Cell Structure and Function

1
Cell Structure and Function

• Modern Biology Chapter 4
• Biology Exploring Life
• Sections 6.1, 6.4, 6.5, 6.6

2
Microscopy

• Magnification v. resolution
• Microscopes
• Compound light microscope (LM)
• Electron microscopes (EM)
• Transmission electron microscope (TEM)
• Scanning electron microscope (SEM)
• Scanning tunneling electron microscope (STM)

3
Cells

• First observed by Robert Hooke in 1665
  (corkdead)
• Living first observed by Anton van Leeuwenhoek in
  1673
• Surrounded by a cell membrane and, in some cases,
  a cell wall
• Cell Theory
• All living things are composed of one or more
  cells.
• Cells are the basic units of structure and
  function in an organism.
• Cells come only from the reproduction of existing
  cells.

4
Cellular Composition

• Unicellular organisms
• Consist of just one cell
• Examples
• Bacteria
• Some protists (ex. Euglena, Paramecium)
• A few fungi (ex. yeast)
• Multicellular organisms
• Made of many cells
• Examples
• Plants
• Animals
• Some protists and most fungi

5
Cell Types

• Prokaryotic
• No nucleus
• Contain no membrane-bound organelles
• Much smaller and more primitive
• Bacteria only
• Eukaryotic
• True nucleus
• Contain membrane-bound organelles
• Relatively large and more advanced
• All organisms except bacteria

6
Organelles

• Little organs
• Membrane-bound compartments that isolate specific
  cellular functions from one another
• Division of labor within a cell
• Surrounded by jellylike cytosol (cytosol
  organelles cytoplasm)

7
Nucleus

• Plural nuclei
• Brains of a cell
• Site of DNA storage, replication, and
  transcription

8
Ribosomes

• Not membrane-bound
• Protein factories
• Site of protein synthesis
• May be free in cytoplasm or attached to
  endoplasmic reticulum

9
Endoplasmic Reticulum (ER)

• Rough ER
• Ribosomes attached
• Site of protein synthesis and transport
• Smooth ER
• No ribosomes attached
• Site of lipid synthesis and transport

10
Golgi Apparatus

• Warehouses of a cell
• Where molecules are prepared for shipment to
  other parts of the cell or out of the cell
• Packaging in the form of membrane sacs called
  vesicles

11
Mitochondria

• Singular mitochondrion
• Powerhouses of a cell
• Site of cellular respiration
• Where energy is released from the digestion of
  glucose and other food molecules

12
Lysosomes

• Stomachs of a cell
• Enclose hydrolytic enzymes for the digestion of
  molecules, old organelles, and ingested cells

13
Plant Cell Organelles

• Plastids
• Chloroplastschlorophylls and accessory pigments
  for photosynthesis
• Chromoplastsother pigments
• Leucoplastsstarch
• Vacuoles
• Store water, enzymes, metabolic wastes, and toxins