Biology and Chemistry: Understanding Life at the Molecular Level

BIOLOGY AND CHEMISTRY
PREPARED BY: MR. KENT E. GARCIA, LPT

OBJECTIVES
At the end of the lesson, the learners should be
able to:
• Discuss biology and chemistry;
• Explain the importance of studying biology and
chemistry;
• Name the early scientists and identify their
contributions to the development of biology as a
branch of science; and
• Identify the fields/branches of biology.

• Biology is the science that studies living organisms and
their interactions with one another and their
environments.
• Science attempts to describe and understand the nature
of the universe in whole or in part by rational means.
• Science has many fields; those fields related to the
physical world and its phenomena are considered
natural sciences.
• Science can be basic or applied.
Biology

• The main goal of basic science is to
expand knowledge without any
expectation of short-term practical
application of that knowledge.
• The primary goal of applied research,
however, is to solve practical
problems.
Biology

• The word biology is derived from Greek origin : bios
means life, and logos means science or study.
• Therefore, Biology is the science of living things that is
why biology is sometimes known as Life Science.
• The scope of the field is extensive and is divided into
several specialized disciplines, such as anatomy,
physiology, ethology, genetics, and many more.
Biology

• All living things share a few key traits: cellular organization, heritable genetic material
and the ability to adapt/evolve, metabolism to regulate energy needs, the ability to
interact with the environment, maintain homeostasis, reproduce, and the ability to grow
and change.
• All living organisms share several key properties such as order, sensitivity or response
to stimuli, reproduction, growth and development, regulation, homeostasis, and energy
processing.
• Living things are highly organized parts of a hierarchy that includes atoms, molecules,
organelles, cells, tissues, organs, and organ systems. Organisms, in turn, are grouped as
populations, communities, ecosystems, and the biosphere.
Biology

Biological Level of Organization

• The great diversity of life today
evolved from less-diverse
ancestral organisms over billions
of years.
• A diagram called a phylogenetic
tree can be used to show
evolutionary relationships among
organisms.
Biology

The Complexity of Life
• Despite its complexity, life is
organized and structured.
• The cell theory in biology states
that all living organisms are
composed of one or more cells.
• The cell is the basic unit of life,
and all cells arise from previously
existing cells.

• Even single-celled organisms (protists,
bacteria), such as bacteria, have structures
that allow them to carry out essential
functions, such as interacting with the
environment and carry out chemical
reactions that maintain life, or
metabolism.
• In multicellular organisms (plants,
animals, human), cells work together to
form tissues, organs, organ systems, and
finally, entire organisms. This hierarchical
organization can extend further into
populations, communities, ecosystems,
and the biosphere.

Example of Multicellular Organism

Genetics and Adaptation
• An organism’s genetic material, the biological
“blueprints” encoded in their DNA, is passed
down to their offspring.
• Over the course of several generations, the
genetic material is shaped by the biotic (living)
and abiotic (non-living) environment. This
process is called adaptation.
• Offspring of well-adapted parents have a high
likelihood to survive in conditions that are
similar to those that their parents lived in.

• The process in which inherited traits
increase survival and reproduction is called
natural selection.
• Natural selection is the central mechanism of
evolution.

Environmental Interactions
• Organisms must also be able to successfully
interact with their environment. This includes
being able to navigate the world around them in
search of resources or potential mates but also
includes regulating their internal environments.
• Homeostasis is the ability of an organism to keep
steady internal conditions. For example, humans
maintain constant body temperature. If they get
cold, they shiver; if they are too hot, they start to
sweat.
• Living things also maintain metabolism—the
chemical processes that regulate energy needs. For
instance, plants convert sunlight into sugar and
store chemical energy in adenosine triphosphate.

The basic principles of modern
biology
1. Cell theory is the principle that all
living things are made of
fundamental units called cells, and
all cells come from preexisting
cells.
2. Gene theory is the principle that all
living things have DNA, molecules
that code the structures and
functions of cells and get passed to
offspring.

The basic principles of modern biology
3. Homeostasis is the principle that all living things
maintain a state of balance that enables organisms to
survive in their environment.
4. Evolution is the principle that describes how all living
things can change to have traits that enable them to
survive better in their environments. These traits result
from random mutations in the organism's genes that are
"selected" via a process called natural selection. During
natural selection, organisms that have traits better-suited
for their environment have higher rates of survival, and
then pass those traits to their offspring.

Why we study biology?
• Through the study of biology, we are connected to the world around us
and how we interconnect with other life forms. With biology, we learn
how to conserve our nature which is vital to us and other living species.
• Biology is one of the fundamental sciences that medicine students and
other medical professionals need. It teaches different forms of organic
life and their interrelated relations with environment and other science.
• Genetics and physiology help us know how our body functions when
we breathe, eat or rest. This knowledge helps us to treat diseases,
consume proper nutrients and exercise our body.
• We human beings are biological organisms. We learn biology to know
how the human body is made, how it works, and what organs are in the
body. We must study biology because we must learn about life in our
environment.

Why we study biology?
• Some important reasons for studying biology have to do with
understanding how cells and organisms work. Biology involves the study
of life and how plants, humans and animals work. You will better know
how your body works. Biology touches your
life in many ways every day.
• Biology can tell us about the physical makeup of our bodies, which
enables us to produce cures and treatments for many diseases .The things
biology can also tell us about is plants of major importance and what plants
can help our body systems to be healthy. Biology also helps us know the
different body systems of different animals and also ourselves.
• Also biology can help us know more about the organisms in our
bodies. Biology can also tell us why animals act the way they do, also why
humans act the way we do.

Importance of studying Biology
• Humans beings are scientifically known as home
sapiens. They have similar characteristics with
apes but are more developed in terms of body
shape and erection, speech, and reasoning.
• And being considered as the highest form of
animals, humans have bodies that are complicated
to comprehend.
• But by studying biology, everyone will know the
reasons behind the sudden changes happening in
their respective bodies.
1. Explains the Changes of the Human Bodies

• Biology explains why such circumstances happen
and how the bodies produce the natural substances,
preventing anyone from thinking that there is
something wrong with their own bodies.
• Also, the importance of biology has produced the
scientific branch called Pathology, which studies
the different kinds of diseases and how they affect
the bodies of both humans and animals.
• It can also develop or discover new medications
that will alleviate some health conditions without
medicines yet.
1. Explains the Changes of the Human Bodies

2. Shapes Different Careers
• With this being said, it helps in
shaping the professional careers of
every person.
• Be it a doctor, chemist, engineer,
environmentalist, nurse, psychologist,
scientist, teacher, or other professions
that are not inclined to science,
studying the scientific concepts of life
and other living organisms is going to
be a useful tool in achieving success
in any chosen field of study.

3. Provides Answers to Large-scale Problems
• It will provide answers to large-scale concerns that may affect
anyone from different parts of the world. It can even offer
solutions to environmental issues without compromising or
sacrifice.
• For example, when a country is experiencing food shortages,
the biological ideologies can be utilized to develop efficient
and long-lasting methods for producing more food to sustain life.
• Another instance, which is currently one of the most evident
problems, is the existence of pollution. This branch of knowledge
can supply the solutions to eradicate such environmental
issue that has become much worse than before.

4. Teaches Concepts on Basic Living
• It teaches people how to plant for food consumption. Furthermore,
it tells what food is appropriate to consume and what is not.
• In some cases, biology has provided useful concepts and ideas
in building shelters effectively.
• It may seem an obvious factor, but it is only through
comprehending and interpreting the temperature of the human body
and how it mainly works that everyone can know what he or she
needs to eat and how to sleep comfortably.

5. Helps in Answering the Fundamental Questions About Life
The importance of biology can lead to the answers of life’s
fundamental questions such as;
• How and where did life begin?
• Where do humans come from?
• Was it God that made human beings?
• Or were they formed according to Charles Darwin’s
theory of evolution?

5. Helps in Answering the Fundamental Questions About Life
• Although there have been many instances when
science explained how life came to be, those
explanations have never been fully accepted due to
beliefs and principles related to religion.
• There is still a great portion that believes in what the
sacred scripture says. However, biology has been
consistent in explaining how life came to be despite
having no strong evidence of its claims. But its theories
remain to be important as of the present day.

6. Paves Way for Scientific Investigations
• Useful in discovering new things, through the
scientific method. Biologists do experiments to learn
significant and interesting facts about the world.
• They also do fieldwork, having expeditions and
explorations into unknown lands to gather more
information about life.
• It provides and is continuously providing everyone
with vital information about living organisms here on
Earth.
• It does not stop looking for solutions that can
completely eradicate the different environmental
issues still persisting today. Instead, it pursues in
getting strong evidence on how life came to be.

Chemistry
• Chemistry is the study of matter and its interactions with other
matter and energy.
• Often known as the central science, it is a creative discipline
chiefly concerned with atomic and molecular structure and its
change, for instance through chemical reactions.
• Chemistry, the science that deals with the properties, composition,
and structure of substances (defined as elements and compounds),
the transformations they undergo, and the energy that is released or
absorbed during these processes. Every substance, whether
naturally occurring or artificially produced, consists of one or more
of the hundred-odd species of atoms that have been identified as
elements.

Chemistry :
The Central Science

Qualitative and Quantitative
Chemistry
Qualitative analysis in chemistry gives the
presence or absence of
different chemical components in a sample.
Quantitative analysis in chemistry gives the
amount of different chemical components
present in a given sample.

Chemistry
It’s Everywhere
Chemicals are everywhere and are everything. Anything you
can touch or smell or see contains one or more chemicals.
Many occur naturally but some are man made.
It’s Discovery
Chemists discover naturally occurring chemicals and also
make new ones never seen before. Chemists study the
properties of the natural and man made chemicals. This
information is used to understand how some chemicals may
be modified to make them more useful and they develop the
methods to make the modifications.

Chemistry
It’s in Everything
Chemists seek to study the natural world but also seek to
improve it by modification on a molecular level. Because
everything is a chemical, chemistry is one of the foundations
of modern industrial economies.
It Improves our World
Advancements in the field of chemistry have brought about
major improvements in our world. Improvements range from
new medicines that cure disease, to new materials that make
us safer and stronger, to new sources of energy that enable
new activities.

Importance of studying Chemistry
• Cooking: Chemistry explains how food changes as you cook it, how it
rots, how to preserve food, how your body uses the food you eat, and
how ingredients interact to make food.
• Cleaning: Part of the importance of chemistry is it explains how
cleaning works. You use chemistry to help decide what cleaner is best
for dishes, laundry, yourself, and your home. You use chemistry when
you use bleaches and disinfectants, even ordinary soap and water. How
do they work? That's chemistry.
• Medicine: You need to understand basic chemistry so you can
understand how vitamins, supplements, and drugs can help or harm
you. Part of the importance of chemistry lies in developing and testing
new medical treatments and medicines.

• Environmental Issues: Chemistry is at the heart of environmental
issues. What makes one chemical a nutrient and another chemical a
pollutant? How can you clean up the environment? What processes can
produce the things you need without harming the environment?
• We humans are all chemists. We use chemicals every day and perform
chemical reactions without thinking much about them. Chemistry is
important because everything you do is chemistry! Even your body is
made of chemicals.
• Chemical reactions occur when you breathe, eat, or just sit there
reading. All matter is made of chemicals, so the importance of
chemistry is that it's the study of everything.

• Chemistry is essential for meeting our basic needs of food, clothing,
shelter, health, energy, and clean air, water, and soil.
• Chemical technologies enrich our quality of life in numerous ways by
providing new solutions to problems in health, materials, and energy
usage. Thus, studying chemistry is useful in preparing us for the real
world.
• Chemistry is often referred to as the central science because it joins
together physics and mathematics, biology and medicine, and the earth
and environmental sciences.
• Knowledge of the nature of chemicals and chemical processes
therefore provides insights into a variety of physical and biological
phenomena.

• Knowing something about chemistry is worthwhile because it provides
an excellent basis for understanding the physical universe we live in.
For better or for worse, everything is chemical!

Famous Biologists
and their
Contributions to the
Development of
Biology

Hippocrates (c.460 BC-c.370 BC)
➢ Nationality: Greek
➢ Known for: The Father of Western Medicine
➢ Wrote On the Physician, a guide outlining
how a physician should treat their patients.
Also authored the Hippocratic Oath, which
doctors still use today as part of their practice.
Biologists of Antiquity

Written in antiquity, its principles
are held sacred by doctors to this
day: treat the sick to the best of
one's ability, preserve patient
privacy, teach the secrets of
medicine to the next generation,
and so on.

Aristotle (384 BC-322 BC)
➢ Known for: Classified organisms into a “Ladder of
Life”
➢ Aristotle was the first to categorize animal life based
on their characteristics. He separated them into two
categories: “animals with blood” and “animals without
blood.” Many of his theories lasted all the way until the
19th century.

Galen (c.129-c.200-216)
➢ Known for: First to introduce medicinal experimentation
➢ Galen performed dissections on animals in hopes of
learning more about the human anatomy. He was the
first to discover that the voice comes from the larynx.
He also studied the circulatory system and discovered
the difference between arterial and venous blood.

Andreas Vesalius (1514-1564)
• Nationality: Brabantian
• Known for: Published On the Fabric of the Human
Body
• Often referred to as the “founder of modern human
anatomy,” Vesalius disproved theories that were several
centuries old about the human body. His study of the
human skull helped create the field of biological
anthropology, which studies how the human species has
developed over time.
Biologists of the Middle Ages (1500-1700)

Anton van Leeuwenhoek (1632-1723)
• Nationality: Dutch
• Known for: The Father of Microbiology
• As the first person recorded to describe single-cell
organisms, Leeuwenhoek is often referred to as the
world’s first microbiologist. Some of the single-cell
organisms he observed include blood cells, sperm cells,
and others. He handcrafted his own microscopes for
doing his research.

Robert Hooke (1635-1703)
• Nationality: English
• Known for: Coined the term “cell”
• Hooke studied microscopic fossils and as a result of his
finding, he was an early supporter in the theory of
biological evolution. He also published Micrographia in
1665, one of the best-selling science books of his day. It
included illustrations of his microscopic images,
including a fly’s eye.

Joseph Priestley (1733-1804)
• Known for: Believed to have discovered oxygen
• Priestley is one of the men believed to have discovered
oxygen. He also invented soda water by dissolving
heavy gas in water. He won a medal in 1773 from the
Royal Society for this discovery. He was also the first to
observe photosynthesis.
Biologists of the 1700s

Antoine Lavoisier (1743-1794)
• Nationality: French
• Known for: Observing metabolism
• Lavoisier is best known in the field of biology for his
work concerning metabolism. He hooked up a
calorimeter to a guinea pig in order to measure the heat
produced. He also conducted several experiments
involving combustion.

Edward Jenner (1749-1823)
• Known for: Created the first effective vaccine for
smallpox
•
Developed the first experimental vaccine which was
used to treat smallpox. He also coined the term
“vaccination” and is often referred to as the “father of
immunology.” Jenner also helped establish what is now
the Royal Society of Medicine.

Alexander Von Humboldt
(1769-1859)
• Nationality: Prussian
• Known for: Humboldtian science
• Helped establish the field of biogeography, which is the
study of ecosystems and species throughout geological
time and space. Humboldtian science is also named for
him, which is the belief that the most modern and
accurate resources should be used for collecting data.

Charles Darwin (1809-1882)
• Known for: Theory of Evolution
• Darwin theorized that all species of life came from
common ancestors that evolved over millions of years.
He called this process “natural selection.” He published
his ideas in a work entitled On the Origin of Species.

Claude Bernard (1813-1878)
• Known for: Blind experimental method for objective
results
• By suggesting using blind experiments to conduct
studies, Bernard helped researchers get more objective
results to their experiments. He also did studies on the
pancreas gland, the liver, and parts of the body’s
nervous system.

Gregor Mendel (1822-1884)
• Nationality: German
• Known for: Plant hybridizations and genetics
• Mendel worked with plants, peas, and honeybees to test
his theories regarding genetics. He is credited with
being the founder of the science of genetics and
discovering a set of laws about genetic patterns, now
called the Mendelian inheritance.

Louis Pasteur (1822-1895)
• Known for: Created the process of pasteurization for
treating milk and wine
• Performed experiments that supported the germ theory
of disease, which stated that diseases are caused by
microorganisms. He also co-founded the field of
microbiology and created vaccines for anthrax and
rabies.

Joseph Lister (1827-1912)
• Nationality: British
• Known for: Using antiseptics for cleaning and sterilizing
wounds
• As a professor of surgery. Lister introduced the idea of
sterilizing surgical instruments with carbolic acid to help
prevent infection. He came to be known as the “father of
antisepsis” due to his work. He also developed better
methods for mastectomies and repairing kneecaps.

Ernst Mayr (1904-2005)
• Nationality: German
• Known for: The Darwin of the 20th Century
• In an attempt to solve the “species problem” of
Darwin’s work, Mayr published Systematics and the
Origin of Species to explain his ideas regarding
evolutionary biology. His work and findings influenced
future theories, such as the theory of punctuated
equilibrium.

Erwin Chargaff (1905-2002)
• Nationality: Austrian
• Known for: Chargaff’s rules regarding DNA structure
• Chargaff is known mainly for discovering two rules
related to the DNA structure and its double helix
formation. He found that certain substances within the
DNA structure are equal to other substances. He also
found that the DNA composition varies from one
species to another.

Rachel Carson (1907-1964)
• Nationality: American
• Known for: Warning the public about the dangers of
pesticides
• Marine biologist whose work helped lead to the creation
of the Environmental Protection Agency. Carson
published several books about sea life in her early
career, but later helped change governmental policies
regarding the use of certain pesticides.

Biology and Chemistry: Understanding Life at the Molecular Level

Biology and Chemistry: Understanding Life at the Molecular Level

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