Download Levels of Organization

Movement of Materials Through
The Cell Membrane
• Active Transport
• It is an energy-requiring process.
• It enables substances that do not diffuse into
the cell to move against the natural flow.
• That is, materials cross the plasma membrane
against a concentration difference.
Movement of Materials Through
The Cell Membrane
• Three types of active transport
• 1. Individual molecules are carried through
membrane-associated pumps.
• These pumps depend on energy (ATP).
Movement of Materials Through
The Cell Membrane
For example, the sodium-potassium
pump. It ushers out sodium ions (Na+)
and brings in potassium ions (K+)
across the cell membrane.
These pumps are common in nerve and
kidney cells
Sodium Potassium Pump
Movement of Materials Through
The Cell Membrane
• 2. When the particles that want to enter a
cell are large the cell uses a process called
endocytosis
• There are two types of endocytosis.
•
(1) pinocytosis, the cell ingests liquid
(cellular drinking)
•
(2) phagocytosis, the cell takes in solids
(cellular eating)
Movement of Materials Through
The Cell Membrane
Movement of Materials Through
The Cell Membrane
Movement of Materials Through
The Cell Membrane
Movement of Materials Through
The Cell Membrane
Cells are able to remove substances from
the cell by the process of exocytosis.
Movement of Materials Through
The Cell Membrane
Movement of Materials Through
The Cell Membrane
Homeostasis and Cells
• The Cell as an Organism: Single-celled
organisms must be able to carry out all
the functions necessary for life.
• Unicellular organisms maintain
homeostasis, relatively constant internal
conditions, by growing, responding to
the environment, transforming energy,
and reproducing.
• Unicellular organisms include both
prokaryotes and eukaryotes.
Homeostasis and Cells
• Multicellular Life: Cells of multicellular
organisms are interdependent and
specialized.
• The cells of multicellular organisms
become specialized for particular tasks and
communicate with one another to maintain
homeostasis.
Cell Specialization
Cell specialization (also called cellular
differentiation) means that cells are uniquely
suited to perform a particular function.
For example: the air we breathe is filled with
dust, smoke, and bacteria.
Why doesn't all this material collect in the
lungs and clog its passageways?
Cell Specialization
Lining these passageways are special cells
that release mucus which trap the inhaled
particles.
Underneath this layer of mucus is another
group of specialized cells that have cilia.
Cell Specialization
The cilia create a sweeping action thereby
moving the mucus up the trachea to the
pharynx where it is swallowed and removed.
The actions of this mucociliary escalator
keep the most vital passageways in the body
clean and functioning properly.
.
Levels of Organization
In multicellular organisms:
Cells are the first level of organization.
Tissues are the second level of organization.
A tissue is a group of similar cells that
perform similar functions.
Most animals have four main types of tissue:
muscle, nerve, connective, and epithelial.
Levels of Organization
In multicellular organisms:
Organs make up the third level of
organization.
An organ is a group of tissues that work
together to perform a specific function.
Organs are needed because many tasks within
the body are too complicated to be carried out
by just one type of tissue.
Levels of Organization
In multicellular organisms:
Organ systems are the fourth level of
organization.
In many cases, even a complex organ is not
sufficient to complete a series of specialized
tasks. As a result, an organ system, or group of
organs, works together to perform a certain
function.
Examples include the muscular system, the
skeletal system, the nervous system, and the
circulatory system.
Levels of Organization
The organization of the body’s cells into tissues,
organs, and organ systems creates a division of
labor among those cells that allows the organism to
maintain homeostasis.
Levels of Organization
The organization of the cells of the body into
tissues, organs, and organ systems makes
possible a division of labor among those cells
that makes multicellular life possible