Basic Biology-1
Dr. Badria Almurshidi
Assistant Professor (Molecular Medicine & Toxicology)
Department of Biology, College of Science
UAE University, Al Ain
Basic Biology 1
Assessment:
Proposed grading of the course is as follows:
1.
2.
3.
4.
Homework/Assignments/Presentation: 10%
Quizzes:
40%
Midterm exam:
20% .
Final exam:
30%
100%
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Biology is the study of life
Absolutely!
Investigation of living organisms leads to
unforeseen discoveries that no one
would imagine!
Pacific yew tree
and cancer
treatment
Crystal Jelly
fish and GFP
discovery
Arrowhead Viper
and inhibitors of
high blood pressure
Streptomyces
griseus soil bacteria
and streptomycin
White willow tree and
aspirin
Characteristics of Life
1.
2.
3.
4.
5.
6.
7.
Cells and organization
Energy use and metabolism
Response to environmental changes
Regulation and homeostasis
Growth and development
Reproduction
Evolution
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Cells and organization: All living things can be called
organisms. The simplest unit of an organism is the cell. The
cell theory states that all organism are made of cells. In plants
and animals, each cell has internal order and the cells within
the body have specific arrangements and functions.
Energy use and Metabolism: Living things cannot maintain
their organization (internal order) or carry on life’s activities
without an outside source of materials and energy.
Energy is the capacity to do work. Cells use energy by
catalyzing a variety of chemical reactions leading to the
breakdown of nutrients (provided by the food) and the synthesis
of the components that make up cells and organisms.
Metabolism encompasses all the chemical reactions that
occur in a cell. The sun is the ultimate source of energy for
nearly all life on the planet. Plant and certain other organisms
are able to capture solar energy and carry on Photosynthesis
to produce their own nutrients. Photosynthesis is the process
that transform solar energy into chemical energy in the bonds
of organic nutrient molecules.
Response to environmental changes: Living organisms
respond to environmental changes to promote their survival.
The responses to environmental changes are examples of
adaptations. Adaptation is any modification that makes an
organism suited to its way of life.
Regulation and homeostasis: is the property of a living
organism, to regulates its internal environment so as to maintain
a stable, constant condition. Multiple dynamic equilibrium adjustments and regulation mechanisms make
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homeostasis possible. The term was from the Greek homoios (same,) and stasis (to stand).
Growth and development: Living organisms grow and
develop. Growth produces more or larger cells while
Development a series of changes in the state of a cell,
tissue , organ or organism. Development produces
organisms with a defined set of characteristics.
Reproduction: Every type of living thing can reproduce,or
make another organism like itself. In most
multicellular organisms, reproduction begins with
the union of two gametes from different individuals.
Organizational instructions encoded in genes. Genes are
composed of DNA
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Levels of Organization
1. Atoms
2. Molecules and macromolecules
3. Cells
4. Tissues
5. Organs
6. Organism
7. Population
8. Community
9. Ecosystem
10. Biosphere
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Levels of Organization
1. Atoms are the smallest unit of matter.
2. Molecules are a group of atoms bonded with each other. Macromolecules are formed when
many molecules bond together to form a polymer (carbohydrates, DNA, RNA etc.).
3. The cell is the smallest unit of biological organization that biologists consider alive. Molecules
and macromolecules associate with each other to form larger structures such as membranes.
Cells are surrounded by a plasma membrane, carry out complex chemical reactions, and are at
least potentially capable of self reproduction.
Cells come in a wide variety of shapes and sizes.
Not all cells have a nucleus, but again all true cells have genetic material in the form of DNA.
4. Tissue is a group of similar cells that associate with each other to carry out a specific set of
functions. For example:
. Muscle tissue is for contraction.
. Connective tissue is tissue consisting of cells surrounded by a large amount of non living
material.
. Nerve tissue is for the conduction of nerve impulses and secretion of specialized chemicals
called neurotransmitters.
5. Organs are groups of two or more types of tissues organized together to carry out a
particular set of functions. Organs typically have several kinds of tissue. The heart is composed
of several type of tissues, including muscle, nervous and connective tissue.
Levels of Organization
6. The organism or individual is that level of biological organization that has its own distinct
existence as a complex, self reproducing unit. All living things can be called organisms.
We are multicellular organisms in that we are made of many highly specialized cells which cannot
exist independently of other cells in the organism. Many organisms are unicellular, that is consist
of a single independent cell.
Organisms are classifies as belonging to a particular species, which is a related group of organims.
The members of the same species are closely related genetically.
7. Population is group of freely interacting and breeding individuals of the same species that
occupies the same environment.
8. Community is all the populations of different species living and interacting together in a distinct
area. (e.g: all the species in a prairie). The type of species that are found in a community are
determined by the environment and by the interactions of species with each other.
9. Ecosystem is formed by interactions of a community of organisms with their physical (non living)
environment.
10. Biosphere is the region on (land), below (water), and above (air) the Earth's surface where life
exists. Living things can be found well into the atmosphere, the deepest parts of the ocean, and at
least in some areas, microbes live in rock several kilometers below the surface of the earth.
The levels of Biological Organization
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Classification of Living Organisms
Taxonomy is the grouping of species based on common ancestry.
All forms of life can be placed into three large categories or DOMAINS:
. Bacteria- unicellular prokaryote
. Archaea- unicellular prokaryote (bacteria-like
organisms that live in extreme aquatic
environments.
. Eucarya- unicellular to multicellular eukaryotes
Organisms in domain eucarya are subdivided into 4
KINGDOMS:
. Protista
. Fungi
. Plantae
. Animalia
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Classification of Living Organisms
Living organism
Prokaryotic cell
Bacteria
Archaea
Protists
Eukaryotic cell
Nucleus?
Eukarya
Domain
Plants
Animals
Fungi
Kingdom
The 3 Domains
Classification of Living Organisms (continued)
Taxonomy involves multiple levels in
which particular species are placed into
progressively smaller and smaller
groups of organisms that are more
closely related to each other.
From the most inclusive to least
inclusive: Domain, kingdom, phylum,
class, order, family, genus, species.
Each successive category above
species contains more distinct types of
organisms than the preceding
category.
King Phillip Comes Over For Great Spaghetti
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Scientific Names
Binomial
– First word represents genus.
– Second word is specific epithet or species within the genus.
• Genus species (Ponthera onca)
Universal
Latin-based
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Genomes and Proteomes
Genome:
The complete genetic makeup of an organism.
The genome perform the following functions:
- Act as stable information unit by storing
information that provides a blueprint to create the
organisms characteristics;
-Provide continuity from generation to generation;
- Acts as an instrument of evolutionary change.
Genome can undergo a mutation that may alter
the characteristics of an organism.
Genomics:
Techniques used to analyze DNA
sequences in genomes
Proteomes:
The complete complement of proteins that a cell or organism can make
The genome carries the information to make its proteome
Proteomics:
Techniques used to analyze the proteome of a single species and the comparison of proteomes of
different species
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Biology as a Scientific Discipline
• Science is the observation, identification,
experimental investigation, and theoretical
explanation of natural phenomena
• The Scientific Method is used to test theories
• Some scientists also gather information
❑“Fact-finding mission”
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Understanding biology
Curiosity is the key.
Two general approaches:
1. Discovery-based science (WITHOUT hypothesis)
. Collection and analysis of data without the need for a
preconceived hypothesis
. Goal is to gather information
- Test drugs to look for action against disease
- Sequence genomes and proteomes
. Often leads to hypothesis testing
2. Hypothesis testing/Scientific method
Test the validity of a hypothesis and comprise Five stages:
a. Observations are made regarding natural phenomena.
b. These observations lead to a hypothesis that tries to
explain the phenomena. Remember, a scientific
hypothesis is one that is testable
c. Experimentation is conducted to determine if the predictions are correct.
d. The data from the experiment are analyzed.
e. The hypothesis is accepted (‘verified’) or rejected (‘falsify’) based on results.
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Hypothesis or Theory?
• Hypothesis
❑A proposed explanation for a natural phenomenon
❑Based on previous observations or experiments
❑Hypotheses must make predictions that can be shown
to be correct or incorrect (must be testable)
❑Additional observations or experiments can
support or reject a hypothesis, but a hypothesis is
never really proven
• Example:
❑“Maple trees drop their leaves in autumn because of
shortened hours of sunlight”
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Hypothesis or Theory? continued
◼ Theory
– Broad explanation of some aspect of the natural world
that is substantiated (backed up)by a large body of
evidence
– Allows us to make many predictions
– Also can never be proved true, but due to
overwhelming evidence, may be very likely to be true
◼ Two key attributes of a theory:
1.
2.
Consistent with a vast amount of known data
Able to make many correct predictions
◼ Example
– “DNA is the genetic material”
– Overwhelming body of evidence supports this theory
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Hypothesis Testing
◼ Five stages
1. Observations are made regarding natural
phenomena.
2. These observations lead to a testable hypothesis
that tries to explain the phenomena.
3. Experiments are conducted to determine if the
predictions are correct.
4. The data are analyzed.
5. The hypothesis is accepted or rejected.
◼ These steps comprise the Scientific Method
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Hypothesis testing/Scientific method
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Common features
• Data are often collected in parallel
❑Control and experimental groups
❑Differ by only a single variable
• Data analysis
❑Apply statistical analysis to determine if the control
and experimental groups are different because of
the single variable that is different
❑Are differences statistically significant?
❑If the two sets are found not to be significantly
different, we must reject our hypothesis.
❑If the two sets of data are significantly different, we
accept our hypothesis (though it is not proven)
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Example: Cystic Fibrosis
• Affects about 1 in every 3,500 Americans
• Persons with cystic fibrosis (CF) produce
abnormally thick and sticky mucus that obstructs
the lungs and pancreas
• Average lifespan for people with CF is currently
in their mid- to late 30s
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Example: Cystic Fibrosis
• In 1945, Dorothy Anderson determined that
cystic fibrosis (CF) is a genetic disorder
• In 1989, research groups headed by Lap-Chi Tsui,
Francis Collins, and John Riordan identified
the CF gene
• Discovery-based science, not hypothesis-testing,
found the CF gene
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Hypothesis for function of CF gene
• Hypothesis: The CF gene encodes a protein that
transports chloride ions (Cl-) across the
membrane of cells
• Led to experiments to test normal cells and
cells from CF patients for ability to transport Cl❑CF cells were found defective in chloride transport
❑Transferring a normal CF gene into cells in the lab
corrects this defect
• Chloride transport hypothesis is accepted
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CF Gene Hypothesis
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