The Cellular Structure of Eukaryotic Cells

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The Cellular Structure of Eukaryotic Cells
You need your microbiology textbook!

• Chapter 5

You need your microbiology textbook!
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Objectives

• Identify the structure of a typical cell
• Define the function of each part of the
  eukaryotic animal cell
• Describe the processes that transport materials
  in and out of a cell

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Cells

• Basic structural unit of living things
• Eukaryotes
• Cells that have true nucleus held by a nuclear
  membrane. Has chromosomes and divides by mitosis.
• Prokaryotes
• Unicellular organism lacking a true nucleus and
  nuclear membrane. Its genetic material consists
  of a single loop of DNA and no chromosomes

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Cells

• Cytologists specialize in the pathology of the
  cell, whose changes in internal structures give
  important clues as to the cause or source of
  disease

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Cells

• Organelles specialized structures found with
  the cytoplasm of cells, each with a specific
  function

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Cell Structure

• Nucleus
• Control center for all cell activity. Contains
  the chromosomes and DNA.
• Cell Membrane
• A thin layer of plasma-like material that
  surrounds the cytoplasm and the organelles. It
  is located between the cell wall and the
  protoplasm of the cell and allows molecules to
  pass in and out of the cell

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Cell Membrane
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Cell Structure

• Cytoplasm
• Gel-like protoplasm of a cell that surrounds the
  nucleus. It is bound by the cell membrane and
  holds the organelles in place
• Nucleolus (and Ribosomes)
• A rounded body in the nucleus of most cells that
  is the site of ribosomal RNA synthesis

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Cell Structure

• Endoplasmic Reticulum
• Network of folded membranes in the cytoplasm of a
  cell that transport materials throughout the cell
• Mitochondria
• Rod-shaped organelle of cells that is responsible
  for cellular respiration and energy production

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Cell Structure

• The Golgi Apparatus
• Packages and wraps proteins for export out of the
  cell
• Lysosomes
• Aids in the digestion of proteins by secreting
  digestive enzymes

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Cell Structure

• Pinocytic Vesicles
• Pockets or folds in the cell membrane that allow
  large molecules such as proteins and lipids to be
  taken into the cell

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Movement across the cell membranes

• Diffusion
• Osmosis
• Filtration
• Active transport
• Phagocytosis
• Pinocytosis

A passive process requires no energy to function
An active process that requires an energy source
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Diffusion

• Process of spreading out or movement of molecules
  through a substance. The larger the molecules
  the slower the movement.

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Osmosis

• Passage of a solvents molecules through a
  selective permeable membrane from a solution of
  lesser solute concentration to a solution of
  greater solute concentration

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Filtration

• Process of a fluid passing through a filter

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Active transport

• When cells must move materials in an opposite
  direction - against a concentration gradient. It
  requires Energy
• Phagocytosis
• "cell eating" - extensions off cytoplasm surround
  a particle and package it within a food vacuole
  and then the cell engulfs it.

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Active transport

• Pinocytosis
• the process of taking up liquid from the
  surrounding environment. Tiny pockets form along
  the membrane, fill with liquid, and pinch off