differentiates normal protein from
forming the peptide, and a molecule of water is lost. This abnormal one. Normal adult hemoglobin (HbA) is made up of
reaction mentioned above is classified as a condensation 2 α-chains and 2 β-chains. Each α-chain has 141 amino acids
reaction because the two amino acid molecules join together and each β-chain has 146 amino acids arranged in a specific
and water is formed. sequence. A person whose body makes only sickle cell
hemoglobin will suffer symptoms of sickle cell anemia.
These occur because the glutamic acid-to-valine amino acid
change makes the hemoglobin molecules assemble into long
fibers. 8. Proteins are also considered as _____.
The secondary structures of proteins refer to the coiling of A. Macromolecules B. Micro molecules
the protein chain into a α–helix structure, formation of b C. Molecules D. Moles
sheets, or twisting into random structures. 9. The production of proteins helps our body _____.
These structures are the results of interactions between R A. Grow B. Function C. Move D. Replicate
groups, H-bonding or formation of –S-S- bonds between 10. Proteins are known to be a prime important because it
chains. Protein molecules are so long that they automatically consists _____percent of cell mass.
coil, fold or twist. The resulting shape is unique for each A. 30 B. 40 C. 50 D. 60
polypeptide in a particular medium, at a particular pH. Assessment:
The tertiary structure describes the shape of the coiled chain Write TRUE if the statement is correct about amino acid and
when it is folded or hydrated in its natural state. Finally, FALSE if it is wrong. Write your answer on a separate sheet of
there’s one special type of covalent bond that can contribute paper.
to tertiary structure: the disulfide bond. Disulfide bonds, ___________1. Amino acid is the building block of proteins.
covalent linkages between the sulfur-containing side chains of ___________2. There are 20 amino acids found in human
cysteine’s, are much stronger than the other types of bonds protein, only 11 can be Synthesized by the body.
that contribute to tertiary structure. They act like molecular ___________3. Nine of these amino acids have to be supplied
"safety pins," keeping parts of the polypeptide firmly by the foods We eat.
attached to one another. ___________4. Our body doesn’t store amino acids, so it
The quaternary protein structure involves the clustering of needs a regular daily Supply of these essential building blocks.
several individual peptides into a final specific shape. A ___________5. Shorter chains of amino acids are called
variety of bonding interactions including hydrogen bonding, polypeptide.
salt bridges and disulfide bonds hold the various chains into a Post-assessment
particular geometry. In general, the same types of Multiple Choice: Select the correct from the given choices.
interactions that contribute to tertiary structure (mostly weak Write your answer on a separate sheet of paper.
interactions, such as hydrogen bonding and London 1. All amino acids that are found in proteins, EXCEPT for
dispersion forces) also hold the subunits together to give proline, contain a(n):
quaternary structure. A. Amino group B. Carbonyl group C. Carboxyl group D. Ester
Lack of protein in the body causes malnutrition also known as group
Kwashiorkor, which affects children in underdeveloped 2. Amino acids are _____molecules since they contain carbon
countries. Protein malnutrition usually goes hand in hand on it.
with calorie malnutrition and referred to as Protein Energy A. Compound B. Inorganic C. Organic D. Substance
Malnutrition (PEM). 3. The chirality of an amino acid results from the fact that it’s
Generalization a carbon is______
Protein structure of amino acids, which make up the A. Symmetric.
chain, the sequence in which the amino acids are B. Carboxylic acid
arranged and the length of the chain distinguishes the C. Bonded to four different chemical groups.
primary structure of proteins. The secondary structures D. In absolute configuration in a naturally occurring protein.
of proteins refer to the coiling of the protein chain into a 4. The only amino acid that is essential to the for infants
α–helix structure, formation of b sheets, or twisting into needed for their growth and
random structures. The tertiary structure describes the Development.
shape of the coiled chain when it is folded or hydrated in A. Histidine B. Isoleucine C. Lysine D. Threonine
its natural state. The quaternary protein structure 5. It is known as the building block of protein.
involves the clustering of several individual peptides into A. Amino acid B. Amino group C. Essential D. Nonessential
a final specific shape. Protein malnutrition usually goes Assessment:
hand in hand with calorie malnutrition and referred to as Choose your answer from the words inside the parenthesis.
Protein Energy Malnutrition (PEM). Write your answer on a separate sheet of paper.
Activity on Protein: Post-assessment Proteins are characterized by their _____ 1. (primary,
Multiple Choice. Read each question carefully, then choose utmost), secondary, tertiary and quaternary structures. The
the letter of the correct answer. Write the letter of your kind of ______ 2. (amino acids, protein), which make up the
answer on a separate sheet of paper. chain, the sequence in which the amino acids are arranged
1. What does protein do for you? and the length of the chain distinguishes the _____ 3.
A. It helps you grow . (primary, secondary) structure of proteins. The _____4.
B. It helps you get free candy. (primary, secondary) structures of proteins refer to the coiling
C. It helps you change hair color . of the protein chain into a α–helix structure, formation of b
D. It helps you get popular in school. sheets, or twisting into _____ 5. (arrange, random)
2. What happens if you intake too much protein? structures. These structures are the results of interactions
A. Nothing B. Weight gain C. You die D. You explode between_____ 6. (R groups, S groups), H-bonding or
3. What types of food do vegetarians rely on to get protein? formation of –S-S- bonds between chains. _____ 7. (Amino
A. Candy B. Chicken C. Meat D. Plants acid, Protein), the molecules are so long that they
4. Protein can be found in. automatically _____ 8. (coil, stretch) fold or twist. The
A. Bananas B. Meat C. Potatoes D. Tomatoes resulting shape is _____ 9. (simple, unique) for each
5. What are some signs that you are not getting enough polypeptide in a particular medium, at a particular pH. The
protein? _____10. (secondary, tertiary) structure describes the shape
A. Your nails fall off B. Your hair falls out of the coiled chain when it is folded or hydrated in its natural
C. You shrink in height D. You fall asleep in random places state.
6. Which of the following foods are good sources of protein?
A. Bread B. Meat, Fish, Egg C. Packets of Sweets D. Rice
7. What percentage of the human body is made up of
proteins?
A. 7% B. 20% C. 50% D. 87%
Biomolecules: Nucleic Acids Concept Development:
Overview
Ribonucleic acid, or RNA, is also present in the nuclei of living
Nucleic Acids are molecules that code for hereditary traits by
things, although there are certain types of RNA viruses that
controlling the production of protein. Like proteins, nucleic
only contain RNA, and not DNA. There are now several known
acids are long chain of polymers consisting of simpler units or
classes of RNA, but three major types are transfer RNA,
monomers. There are two kinds of nucleic acids: DNA, or
messenger RNA, and ribosomal RNA-are mostly responsible
deoxyribonucleic acid; and RNA, or ribonucleic acid. DNA
for all of the action in the nucleus that pertains to the genetic
found mainly in the cell nuclei contains the genetic
information. RNA carries the information along, is responsible
information that codes for the sequences of amino acids in
for the growth of new proteins, and creating peptide bonds.
proteins. RNA is found in many places in the cell and carries
DNA and RNA are made up of three parts: a five carbon sugar
out the synthesis of proteins.
(pentose), a phosphate group, and a ringshaped base
Nucleic acids are the fourth class of biological molecule.
containing nitrogen.
Nucleic acids are responsible for the transmission of inherent
Figure 1, below show a model of a nucleotide, the sphere
characters from parent to the offspring.
represents a phosphate group, the pentagon represents a
They are responsible for the synthesis of protein in our body.
five–carbon sugar (pentose) and the rectangle represents a
DNA fingerprinting is a method used by forensic experts to
nitrogen-containing base.
determine paternity. A nucleic acid is a nitrogen containing
biological polymer that is involved in storage and
transmission of genetic information.
Concept Development:
Nucleic acids are the fourth class of biological molecule.
Nucleic acids are responsible for the transmission of inherent
characters from parent to the offspring.
They are responsible for the synthesis of protein in our body.
Figure 1. Show a model of nucleotide
DNA fingerprinting is a method used by forensic experts to
There are two kinds of nucleic acids: DNA, or
determine paternity. A nucleic acid is a nitrogen containing
deoxyribonucleic acid; and RNA, or ribonucleic acid. DNA are
biological polymer that is involved in storage and
found mainly in the cell nuclei contains the genetic
transmission of genetic information.
information that codes for the sequences of amino acids in
Nucleic acids are the main information-carrying molecules of
proteins while RNA are found in many places in the cell. RNA
the cell and play a central role in determining the inherited
carries out the synthesis of proteins. The monomers of
characteristics of every living thing. Nucleic acids have a far
nucleic acids are nucleotides.
more important-sounding name: the building blocks of life.
These components are found in DNA and RNA of every living Table 1 below discusses the differences between RNA
thing on the planet. They're located in the nucleus of all living and DNA, its’ structure and function.
cells, and have a variety of jobs, including the construction of DNA RNA
proteins, the replication of the cells for longevity and growth,
the containment of genetic material that is passed to Description It contains the It is responsible for
offspring, and more. genetic the template in the
There are five chief types of components in nucleic acids: instruction synthesis of proteins
cytosine, guanine, thymine, uracil, and adenine. Whether the used in which in turn control
acid contains uracil or thymine determines whether it is DNA the the
(thymine) or RNA (uracil). development operation & function
and of the cell
Each nucleotide has three parts namely: inorganic phosphate
functioning of
group, five-carbon monosaccharide sugar, and a nitrogen
all living
base. organisms.
In a nucleic acid, the sugar of one bonds to the phosphate of
another. This makes them string together in a chain. Each Function Long-term Transfer the genetic
sugar is also bonded to a nitrogen base. Examples of nucleic storage and information for the
acids: DNA (Deoxyribonucleic Acid), RNA (Ribonucleic Acid), transmission creation of proteins
Artificial Nucleic Acids, and Mutations (Regina Bailey, 2020) of genetic from the nucleus to
The Functions of Nucleic Acids information the ribosomes`
Nucleic acids are responsible for the transmission of inherent
characters from parent to offspring. They are responsible for Sugar and Deoxyribose Ribose sugar
the synthesis of protein in our body. DNA fingerprinting is a Bases sugar Phosphate backbone;
method used by forensic experts to determine paternity. It is Phosphate Four Bases: adenine,
also used for the identification of criminals. It has also played backbone; guanine, cytosine,
a major role in studies regarding biological evolution and Four Bases: and
genetics. adenine, uracil
Generalization guanine,
Nucleic Acids are molecules that code for hereditary traits by cytosine, and
controlling the production of protein. Nucleic acids are thymine
responsible for the transmission of inherent characters from
parent to offspring. They are responsible for the synthesis of Pairing of A-T (Adenine- A-U (Adenine-Uracil)
protein in our body. DNA fingerprinting is a method used by Bases Thymine) G-C (Guanine-
forensic experts to determine paternity. G-C Cytosine)
(Guanine-
Nucleic Acid: DNA & RNA
Cytosine)
Nucleic acids are involved in the preservation, replication, and
The figure below is about DNA that is typically double
expression of hereditary information. Two major types of
stranded, whereas RNA is typically single stranded. Although
nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic
it is single stranded, RNA can fold upon itself, with the folds
acid (RNA).
stabilized by short areas of complementary base pairing
within the molecule, forming a three-dimensional structure.
Generalization
DNA that is typically double stranded, whereas RNA is
typically single stranded. DNA are found mainly in the cell
nuclei contains the genetic information that codes for the
sequences of amino acids in proteins while RNA are found in
many places in the cell. RNA carries out the synthesis of
proteins.
Nucleic Acid Process
The process of DNA duplication is called DNA replication.
Replication follows several steps that involve multiple
proteins called replication enzymes and RNA. In eukaryotic
cells, such as animal cells and plant cells, DNA replication
occurs in the S phase of interphase during the cell cycle.
The protein synthesis, mRNA carries genetic codes from the
DNA in the nucleus to ribosomes, the sites of protein
translation in the cytoplasm.
The process of DNA duplication is called DNA replication.
Replication follows several steps that involve multiple
proteins called replication enzymes and RNA. In eukaryotic
cells, such as animal cells and plant cells, DNA replication
occurs in the S phase of interphase during the cell cycle.
RNA, the three most well-known and most commonly studied
are messenger RNA (mRNA), transfer RNA (tRNA), and
ribosomal RNA (rRNA), which are present in all organisms.
These and other types of RNAs primarily carry out
biochemical reactions, similar to enzymes. Some, however,
also have complex regulatory functions in cells. Owing to their
involvement in many regulatory processes, to their
abundance, and to their diverse functions.
RNAs play important roles in both normal cellular processes
and diseases.
In protein synthesis, mRNA carries genetic codes from the
DNA in the nucleus to ribosomes, the sites of protein
translation in the cytoplasm.
Ribosomes are composed of rRNA and protein. The ribosome
protein subunits are encoded by rRNA and are synthesized in
the nucleolus. Once fully assembled, they move to the
cytoplasm, where, as key regulators of translation, they
“read” the code carried by mRNA.
A sequence of three nitrogenous bases in mRNA specifies
incorporation of a specific amino acid in the sequence that
makes up the protein. Molecules of tRNA (sometimes also
called soluble, or activator, RNA), which contain fewer than
100 nucleotides, bring the specified amino acids to the
ribosomes, where they are linked to form proteins.
Generalization
The process of DNA duplication is called DNA
replication. RNA, the three most well-known are
messenger RNA (mRNA), transfer RNA (tRNA), and
ribosomal RNA (rRNA), which are present in all
organisms. RNAs play important roles in both normal
cellular processes and diseases.