Parts are Parts! And together they are life

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Parts are Parts! And together they are life

• Cell Anatomy and Function

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Cells are the smallest unit that can meet the 5
characteristics of life.

• 1. they are organized.
• 2. they respond to environmental
• stimuli.
• 3. they metabolize.
• 4. they reproduce.
• 5. they are adapted to the environment

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The cell is the smallest unit of life.

• The cellular level is important because essential
  activities of life occur in cells and disease
  originates there.
• The CELL is the smallest structure capable of
  maintaining life and reproducing life.

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Cyto means cell, so

• CYTOLOGY is the study of cells.
• Cytogenetics is the study of the chromosomes
  within the cell
• Cells have many parts some of the parts are the
  organelles, cytoplasm other structures each
  with a specific function within the cell

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• Living cells are about 60 water. Cells vary
  tremendously in length - from 2 micrometers
  (1/12,000th of an inch) in the smallest cells to
  over a meter in some nerve cells.

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Form Function

• There are many different shapes of cells in the
  body as well. Red blood cells are disc-shaped
  nerve cells have thread-like extensions smooth
  muscle cells are shaped like toothpicks and
  epithelial cells are cube-like.

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Structures - main ones

• plasma membrane or cell membrane
• nucleus
• cytoplasm
• organelles
• fibers
• inclusions
• mitochondria

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A TOUR OF THE CELL

• Internal structures or organelles are in two
  groups
• Group 1 membranous organelles
• Membranous organelles, as the name implies, are
  cellular structures made of phospholipid
  bilayers.
• Group 2 non-membranous or protein organelles

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A Scanning EM of a cell

• Method of movement

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Group 1 includes

• Nucleus
• Endoplasmic Reticulum (rough and smooth)
• Golgi Apparatus
• Mitochondria
• Vacuoles
• In plants Chloroplasts

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Nucleus

• Largest structure in a cell
• Usually spherical membrane shell that houses DNA
  and makes RNA for use in directing protein
  synthesis. By controlling what proteins are made,
  the nucleus controls most cellular functions.

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• The cell nucleus is a remarkable organelle
  because it forms the package for our genes and
  their controlling factors. It functions to
• Store genes on the chromosomes - Organize
  genes into chromosomes to allow cell division.

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The nucleus also

• Transport regulatory factors gene products via
  nuclear pores
• Produce messages ( messenger Ribonucleic acid
  or mRNA that code for proteins Produce
  ribosomes in the nucleolus Organize the
  uncoiling of DNA to replicate  key genes

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Endoplasmic reticulum (ER)

• "Maze-like" network of membrane often spanning
  out from the nucleus. The rough ER is dotted with
  ribosomes and is often an industrial complex for
  protein production. The smooth ER, a site where
  some of the proteins produced do their job, is
  where detoxification, materials processing and
  lipid synthesis occur.

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• With
• Rough ER
• ribosomes
• Smooth ER
• Without
• ribosomes

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Golgi apparatus

• (also Golgi complex/body) - Packaging and special
  processing of molecules (mainly proteins) for
  export out of the cell.

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Mitochondria

• Nicknamed "the powerhouse of the cell," they are
  membranous energy transducers that convert
  molecular energy from one molecule to another
  (usually from sugars, lipids, and amino acids to
  ATP).

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Chloroplasts (in plant cells)

• A collection of membranous structures that
  convert sunlight and low-energy molecules into
  carbohydrates.

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Vacuole

• Typically a large bubble of membrane used for
  storage inside a cell.

http//content.answers.com/main/content/img/McGraw
Hill/Encyclopedia/images/CE725300FG0010.gif
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• Animal
• Lots of small
• Vacuoles
• Plant
• 1 large central
• vacuole

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And a host of small players

• Vesicle - Small storage bubble of membrane.
• Lysosome - Vesicle or small vacuole containing
  digestive enzymes.

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Phagocytosis and lysosome in action

• http//www.as.wvu.edu/caldwell/101fig_lysosome.jp
  g
• http//www.as.wvu.edu/caldwell/101diagrams.htm

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Group 2

• The protein-based organelles are very different,
  but no less important in their support roles in
  the cell.

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Protein based

• Cytoskeleton - Network of protein fibers and
  tubes that support and move the cell.
• Flagella cilia - contractile proteins important
  for moving the cell (i.e. sperm) or moving other
  substances in a multicellular organism (i.e.
  ciliated epithelium of the human respiratory
  tract).

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• Finally, there are miscellaneous organelles who's
  structure is less well defined, or otherwise do
  not fall into the preceding categories.
• Ribosomes - Debated by some as to whether it is
  an organelle or a just a simple (even if elegant)
  mixture of rRNA and proteins worksites for
  protein synthesis.
• Centro some - Area (containing the centrioles in
  animal cells) responsible for directing many
  aspects of cell division.

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http//fig.cox.miami.edu/cmallery/150/cells/organ
elle.htm
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Remaining organells

• Nucleolus - Area within the nucleus most closely
  associated with RNA production.
• Microvilli - Folds in the plasma membrane to
  increase surface area (for absorption, transport,
  etc.).
• Cell wall - "Polysaccharide container" associated
  with plant cells (and fungi).

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They all work together

• Fig 4.

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Similar but different
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Differences between plant and animal cells

• There are many different types of cells.  One
  major difference in cells occurs between plant
  cells and animal cells.  While both plant and
  animal cells contain the structures discussed
  above, plant cells have some additional
  specialized structures. 

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Support

• Many animals have skeletons to give their body
  structure and support.  Plants do not have a
  skeleton for support and yet plants don't just
  flop over in a big spongy mess.  This is because
  of a unique cellular structure called the cell
  wall.  The cell wall is a rigid structure outside
  of the cell membrane composed mainly of the
  polysaccharide cellulose. 

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Plant Cell

• The cell wall gives the plant cell a defined
  shape which helps support individual parts of
  plants.  In addition to the cell wall, plant
  cells contain an organelle called the
  chloroplast.  The chloroplast allow plants to
  harvest energy from sunlight. 

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• See the cell wall? And the chloroplasts?

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Plant Cell

• Specialized pigments in the chloroplast
  (including the common green pigment chlorophyll)
  absorb sunlight and use this energy to complete
  the chemical reaction
•  6 CO2 6 H2O energy (from sunlight)  C6H12O6
  6 O2

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Plant Cell Characteristics

• Plant cells have a cell wall and a large central
  vacuole. In the mature plant, the central vacuole
  may occupy 50-90 of the cell interior. It stores
  amino acids, sugars, water. ions, and wastes. The
  vacuole enlarges during growth and greatly
  increases the cell's outer surface area. The
  cytoplasm is forced into a very narrow zone
  between the central vacuole and the plasma
  membrane.

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• Plant cells may also have chloroplast or other
  plastids. Chloroplasts are oval or disk shaped.
  They are bounded by a double membrane, and are
  critical to the process of photosynthesis. They
  have stacked disks (grana), pigments and enzymes
  which trap sunlight energy to form ATP. Sugars
  are formed in the fluid substance (stroma)
  surrounding the stacks. Pigments such as
  chlorophyll (green) confer distinctive colors to
  the chloroplasts.

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Animal Cell Characteristics

• Between animal cells is a matrix or meshwork that
  holds animal cells and tissues together and
  influences how the cells will divide and
  metabolize.
• Complexity is the method to hold cells together

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Plant vs Animal Cell

• Plant cells have a cell wall, but animal cells do
  not. In animals the cell membrane is the outside
  boundary,
• Plant cells have chloroplasts, but animal cells
  do not.
• Plant cells generally have a more rectangular
  shape because the cell wall is more rigid. Animal
  cells have a round or irregular shape because
  they do not have a cell wall.
• Both plant and animal cells contain a cell
  membrane.

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