Download Cell and Molecular Biology

Cell and Molecular Biology
The Origin of Life
Behrouz Mahmoudi
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Aristotle (384 –322
BC)
• Proposed the theory of
spontaneous generation
• Also called abiogenesis
• Idea that living things
can arise from nonliving
matter
• Idea lasted almost 2000
years
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Proposed Life-Generating Environments
• Reducing Atmosphere + Lightning
(methane hydrogen, ammonia, water)
Urey and Miller experiment.
• Hydrothermal Vents (hydrogen sulfide +
carbon dioxide + heat in the deep ocean)
• Primitive Clays Crystal structures in clays
which could spontaneously catalyze the
formation of certain prebiotic polymers.
• Bubble theory
• Exobiology Life came here from elsewhere
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Micelle
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Biologists have formulated a list of
characteristics by which we can recognize
living things
Cellular Organization
Reproduction
Metabolism (Obtain and Use Energy)
Homeostasis
Heredity
Responsiveness
Information
processing
Growth and Development
Adapt Through Evolution
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Cell theory.
a) Life exists only in cells
b) The cell is the smallest unit of life.
c) The continuity of life has a ellular
basis.
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Unicellular Organisms
Multicellular Organisms
Entire organism is
made up of one single
cell
The organism is made up
of many cells
Bacteria and protists
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Cells have specialized
functions within the
organism
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Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
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Reproduction is the process of producing
new organisms of the same type.
Asexual
Reproduction
A single parent
organism
reproducing by
itself
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Sexual
Reproduction
Two different
parent organisms
contribute genetic
information
Involves the
combination of male
and female sex cells
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Asexual
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Sexual: a new genetic
combination
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Living organisms need energy
to grow, develop, repair
damage, and reproduce
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Anaboli
sm
The process of building up complex
substances from simpler substances
 Building up cells and cellular
components
 Photosynthesis
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Catabolis
The processm
of breaking down
complex substances into simpler
substances to release energy
 Digestion
 Cellular Respiration
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Metabolis
The total ofm
all chemical
reactions in an organism
 Anabolism + Catabolism =
Metabolism
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A stable state of conditions in
the body that are necessary for
life
Body temperature
Blood volume
pH balance
Water balance
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Genes carry hereditary information
Genes are composed of DNA
Heredity is the reason children resemble
their parents
Mutations
change DNA
code and can be
passed from
generation to
generation
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Organisms react to stimuli:
Light
An example is a plant’s
leaves and stems growing
toward light
Temperature
Odor
Sound
Gravity
Heat
Water
Pressure
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