THE CELL

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THE CELL
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INTRO TO CELLS

• CELLS ARE BASIC UNITS OF ORGANISMS
• CELLS CAN ONLY BE OBSERVED UNDER A MICROSCOPE
• BASIC TYPES OF CELLS
• ANIMAL PLANT BACTERIAL

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Microscopes and Cells

• 1600s.
• Anton van Leeuwenhoek first described living
  cells as seen through a simple microscope.

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ANTOINE VAN LEEUWENHOEK

• Using his handcrafted microscopes he was the
  first to observe and describe single celled
  organisms, which he originally referred to as
  animalcules, and which we now refer to as
  microorganisms. He was also the first to record
  microscopic observations of muscle fibers,
  bacteria, spermatozoa and blood flow in
  capillaries (small blood vessels).

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Microscopes and Cells

• Robert Hooke used the first compound microscope
  to view thinly sliced cork cells.

• Compound scopes use a series of lenses to magnify
  in steps.
• Hooke was the first to use the term cell.

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Microscopes and Cells

• 1830s.
• Mathias Schleiden identified the first plant
  cells and concluded that all plants
• made of cells.

- Thomas Schwann made the same conclusion about
animal cells.
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Twenty years later in 1855 Rudolf Virchow
proposed an important extension of cell theory
that "All living cells arise from pre-existing
cells". ("Omnis cellula e celula") This statement
has become what is known as the "Biogenic
law". This idea flew in the face of current
doctrine. It implied that there was no
spontaneous creation of cells from non-living
matter.
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CELL THEORY

• PROPOSED BY SCHLEIDEN, SCHWANN AND VIRCHOW
• ALL ORGANISMS ARE COMPOSED OF ONE OR MORE CELLS
• THE CELL IS THE BASIC UNIT OF LIFE IN ALL LIVING
  THINGS
• ALL CELLS COME FROM EXISTING CELLS

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NUMBER OF CELLS

• ORGANISMS MAY BE
• UNICELLULAR
• COMPOSED OF ONE CELL
• MULTICELLULAR
• COMPOSED OF MANY CELLS THAT MAY ORGANIZE

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Two Basic Cell Types

• 1) Prokaryote
• Lacks internal compartments.
• No true nucleus.
• Most are single-celled (unicellular) organisms.
• Examples bacteria

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Two Basic Cell Types

• 2) Eukaryote
• Has several internal structures (organelles).
• True nucleus.
• Either unicellular or multicellular.
• unicellular example yeast
• multicellular examples
• plants and animals

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TWO TYPES OF CELLS

• PROKARYOTES

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PROKARYOTES

• ALSO CALLED BACTERIA
• WORLDS SMALLEST CELLS
• NO NUCLEUS
• DNA IS ONE LONG CIRCULAR SHAPED BAND
• MOST COVERED BY CELL WALL
• NO MEMBRANE BOUND ORGANELLES
• PROBABLY FIRST TYPE OF CELLS ON EARTH

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EUKAROYTES
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EUKARYOTES

• ALL LIVING THINGS THAT ARE NOT BACTERIA
• CELLS HAVE A NUCLEUS AND MANY MEMBRANE BOUND
  ORGANELLES
• MANY DIFFERENT CHEMICAL PROCESSES CAN OCCUR AT
  ONCE
• DNA IS LINEAR

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PROKARYOTE EUKARYOTE

• NO NUCLEUS
• NO MEMBRANE-BOUND ORGANELLES
• CIRCULAR DNA
• BACTERIA

• NUCLEUS
• MEMBRANE BOUND ORGANELLES
• LINEAR DNA
• ALL OTHER CELLS

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Complete the web with four characteristics of
cells.
All organisms -living things- are made of cells.
Cells do the jobs that keep organisms alive.
Cells
Cells are the smallest part of a living thing.
These cells are like tiny building blocks.
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CELL SIMILARITIES

• CELLS COME IN ALL SHAPES AND SIZES AND PERFORM A
  VARIETY OF FUNCTIONS, BUT THEY ALL HAVE THE
  FOLLOWING THINGS IN COMMON
• CELL MEMBRANE
• DNA
• CYTOPLASM AND ORGANELLES

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CELL MEMBRANE
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CELL MEMBRANE

• Protective layer around cell
• Regulates interactions between cell and its
  environment
• Controls what enters and exits

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CYTOPLASM
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CYTOPLASM

• Gelatin-like substance constantly flowing
• Many important chemical reactions occur in it and
  most of lifes processes occur in it
• Contains a framework called cytoskeleton helps
  maintain shape

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CELL WALL
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CELL WALL

• CELLS OF PLANTS, ALGAE, FUNGUS, AND SOME BACTERIA
  HAVE HARD CELL WALL
• PROVIDES STRENGTH AND SUPPORT TO CELL MEMBRANE
• CELLS OF MUSHROOMS, MOLD AND YEAST HAVE CELL WALL
  MADE OF CHEMICAL SIMILAR TO COVERING OF INSECTS

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NUCLEUS
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NUCLEUS

• LARGEST AND MOST VISIBLE ORGANELLE IN EUKARYOTES
• NUCLEUS MEANS KERNEL OR NUT
• COVERED BY MEMBRANE
• CONTROL CENTER OF CELL(DIRECTS ALL CELL
  ACTIVITIES)
• STORES DNA (LONG THREADLIKE MATERIAL THAT
  CONTAINS CODE FOR CELL ACTIVITIES)
• HAS INFO ON HOW TO MAKE PROTEINS

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RIBOSOMES
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RIBOSOMES

• MAKES THE PROTEINS WHICH ARE MADE UP OF AMINO
  ACIDS USED BY THE BODY FOR GROWTH AND REPLACEMENT
  AND REPAIR OF BODY CELLS
• NOT MEMBRANE BOUND
• SOME FLOAT FREELY OTHERS ARE ATTACHED TO THE ER

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ENDOPLASMIC RETICULUM
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ENDOPLASMIC RETICULUM(ER)

• MAKES LIPIDS AND OTHER MATERIALS FOR USE INSIDE
  AND OUTSIDE OF CELL
• BREAKS DOWN DRUGS AND OTHER CHEMICALS THAT COULD
  DAMAGE A CELL
• INTERNAL DELIVERY SYSTEM OF CELL MOVES
  SUBSTANCES FROM ONE PART OF CELL TO ANOTHER
• SMOOTH ER (NO ATTACHED RIBOSOMES) ROUGH ER
  (RIBOSOMES ATTACHED)

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MITOCHONDRIA

• ENERGY FOR THE CELL (ATP) IS PRODUCED AT THE
  MITOCHONDRIA (BREAKS DOWN FOOD INTO CO2 AND
  WATER)
• WE BREATHE AIR TO MAKE SURE OUR MITOCHONDRIA HAVE
  OXYGEN THEY NEED TO MAKE ATP
• HIGHLY ACTIVE CELLS LIKE THE HEART AND LIVER HAVE
  THOUSANDS
• OTHERS HAVE ONLY A FEW

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CHLOROPLASTS

• CONTAINS CHLOROPHYLL ( ONLY IN PLANTS AND
  BACTERIA)
• MAKES FOOD IN PLANTS CONVERTS SUNLIGHT, CARBON
  DIOXIDE AND WATER INTO SUGAR

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GOLGI BODIES

• STACKED, FLATTENED MEMBRANES
• SORT PROTEINS, PACKAGE THEM, AND DELIVER THEM
  AROUND THE CELL

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VACUOLES

• STORE WATER AND OTHER LIQUIDS
• SOME PLANTS WILT WHEN THEIR CELL VACUOLES LOSE
  WATER
• VACUOLES ARE USUALLY THE LARGEST ORGANELLE IN A
  PLANT CELL

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LYSOSOMES

• CONTAIN ENZYMES
• DESTROY WORN OUT OR DAMAGED ORGANELLES
• GET RID OF WASTE MATERIALS
• PROTECT CELL FROM FOREIGN INVADERS

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