SCI 402
Modern Biology
ENGR. GRACE R. DE CASTRO
INSTRUCTOR
Learning Objectives:
1. Identify and differentiate the different types,
classifications and give examples of microorganisms.
2. Understand the way our body defend itself against
diseases.
3. Differentiate between the different types of immunity.
4. Comprehend the concept of vaccination
Microbiology
Microbiology is the scientific
study of microorganisms,
which are living organisms
that are too small to be seen
with the naked eye.
Microorganisms
Microorganisms can be classified into several types based on
their characteristics and cell structure.
Here are some of the major types of microorganisms:
✓ bacteria
✓ viruses
✓ fungi
✓ protozoa
✓ algae
Some of the Major Types of Microorganisms:
They play crucial roles in
various aspects of life on
Earth.
Some microbes are
beneficial and essential for
human health, agriculture,
and the environment, while
others can cause diseases
in humans, animals, and
plants.
Bacteria
Bacteria are single-celled
organisms that lack a
nucleus and membrane-
bound organelles.
They are diverse and can
be found in various shapes,
such as rods, spheres, and
spirals.
Archaea
Archaea are another group of single-
celled organisms that are similar to
bacteria but have distinct genetic
and biochemical characteristics.
They are found in extreme
environments such as hot springs,
deep-sea hydrothermal vents, and
salt flats.
Examples of archaea include
Methanogens and Halophiles.
Fungi
Fungi are eukaryotic organisms,
meaning they have a nucleus and
membrane-bound organelles.
They can be single-celled (yeasts) or
multicellular (molds and mushrooms).
Examples of fungi include Candida
albicans (yeast), Aspergillus (mold),
and Agaricus bisporus (common
mushroom).
Protozoa
Protozoa are single-celled
eukaryotic organisms that are
typically motile and have complex
cellular structures.
They are found in various aquatic
and terrestrial habitats.
Examples of protozoa include
Amoeba, Paramecium, and
Plasmodium (causes malaria).
Algae
Algae are a diverse group of
photosynthetic organisms that can
be single-celled or multicellular.
They are found in aquatic
environments, including freshwater
and marine habitats.
Examples of algae include
Chlamydomonas (single-celled),
Spirogyra (filamentous), and Ulva
(multicellular seaweed).
Viruses
Viruses are unique infectious
agents that are smaller than cells
and can only reproduce inside
host cells.
They consist of genetic material
(DNA or RNA) enclosed in a
protein coat.
Examples of viruses include
Influenza virus, Human
Immunodeficiency Virus (HIV),
and Herpes simplex virus.
Prions
Prions are unconventional infectious
agents composed of misfolded
proteins.
They can cause diseases in humans
and animals, such as Creutzfeldt-
Jakob disease (CJD) and mad cow
disease (bovine spongiform
encephalopathy, or BSE).
Types of Pathogens
Some Branches of Microbiology:
1. Bacteriology
2. Virology
3. Mycology
4. Parasitology
Bacteriology
Bacteriology is the study of bacteria, which are single-celled
microorganisms.
Bacteria are found almost everywhere, including soil, water, and
the human body.
Some bacteria are beneficial and are used in food production,
biotechnology, and environmental cleanup.
Others can cause diseases such as tuberculosis, cholera, and
strep throat.
Acne Bacteria
Virology
Virology focuses on the study of
viruses, which are infectious
agents that can only replicate
inside living cells. Viruses are smaller
than bacteria and can cause a wide
range of diseases in humans, animals,
and plants.
Examples of viral diseases include
the common cold, influenza,
HIV/AIDS, and COVID-19.
Mycology
Mycology is the branch of microbiology
that deals with the study of fungi.
Fungi can be single-celled (yeasts) or
multicellular (molds and mushrooms).
They are essential decomposers in
nature, breaking down organic matter.
Some fungi have beneficial uses, such as
in the production of antibiotics, while
others can cause infections like athlete’s
foot and candidiasis.
Parasitology
Parasitology is the study of parasites,
which are organisms that live in or on
other organisms, called hosts, and obtain
nutrients from them.
Parasites include various protozoa (single-
celled organisms) and parasitic worms.
They can cause diseases such as malaria,
giardiasis, and schistosomiasis.
Microbiologists
Microbiologists employ various
techniques to study microorganisms,
including culturing and isolating them
in the laboratory, microscopic
examination, DNA sequencing, and
molecular techniques like polymerase
chain reaction (PCR) and gene
expression analysis.
Field of Microbiology
The field of microbiology is vital for
understanding infectious diseases,
developing vaccines and antibiotics,
maintaining food safety, studying the
ecology of microorganisms, and
advancing biotechnology and genetic
engineering.
It plays a significant role in medical
research, public health, agriculture,
and environmental science.
Understand the way our body defend itself against diseases.
Our body has a complex defense
system known as the immune system
that helps protect us against diseases.
Immune System
The immune system is composed of
various organs, cells, and molecules
that work together to recognize and
eliminate harmful pathogens, such as
bacteria, viruses, fungi, and parasites.
Here's a general overview of how the immune
system defends against diseases:
➢ Innate Immunity
➢ Adaptive Immunity
➢ Humoral Immunity
➢ Cellular Immunity
➢ Antigen Presentation
➢ Memory Cells
➢ Inflammatory Response
➢ Lymphatic System
Innate Immunity
The first line of defense is the
innate immune response, which is
present from birth and provides
immediate, nonspecific protection.
It includes physical barriers like the
skin and mucous membranes,
which prevent pathogens from
entering the body. If pathogens
manage to penetrate these
barriers, cells called phagocytes
engulf and destroy them.
Adaptive Immunity
The adaptive immune response is a more
specific defense mechanism that develops over
time. It involves two primary components:
a. Humoral Immunity: B cells, a type of white
blood cell, produce antibodies that bind to
specific antigens (foreign substances) present
on pathogens. These antibodies can neutralize
the pathogens directly or mark them for
destruction by other immune cells.
b. Cellular Immunity: T cells, another type of
white blood cell, recognize and eliminate
infected or abnormal cells directly. They can
also release chemical signals to coordinate
immune responses.
T cell and B Cell
Humoral Immunity Cellular Immunity
Antigen Presentation
Antigen-presenting cells (APCs)
play a crucial role in the immune
response.
They capture antigens from
pathogens and display them on
their cell surfaces, allowing other
immune cells to recognize and
respond to the specific pathogens.
Memory Cells
After an infection is cleared, some
immune cells, such as memory B
cells and memory T cells, persist in
the body.
They "remember" the specific
pathogens they encountered,
allowing for a faster and stronger
immune response upon re-
exposure to the same pathogen in
the future.
Plasma Cells vs. Memory B Cells
Both develop from activated B cells and both express
antibodies against a specific pathogen.
Inflammatory Response
Inflammation is a normal immune
response that helps contain and
eliminate pathogens.
When immune cells detect a threat,
they release chemicals that cause
blood vessels to dilate and become
more permeable.
This leads to increased blood flow
and the recruitment of immune
cells to the infected area, resulting
in redness, heat, swelling, and
pain.
Lymphatic System
The lymphatic system is a network of
vessels, lymph nodes, and organs that
helps circulate immune cells throughout
the body.
This system includes the bone marrow,
spleen, thymus, lymph nodes, and
lymphatic vessels (a network of thin
tubes that carry lymph and white blood
cells).
The tissues and organs that produce,
store, and carry white blood cells that
fight infections and other diseases.
It also plays a role in filtering and
trapping pathogens and foreign
substances.
Concept of Vaccination
Vaccination is a way to protect bodies from harmful diseases. It's like giving
the immune system a practice session, so it can learn how to fight off specific
germs.
Risk/Consequences of Vaccination:
1. Side Effects: Like any medical intervention, vaccines can have side effects. Most side effects
are mild, such as soreness at the injection site or low-grade fever, and they typically subside
within a few days. Note: Serious side effects are rare but can occur.
2. Allergic Reactions: In some rare cases, individuals may have allergic reactions to vaccine
ingredients. However, these reactions are extremely uncommon, and healthcare providers
are usually prepared to manage such situations.
3. Vaccine Misinformation: There is a lot of misinformation and myths surrounding vaccines,
leading to vaccine hesitancy or refusal. It's important to rely on credible sources and
scientific evidence when making decisions about vaccination.
4. Vaccine Availability: Vaccines may not be immediately accessible to everyone, especially in
low-income countries or during times of limited supply. This can create disparities in vaccine
distribution, impacting global efforts to control diseases.
Modern Biology
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Thank you!
