This document discusses biological molecules, including their classification, structure, and functions. It covers the main types of biological molecules: 1) Inorganic molecules like water, acids, bases, electrolytes, and carbon dioxide which are essential for life processes. Water acts as a solvent and is crucial for chemical reactions in the body. 2) Organic macromolecules including carbohydrates, lipids, proteins, and nucleic acids which are polymers formed from smaller organic subunits. Carbohydrates, proteins, and nucleic acids are synthesized through dehydration reactions between monomers. 3) The four main classes of biological macromolecules each have distinct monomeric subunits and play critical structural or functional

1. Biological Molecules
Prepared by:
MR. KEVIN FRANCIS E. MAGAOAY
Faculty, SHS Biology Department
C h a p t e r 8

2. Learning Objectives:
 Categorize the biological molecules according to
their structure and function
 Explain the role of each biological molecule in
specific metabolic processes

3. Overview:
 Definition of Biological Molecules
 Classification of Biological Molecules
 Structure and functions of Biological Molecules

4. Biological Molecules
 Biomolecules are essential
molecules for all living organisms
 Have unique characteristics and
properties that show how they
contribute to the structure and
function of the cells and how
essential they are in maintaining
life

5. Elements
The simplest form of a substance
found in the body such as C, H, O, N
Compounds
Made up of two or more elements that
are chemically joined together
Inorganic Compounds
Water, Acid, Bases, Salt, Carbon
Dioxide
Organic Compounds
Carbohydrates, Lipids, Proteins,
Nucleic Acids

6. Element
 Simplest form of a substance
 Cannot be broken down into more simpler form
 25 out of the natural elements are essential to
life
 98 – 99% of the body is composed of seven
major elements namely C, H, O, N, P, Ca, S

7. Symbol Name Functions
C Carbon
 Makes up 18% of the
mass of the human
body
 Main component of
organic compounds
H Hydrogen
 10% of human body
mass
 Essential in energy
production
O Oxygen
 61-65% of total
human body mass
 Used for cellular
respiration

8. Symbol Name Functions
N Nitrogen
 Makes up 3% of
human body mass
 Key element of protein
and nucleic acid
P Phosphorus
 1.2 – 1.5% of human
body mass
 Important for bone
structure
 Major component of
nucleic acid
S Sulfur
 0.20 – 0.25% of
human body mass
 Important components
of proteins

9. Symbol Name Functions
Ca Calcium
 1.5% of human body
mass
 Gives skeletal system
its rigidity and strength
 Found in bones and
teeth
 Important for muscle
functions
Si, Cl, Mg, Cu, Zn Minerals
 Other elements found
in the body in little
amounts
 Essential for growth
and maintenance of
the body

10. Symbol Name Functions
Fe & I Trace Elements
 Elements that are
indispensable to life
but is required in
minute amounts

11. Compounds
 A substance composed of two or more
elements that are chemically bonded together
 Can be classified into inorganic or organic
compounds
 Example: H2O, NaCl

12. Atomic Bonding
Atomic Bond Description
Covalent Bond
 Sharing of a pair of valence
electrons by two atoms
 Represents sharing of electron
 Done to satisfy the octet rule
Ionic Bond
 Attraction between oppositely
charged atoms (CATIONS,
ANIONS)
 Compounds formed from ionic
bonds are called ionic compounds
or salts

13. Atomic Bonding
Atomic Bond Description
Hydrogen Bonds
 Electronegativity
 The partial positive charge on
hydrogen atoms that is bonded in
an electronegative atom allows the
hydrogen to be attracted to different
electronegative atoms nearby
 Hydrogen bonds maybe
intramolecular or intermolecular

14. Atomic Bonding
Atomic Bond Description
Van der Waals Forces
 Weaker than hydrogen bonds
 Occur over a very short distance
 When many of these interactions
occur simultaneously, they can be
powerful

15. Inorganic Compounds
 Also known as Inorganic Biological Molecules
or Micromolecules
 These are compounds which are those without
carbon

16. Inorganic
Compounds
Water
Acids
BasesElectrolytes
Carbon
Dioxide

17. Water
 Versatile solvent
 Dissolves an enormous variety of solutes
necessary for living
 Results from the polarity of its molecules
 When water is in liquid form, its hydrogen
bonds are very weak. The hydrogen bonds
form, break and reform with great frequency

18. Characteristics and Functions of
Water
 Biological Solvent
Ability to dissolve many substances including
essential molecules in the body
 High Specific Heat
Large amount of heat is needed to increase its
temperature, thus it helps in maintaining the
constant body temperature

19. Characteristics and Functions of
Water
 High Heat of Vaporization
 Conversion of water from liquid to gaseous state which helps an
organism in preventing dehydration
 High Heat of Fusion
 Helps an organism to maintain constant body temperature at low
temperature
 Medium for Chemical and Physical Process
 Can serve as a place for gas and nutrient exchange and
elimination of wastes
 Means of transport

20. Acids
 A substance that increases the hydrogen ion
concentration of a solution
 When an acid dissolves in a solution, it donates
hydrogen ions

21. Weak vs Strong Acids

22. Base
 A substance that decreases the hydrogen ion
concentration of a solution
 When an acid dissolves in a solution, it accepts
hydrogen ions

23. pH Scale

24. Property Acid Base
pH
Less than 7 Greater than 7
Litmus paper
Blue to red Red to blue
Taste
Sour Bitter
Odor
Burning sensation Often no odor
Texture
Sticky Slippery
Reactivity
Reacts with metal to
produce hydrogen gas
Reacts with several fats
and oils

25. Electrolytes or Salts
 Produced when an acid is combined with a base
 Conducts electricity within the body
Na+OH- + H+Cl- Na+Cl- + H+OH-

26. Carbon Dioxide
 Essential for plants to perform photosynthesis
 Waste product from the breakdown of glucose

27. Organic Compounds
 Compounds containing carbon bonded to hydrogen
(hydrocarbon)
 Carbon atom is the backbone of all macromolecules

28. How to Illustrate Organic Compounds?
 Molecular Formula

29. How to Illustrate Organic Compounds?
 Structural Formula

30. Macromolecule
 Macromolecules are large molecules necessary for life
that are built from different combinations of smaller
organic molecules
 Polymers built from monomers such as:
 CHO
 CHON
 CHONP
 CHONPS

31. Macromolecule
Polymer
A long molecule consisting of many similar or
identical building blocks linked by covalent bonds.
Monomer
The repeating units that serves as a building
blocks of a polymer

32. Monomer
Monosaccharide - Monomer of Carbohydrates
Amino Acids - Monomer of Proteins
Nucleotides - Monomer of Nucleic Acids

33. Synthesis of Macromolecules
Dehydration Synthesis
Hydrolysis

34. Dehydration Synthesis
Monomers combine with each other using
covalent bond to form polymers

35. Hydrolysis
Polymers are broken down into monomers