The History of Cell Biology     Chapter 4 – Section 1
The Discovery of Cells• All living things are made up of one or more  cells• A cell is the smallest unit that can carry on...
Robert Hooke• In 1665, Robert Hooke  used a light microscope  to look at a thin slice of  cork• Where does cork come  from?
Robert Hooke• Hooke looked at cork as  well as tree  stems, roots, and ferns• He found that each had  similar little boxes...
Anton van Leeuwenhoek• First person to observe  living cells• In 1673, he was able to  observe  microorganisms in  pond wa...
The Cell Theory• The importance of cells was not recognized  until about 150 years later• Biologists began to organize inf...
The Cell Theory• In 1838, Matthias Schleiden concluded that all  plants were composed of cells• In 1839, Theodor Schwann c...
The Cell Theory• The cell theory states that…  – All living organisms are composed of one or more    cells  – Cells are th...
Developments in Cell Biology
The Cellular Basis of Life• All living things share several basic  characteristics  – Consist of organized parts, obtain e...
Introduction to Cells      Section 4-2
Cell Diversity• Cells are very diverse in terms of  shape, size, and internal organization• A cell’s function influences i...
Cell Shape• The diversity in cell shape reflects the  different functions of cells• A cell’s shape can be simple or comple...
Cell Shape
Cell Size• Cells differ greatly in their sizes   – Nerve cells in a giraffe’s spinal cord can be 2 m     long   – A human ...
Cell Size• The size of a cell is limited by the cell’s surface  area to volume ratio• As a cell grows, its volume increase...
Cell Size• If a cell became very large, there would not be  enough surface area to allow materials to  enter or leave the ...
Cell Size
Cube 2             Cube 1                                          Example                                                ...
Basic Part of a Cell• Three basic features are common to all cell  types – an outer boundary, an interior  substance, and ...
Plasma Membrane (Cell Membrane)• Cell Membrane – the cell’s outer boundary  which covers a cell’s surface and acts as a  b...
Cytoplasm• Cytoplasm – the region of the cell inside the  plasma membrane that includes the fluid, the  cytoskeleton, and ...
Control Center• Cells carry DNA for regulating their functions  and reproducing themselves  – Floats freely in some cells,...
Control Center• Most prominent  structure in eukaryotic  cells• Maintains its shape  with a protein skeleton  called a nuc...
Two Basic Types of CellsEukaryotes           Prokaryotes
Prokaryotes• Organisms that lack a membrane-bound  nucleus and membrane bound organelles• Genetic information (DNA) is oft...
Eukaryotes• Organisms that are made up of one or more  cells and have a nucleus and membrane-  bound organelles• Have a va...
Cellular Organization• Over time, cells began to form groups that  functioned together• Some cells retained the ability to...
Colonies• A colonial organism is a collection of  genetically identical cells that live together in  a connected group• No...
True Multicellularity• Tissue – a group of similar cells and their  products that carry out a specific function• Organs – ...
Cellular Organization
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Chapter 4 ppt

  1. 1. The History of Cell Biology Chapter 4 – Section 1
  2. 2. The Discovery of Cells• All living things are made up of one or more cells• A cell is the smallest unit that can carry on all of the processes of life
  3. 3. Robert Hooke• In 1665, Robert Hooke used a light microscope to look at a thin slice of cork• Where does cork come from?
  4. 4. Robert Hooke• Hooke looked at cork as well as tree stems, roots, and ferns• He found that each had similar little boxes• He named the little boxes cells, because they reminded him of the cubicles that monks lived in
  5. 5. Anton van Leeuwenhoek• First person to observe living cells• In 1673, he was able to observe microorganisms in pond water• He called them “animalcules,” we now call them protists
  6. 6. The Cell Theory• The importance of cells was not recognized until about 150 years later• Biologists began to organize information about cells into a unified understanding
  7. 7. The Cell Theory• In 1838, Matthias Schleiden concluded that all plants were composed of cells• In 1839, Theodor Schwann concluded that all animals were composed of cells• Finally, in 1855, Rudolph Virchow noted that all cells come from other cells• These three observations were combined to form the cell theory
  8. 8. The Cell Theory• The cell theory states that… – All living organisms are composed of one or more cells – Cells are the basic units of structure and function in an organism – Cells come from existing cells
  9. 9. Developments in Cell Biology
  10. 10. The Cellular Basis of Life• All living things share several basic characteristics – Consist of organized parts, obtain energy from their surroundings, perform chemical reactions, change with time, respond to their environment, reproduce, and maintain homeostasis
  11. 11. Introduction to Cells Section 4-2
  12. 12. Cell Diversity• Cells are very diverse in terms of shape, size, and internal organization• A cell’s function influences its physical features
  13. 13. Cell Shape• The diversity in cell shape reflects the different functions of cells• A cell’s shape can be simple or complex depending on the function of the cell• Each cell has a shape that has evolved to allow the cell to perform its function effectively
  14. 14. Cell Shape
  15. 15. Cell Size• Cells differ greatly in their sizes – Nerve cells in a giraffe’s spinal cord can be 2 m long – A human egg cell is about the size of a period at the end of a sentence – Most cells are only about 1/500 the size of a period at the end of a sentence – http://learn.genetics.utah.edu/content/begin/cell s/scale/
  16. 16. Cell Size• The size of a cell is limited by the cell’s surface area to volume ratio• As a cell grows, its volume increases much faster than its surface area• This is important because material needed by a cell (such as nutrients and oxygen) and wastes produced by a cell (such as carbon dioxide) must pass into and out of the cell through its surface
  17. 17. Cell Size• If a cell became very large, there would not be enough surface area to allow materials to enter or leave the cell quickly enough to meet the cell’s needs• Therefore, most cells are microscopic in size
  18. 18. Cell Size
  19. 19. Cube 2 Cube 1 Example 4 cm2 cmCube 1 Cube 2Surface Area of Cube 1= Length x Width x Surface Area of Cube 2= Length x Width x 6 Sides ______________ Surface Area of Cube 2= 4 cm x 4 cm x 6 =Surface Area of Cube 1= 2 cm x 2 cm x 6 = ________ ______________Volume of Cube 1= ______ x width x __________ Volume of Cube 2= length x width x height Volume of Cube 2 = 4 cm x 4 cm x 4 cmVolume of Cube 1 = 2 cm x 2 cm x 2 cm Volume of Cube 2 = 64 cm3Volume of Cube 1 = ____________ Surface area to Volume ratio= Surface area/volumeSurface area to Volume ratio= Surface area/volume Surface Area to Volume ratio of Cube 2= 96 cm2/64 cm3 = ____________Surface Area to Volume ratio of Cube 1=24 cm2/8 cm3 = __________
  20. 20. Basic Part of a Cell• Three basic features are common to all cell types – an outer boundary, an interior substance, and a control region
  21. 21. Plasma Membrane (Cell Membrane)• Cell Membrane – the cell’s outer boundary which covers a cell’s surface and acts as a barrier between the inside and the outside of a cell• All materials enter or exit through the cell membrane
  22. 22. Cytoplasm• Cytoplasm – the region of the cell inside the plasma membrane that includes the fluid, the cytoskeleton, and all of the organelles except for the nucleus – Cytosol – part of the cytoplasm that includes molecules and small particles but not membrane- bound organelles
  23. 23. Control Center• Cells carry DNA for regulating their functions and reproducing themselves – Floats freely in some cells, other cells keep the DNA in a nucleus• Most of the functions of a eukaryotic cell are controlled by the nucleus
  24. 24. Control Center• Most prominent structure in eukaryotic cells• Maintains its shape with a protein skeleton called a nuclear matrix
  25. 25. Two Basic Types of CellsEukaryotes Prokaryotes
  26. 26. Prokaryotes• Organisms that lack a membrane-bound nucleus and membrane bound organelles• Genetic information (DNA) is often located in a part of the cell called the nucleoid• Usually smaller and less complex than eukaryotes
  27. 27. Eukaryotes• Organisms that are made up of one or more cells and have a nucleus and membrane- bound organelles• Have a variety of organelles, which are well- defined, intracellular bodies that perform specific functions for the cell• Generally larger and more complex than prokaryotic cells
  28. 28. Cellular Organization• Over time, cells began to form groups that functioned together• Some cells retained the ability to live outside a group• Others became dependent on each other for survival
  29. 29. Colonies• A colonial organism is a collection of genetically identical cells that live together in a connected group• Not truly multicellular because few cell activities are coordinated
  30. 30. True Multicellularity• Tissue – a group of similar cells and their products that carry out a specific function• Organs – groups of tissues that perform a particular job in an organism• Organ System – group of organs that accomplish related tasks• Organism – several organ systems combined
  31. 31. Cellular Organization

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