Cell Structure

1
Cell Structure Function

• Introduction to Cells
• Eukaryotic Cells
• Prokarytoic Cells

2
Introduction to Cells

• History
• Robert Hooke (1600s) first described cells in
  thin sections of cork that he examined under
  microscope
• Robert Brown (1820) first to describe that a
  nucleus seemed to be associated with all cells
  (at least eukaryotic cells)

3
Introduction to Cells

• History (continued)
• Theodore Schwann Matthias Schleiden (1839)
  advanced cell theory
• All organisms are composed of cells
• The cell is the basic unit of life
• All cells arise from preexisting cells

4
Introduction to Cells

• Cell Types
• Prokaryotic
• Eukaryotic
• Sizes
• Prokaryotic 0.2 to 2.0 microns
• Eukaryotic 10 to 100 microns

5
Introduction to Cells

• Size Determinants
• Cell surface to volume relationships govern cell
  size
• The smaller the cell the more efficiently
  materials can be transported into and within the
  cell
• Cell must also be large enough to deal with
  information and metabolic requirements

6
Introduction to Cells
7
Introduction to Cells

• Common Components to All
• Plasma membrane phospholipid bilayer that
  controls movement of substances into and out of
  cells
• Ribosomes site of protein synthesis note
  ribosomes have both RNA protein
• Cytoplasm matrix on interior of cell consisting
  of water soluble proteins and other materials
• Nuclear material DNA/Protein complex that
  stores information
• Prokaryotic circular
• Eukaryotic linear and in chromosomes

8
Eukaryotic Cells

• Eukaryotic Cells
• Larger than prokaryotic
• More complex than prokaryotic
• All multicellular organisms composed of
  eukaryotic cells
• Eukaryotic cells composed of many internal
  structures called organelles

9
Eukaryotic Cells

• Endosymbiotic theory (Lynn Margullis 1967)
• Evidence
• Mitochondria chloroplasts replicate via binary
  fision
• Mitochondria chloroplasts have circular DNA
• Mitochondria chloroplasts have 70S (bacterial
  ribosomes)
• Mitochondria chloroplasts start protein
  synthesis in the same way as prokaryotic cells
• Mitochondria chloroplasts DNA sequences of
  similar genes show greater relationships to
  prokaryotic genes

10
Eukaryotic Cells

• Nucleus
• Mitochondria
• Chloroplast
• Endoplasmic reticulum (R S)
• Golgi body

• Lysosome
• Peroxisome
• Centrioles
• Vacuoles
• Flagella cilia

11
Eukaryotic Cells
12
Eukaryotic Cells
13
Eukaryotic Cells

• Nucleus
• Regulates growth and reproduction of cell
• Contains DNA and chromosomes
• Nucleolus
• Ribosomal RNA synthesis

14
Eukaryotic Cells

• Mitochondria
• Energy production in cell
• Contains its own DNA (circular)

15
Eukaryotic Cells

• Endoplasmic reticulum (rough and smooth)
• Site of protein synthesis in cells
• Start of protein export process
• Connected to nuclear pores and Golgi body

16
Eukaryotic Cells

• Golgi body
• Sorting center for proteins in cell
• Produces vesicles which fuse with plasma membrane

17
Eukaryotic Cells

• Lysosome
• Only in animal cells
• Production of intracellular digestive enzymes
• Involved with phagocytosis

18
Eukaryotic Cells

• Peroxisomes
• Peroxisomes are small rounded organelles found
  free floating in the cell cytoplasm.
• Contain at least 50 enzymes and are separated
  from the cytoplasm by a lipid bilayer single
  membrane barrier.
• Produce hydrogen peroxide which is toxic but is
  rapidly degraded by catalase

19
Eukaryotic Cells

• Flagella cilia
• Involved with motility of cells
• Composed of microtubules

20
Eukaryotic Cells

• Vacuoles
• Found only in plants
• Large central organelle in plant cells
• Regulates water in plant cells

21
Eukaryotic Cells

• Chloroplast
• Site of photosynthesis in plant cells
• Has own DNA (circular)
• Found only in plants

22
Eukaryotic Cells

• Endosymbiotic theory (Lynn Margullis 1967)
• Evidence
• Mitochondria chloroplasts replicate via binary
  fision
• Mitochondria chloroplasts have circular DNA
• Mitochondria chloroplasts have 70S (bacterial
  ribosomes)
• Mitochondria chloroplasts start protein
  synthesis in the same way as prokaryotic cells
• Mitochondria chloroplasts DNA sequences of
  similar genes show greater relationships to
  prokaryotic genes