Cell Specialization and Organism
Organization
Cell Specialization
 Multicellular
organisms contain a
wide range of different cells. Every cell is
specialized to perform its function as
best as possible. There are many
differences between different cells
specialized for different functions. Cells
may have different shapes, different
contents or different numbers of an
organelle.
Cell Specialization
 In
order for a cell to become
specialized, a process called
Differentiation occurs, where
unspecialized cells (called Stem
Cells) produce cells with specialized
structures.
Cell Specialization
 All
multicellular organisms contain
some form of Stem Cells. These are the
cells that divide to replace damaged or
old tissue, or new cells for growth.
Cell Specialization
 In
plants, Stem Cells are found in
Meristematic Tissue. New cells are
continuously being produced since the
plant continues to grow throughout its
lifetime.
Cell Specialization
 In
humans, early embryos consist of
Stem Cells that can produce any type of
cell. These cells are described as
Totipotent. Stem Cells are also found in
a few places in adults, but these can
only differentiate into a limited number
of types of cell and are called
Multipotent.
Cell Organization
 Cells
that work together to perform a
particular function are organized into
Tissues.

Examples of Tissues include Xylem Tissue,
Ciliated Epithelial Tissue and Parenchyma Tissue.
Cell Organization
 In
animals, Tissues are grouped into four
main categories:
Epithelial Tissue - Linings and layers
 Connective Tissue - Holding structures
together
 Muscle Tissue - Actuation of movement
 Nervous Tissue - Communication via
electrical signals.

Cell Organization
 Tissues
that work together to perform a
larger function are organized into
Organs.

Examples include Leaves, the Heart and
Kidneys.
Cell Organization
 Organs
may be further organized into
Organ Systems, that carry out an
overall function.

For example, the Circulatory System, the Nervous
System, and the Reproductive System.
Put the following in order
from smallest to largest…
 Organs
 Cells
 Organ
Systems
 Tissues
 Organism
Correct Order:
 Cells
 Tissues
 Organs
 Organ
Systems
 Organism