The Cell Theory

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The Cell Theory
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The Cell Theory

• All living things are composed of cells
• Cells are the basic unit of structure and
  function of living things
• All cells are produced from other cells

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The Cell Theory

• All living things are composed of cells
• Plants and Animals are alive, therefore they are
  made up of cells
• Unicellular organisms are one celled organisms
• Ameoba (animal)
• Algae (plant)
• Multicellular organisms are organisms with many
  cells
• Cats (animal)
• Oak Tree (plant)

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The Cell Theory

• Cells are the basic unit of structure and
  function of living things
• Cells are organized into tissues
• Tissues are organized into organs
• Organs are organized into organ systems
• Organ systems are organized into the organism

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CellsgtTissuegtOrgangtOrgan SystemgtOrganism
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The Cell Theory

• All cells are produced from other cells
• One cells grows and divides
• Now you have 2 cells
• 2 cells grow and divide
• Now you have 4 cells
• 4 cells grow and divide
• Now you have 8 cells
• New cells are needed for an organism to grow and
  also to replace cells that die

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Closure Question

• What are the 3 statements made by The Cell
  Theory?
• 1. All living things are made of cells.
• 2. Cells are the basic unit of structure and
  function in living things.
• 3. Cells come from other cells.

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Diversity of Cellular Life
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Cells

• Are the simplest form of life
• Chemical elements organized into cells become
  living matter.
• All organisms are made-up of cells
• All the substances of an organism are the
  products of its cells

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Life is Cellular

• Some things are only one cell(unicellular)
• Some have many cells (multicellular)

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Unicellular or Multicellular

• SINGLE CELL ORGANISM

• MULTI-CELL ORGANISM

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Cells are small for 2 Reasons

• Reason 1
• Limited in size by the RATIO between their Outer
  Surface Area and Their Volume. 
• A small cell has more SURFACE AREA than a large
  cell for a GIVEN VOLUME OF CYTOPLASM. 

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Unicellular Organisms may be

• Prokaryotic Eukaryotic

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Remember? What does the Eukaryotic Cell have
that Prokaryotic Cells does not?
No nucleus
Has a nucleus
No organelles
Has organelles
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Colonial Organisms Video

• A colony of single-celled organisms is a colonial
  organism. It's likely that early colonial
  organisms were the first evolutionary step from
  single celled life to multicellular species.

Synura (above) and rotifer egg.  
Synura Three individual colonies. Ref synura01.
Volvox releasing daughter colonies. Ref volvox01
Three Scenedesmus. Ref scened00
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Colonial Organisms

• The difference between a multicellular organism
  and a colonial organism is that individual cells
  from a colony can, if separated, survive on
  their own, while cells from a multicellular
  life form (e.g., liver cells) cannot.

Filamentous Algae
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Colonial Organisms

• In a multicellular organism the cells have become
  specialized and taken on specific jobs to help
  out the whole organism
• In a colonial organism,there is little
  difference between cells.

Volvox carteri, a colonial freshwater alga. The
small dots are regular cells and the large ones
are asexual reproductive cells
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Cell Differentiation

• Cell differentiation- When cells take on a
  different shape, size, and chemistry, suitable
  for a certain function during development.
• Cells vary in size, shape, and internal
  components
• The variety of cell shapes include round, flat,
  long, rectangle, etc.
• Some cells have different extensions from the
  cell membrane

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Cell Specialization

• cell specialization- The characteristic of having
  separate roles for each type of cell in a
  multicellular organism the cells is
  specifically designed for a certain function it
  has a certain purpose or job.
• The size and shape of a cell is related to its
  function

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Division of Labor

• division of labor- A more efficient way of
  getting jobs done in a multicellular organism
  because the different tasks are dispersed to
  different cells, each of which is specialized to
  do that job.
• The organelles that make up a certain cell are
  also determined by the specific functions carried
  out by the cell

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Levels of Organization

• levels of organization- A system of hierarchy in
  which a group of things are arranged in order of
  rank, complexity, or size. Each group is made up
  of smaller parts and/or are a part of a larger
  group. (example- cells form tissues, which form
  organs, etc.)

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Levels of Organization

• Cell
• Tissue
• Organ
• Organ system

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Cells

• Many
• different types
• of cells are
• formed during
• embryonic
• development.

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Cells Continued

• Cells occur in many different shapes and sizes so
  they can perform many different functions.

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Tissue

• Many different cells work together to form a
  tissue.

Cartilage
Muscle
Nerves
Fat
Skin
Bone
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Organ

• Many tissues working together form an organ

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Organ System

• Each organ
• system is made up
• of several different
• organs that work
• together and
• enable the system
• to do its job.

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Eleven Organ Systems

• Circulatory
• Digestive
• Endocrine
• Excretory
• Integumentary
• Lymphatic

• Muscular
• Nervous
• Reproductive
• Respiratory
• Skeletal

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Review of Organization

• Cells have a special job to do (i.e. cell from
  intestine)

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Review of Organization

• 2. Tissues a group of similar cells that work
  together to carry out a special job (i.e. group
  of lining cells in intestine)

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Review of Organization

• 3. Organ a group of tissues that work
  together to do a job (i.e. small intestine)

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Review of Organization

1. Organ system a group of organs that work
   together to do a certain job (i.e. digestive
   system)

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Review of Organization

• 5. Organism all organ systems working
  together (i.e. digestive, respiratory,
  circulatory, etc.)

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Review of Organization
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Review of Organization

• Some organisms are made up of only one cell but
  they have all the features of living things
• The parts of their cell still work together
• Other organisms have organs and organ systems
  like humans
• Systems work together to keep us alive