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CHAPTER 2
Cells &
Classification
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ORGANIZATION
• Organisms are placed into
domains and kingdoms based
on their cell type, their ability to
make food, and the number of
cells in their bodies.
KINGDOMS
• Archea Bacteria: Unicellular
• Prokaryotes: organisms whose cells lack a nucleus
• Prokaryotes that thrive in very extreme environments
• Hot springs, volcanoes, deep in the oceans, very salty water,
swamps, and intestines of cows
• Eukarya Bacteria: Unicellular
• Eukaryotes: organisms whose cells have a nucleus
• Protists: odds and ends
• Fungi: heterotrophs, absorb nutrients from dead or decaying
organisms
• Plants: multicellular, eukaryotes, autotrophs
• Animals: multicellular, eukaryotes, hetertrophs
CHARACTERISTICS OF LIFE
• Cellular Organization: all living things are
made of cells
• Cell: basic unit of structure and function
in an organism
• Unicellular – made of only one cell
• Multicellular – made of many specialized
cells
WHAT ARE CELLS MADE
OF?
• Chemicals of Life:
• Water – most abundant chemical in cells
• Carbohydrates – energy source
• Proteins and Lipids – building materials of
cells
• Nucleic Acids – genetic material
CELLS USE ENERGY TO:
• Using energy to do things that need to be
done
• Repairing injured parts, movement,
delivering chemicals and food energy,
digesting, reading and understanding
CELLS HELP ORGANISMS
RESPOND
• Response to Surroundings
• Stimulus: a change in an
organism’s surroundings that
causes the organism to react
• Changes in light, sound,
temperature, etc.
• Response: The organism’s
reaction (action or change in
behavior) to the stimulus
CELLS ALLOW US TO GROW
• Growth and Development
• Growth: The process of
getting larger
• Development: process of
change that occurs during an
organism’s life to produce a
more complex organism
CELLS ALLOW US TO
REPRODUCE
• Reproduction
• The ability to produce
offspring that are similar to
the parents
• Sexual: requires 2 parents
(most multicellular)
• Asexual: requires 1 parent –
one organism divides into
two parts (bacteria, yeast,
some plants)
CELLULAR
MISCONCEPTION
Spontaneous Generation
• the MISTAKEN idea that living things
can arise from nonliving sources
Life comes from life !
NEEDS OF LIVING
THINGS
• Water – most
organisms can
only survive a few
days without
water needed for
cell and system
functions
LIVING THINGS
NEED
• Food – organisms need an energy source to live
• Autotrophs: organisms that make their own food using
energy from the sun.
• Auto: self
• Troph: feeder
• Hetertrophs: organisms that cannot make their own food
• Hetero: other (feeding on others)
• Troph: feeder
• Flow of Energy:
• SUN  Plants (auto)  Herbivores (hetero) 
Omivores (hetero)  Carnivores (hetero)
LIVING THINGS NEED
•Living Space –
must provide
organism with
access to food,
water, and shelter
LIVING THINGS NEED
• Stable Internal Environment – keeping
conditions inside the body stable, even
if conditions outside the body change
significantly
• Homeostasis: The maintenance of
stable internal conditions
• i.e. Body temps. stay the same
with weather temp changes.
PROKARYOTIC VS.
EUKARYOTIC
PLANT VS ANIMAL
PARTS TO A CELL
 Rough Endoplasmic Reticulum -•
holds ribosomes to process
proteins
 Ribosomes –
• Process of making proteins to be
sent to other parts of the cell
 Cell membrane –
• outer covering of the cell
PARTS TO A CELL
 Cell wall –
• tough ridged structure
found outside the cell
membrane on plant cells
 Chloroplasts –
• Contain chlorophyll that is
used to capture energy
 Cytoplasm –
• Gelatin like substance that
flows in side the cell
 Central Vacuole –
• food storage in a plant cell
PARTS TO A CELL
 Mitochondrion –
• breaks down food and releases
it as energy
 Nucleolus –
•
Produces Ribosomes
 Nucleus – directs cell activity
 Smooth Endoplasmic Reticulum
• processes Lipids
PARTS TO A CELL
 Golgi bodies –
• Transfers Proteins
 Lysosomes –
• break down damaged or
worn out parts of a cell
 Cytoskeleton –
• framework found inside the
cytoplasm
VIRUSES
 Active attack immediately
 Latent transfer DNA and wait
 Only fight is a vaccine or it runs its
course.
CELL THEORY
All organisms are made of cells
The sell is the basic unit of organization in
an organism
All cells come from cells
MICROSCOPE BASICS
 How to calculate
magnification
• Eye piece (10) x the
objective
DIFFUSION VS OSMOSIS
 Diffusion
•
Is the process of material moving from high concentration to an
area of low concentration
 Osmosis
• The tendency of a fluid, usually water, to pass through a
semipermeable membrane into a solution. Usually driven by
Difusion!