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CELLS

CELLS. CELLS – the basic unit of life!. I. Basic HISTORY:. Every living thing-from the tiniest bacterium to the largest whale-are made of one or more cells! Before the seventeenth century, no one knew that CELLS existed. . I. Basic HISTORY:.

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CELLS

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  1. CELLS

  2. CELLS – the basic unit of life!

  3. I. Basic HISTORY: • Every living thing-from the tiniest bacterium to the largest whale-are made of one or more cells! • Before the seventeenth century, no one knew that CELLSexisted.

  4. I. Basic HISTORY: • Most cells are too smallto be seen with the unaided eye. • Not discovered until after the invention of the microscopein the early 17th century.

  5. II. IMPORTANT SCIENTISTS: • A Dutch drapery storeowner Anton von Leewenhoek, became the FIRST person to OBSERVE and DESCRIBE MICROSCOPIC ORGANISMS and LIVING CELLS.

  6. II. IMPORTANT SCIENTISTS: • 1665: the English Scientist Robert Hooke used a microscope to examine a thin slice of corkand described it as consisting of "a great many little boxes".  It was after his observation that Hooke called what he saw "cells". They looked like "little boxes" and reminded him of the small rooms in which monks lived. So he called them "cells".

  7. Illustration of cork drawn by Robert Hooke:

  8. II. IMPORTANT SCIENTISTS: • 1824: the French scientist Henri Dutrochet, concluded that plantand animal tissue were always made up of cells • 1831: Robert Brown named the nucleus

  9. II. IMPORTANT SCIENTISTS: • In 1838: German Botanist Matthias Schleiden concluded that all plantsare made of cells • 1839: German Zoologist Theodor Schwann reported that animals are also made of cells

  10. II. IMPORTANT SCIENTISTS: • 1845: Felix Dujardin- studied the living cell and noted it contained a material called protoplasm. • In 1855: German Physician Rudolf Virchow induced that ALL cells come from preexisting cells.

  11. II. IMPORTANT SCIENTISTS: • The COMBINED work of Schleiden, Schwann, and Virchow make up what is now known as the modern CELL THEORY.

  12. III. The Cell Theory Consists of 3 Principles: • All living things are composed of one or more cells. • Cells are the basic units of structureandfunction in an organism. • Cells come only from thereproduction of existing cells.

  13. IV. TWO TYPES of CELLS: 1. EUKARYOTES = cell that contain a nucleus and other membrane-bound organelles ~Ex: plants, fish, mammals, insectsand humans

  14. IV. TWO TYPES of CELLS: 2. PROKARYOTES = cell that lacksa nucleus and other membrane-bound organelles. ~Ex: unicellularorganisms such as bacteriaand their relatives

  15. V. CELL DIVERSITY: • Not all cells are alike.  • Cells within the same organism show enormous diversity in size, shape, and internal organization.  • Your body contains at least 200 different cell types!

  16. VI. CELL SIZE: • A few types of cells are large enough to be seen by the unaidedeye.  • Female egg is the largest cell in the body, and can be seen without the aid of a microscope. • Most cells are visible only with a microscope.

  17. VI. CELL SIZE: • Most cells are small for 2 reasons: 1. Cells are limited in size by the RATIObetween their outer surface area and their volume.  • As a cell’s size increases, its volume increases much faster than its surface area.  • (see picture on the next slide!)

  18. VI. CELL SIZE: 2. The cell’s nucleus (the brain) can only control a certain amount of living, active cytoplasm.

  19. VII. CELL SHAPE: • Variety of shapes. • The shape of the cell depends on its function

  20. VII. CELL SHAPE: • Ex: Nerve cells that carry information from your toes to your brain are long and threadlike. • Ex: Blood cells are shaped like round disk that can squeeze through tiny blood vessels

  21. VIII. CELLULAR ORGANIZATION: • Multicellular organisms are made up of many cells, each of which is specialized to perform a distinct function. • Digestion, movement, respiration, filtering, etc… • Individual cells DO NOT carry out ALL life functions, but rather depend on each other

  22. VIII. CELLULAR ORGANIZATION: • Tissue = a group of cells functioning together to perform and activity • Ex: muscle and nerve tissues • Ex: Plant tissues = stem and root • Organs = groups of two or more tissues that function together • Stomach, leaf of a plant • Cooperation among organs makes life functions within an organism efficient

  23. VIII. CELLULAR ORGANIZATION: • SUMMARY:Cells  Tissues  Organs

  24. Study the organelles!

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