(1) Order (2) Reproduction (3) Growth and development (4) Energy processing (7) Evolutionary adaptation (6) Regulation (5) Response to the environment All forms of life share common properties

The Cell Theory Cells are the basic unit of structure and function in an organism All cells come from prexisting cells  Robert Hooke (17th century) –Coined the phrase ‘cells’  Anton van Leeuwenhoek (later 17th century) –Observed microscopic organisms; organisms can be comprised of just a single cell  Schleiden (1830s) –All plants are made of cells  Schwann (1839) –All animals are made of cells

10 m 1 m Human height Length of some nerve and muscle cells Chicken egg 0.1 m 1 cm Frog egg 1 mm 100 µm Most plant and animal cells 10 µm Nucleus 1 µm Most bacteria Mitochondrion Smallest bacteria Viruses 100 nm 10 nm Ribosomes Proteins Lipids 1 nm Small molecules Atoms 0.1 nm Unaided eye Light microscope Electron microscope Cells: A Sense of Scale Most cells and their structures are too small to view with the naked eye. Scanning EM of Enteric bacteria on villi of small intestine

Microscopes reveal the world of the cell  Light microscope - 1,000x magnification, limited resolution –Magnification is the increase in the apparent size of an object. –Resolution is a measure of the clarity of an image -- it is the ability of an instrument to show two close objects as separate.  Transmission electron (TEM) - detail of interior structures  Scanning electron (SEM) - surface structures ‘3D image’ –Electron microscopes DO NOT allow observations of living specimens. © 2012 Pearson Education, Inc.

1 µm Scanning electron microscopy (SEM) Cilia Longitudinal section of cilium TransmissionelectronMicroscopy(TEM) Cross section of cilium Scanning electron microscopy (SEM) Light Microscopy

2 Basic Cell Types: Prokaryote and Eukaryote  Bacteria and archaea are prokaryotic cells. –Prokaryotes have no nucleus and no true organelles.  Eukaryotic cells = protists, plants, fungi, animals  All cells have: –a plasma membrane –one or more chromosomes (DNA) –Ribosomes –cytoplasm –Only Eukaryotic cells have a –membrane-bound nucleus and –number of other organelles.

Hydrophilic region Hydrophobic region Carbohydrate side chain Structure of the plasma membrane Hydrophilic region Phospholipid Proteins Outside of cell Inside of cell 0.1 µm TEM of a plasma membrane

Prokaryotic Cell Structure Fimbriae Ribosome Nucleoid Plasma membrane Cell wall Capsule Flagella Bacterial chromosome A typical rod-shaped bacterium  Unicellular  Cell Wall surrounds plasma membrane –Composed of lipids, carbohydrates and protein –Peptidoglycan (mix of protein and carbohydrates) –NO Cellulose (plants cells) –Provides structure and support  Nucleiod region –One large circular chromosome that is attached to one area of the plasma membrane  Flagella (Flagellum) –Used for directed movement –Rotate like propellors

Endospore Flagella Fimbriae Capsule Tonsil cell Bacterium

A typical rod-shaped bacterium a. b. c. d. e. f. g. Label The Following Structures: h.

Concept Check  The three domains of life described by biologists today include the bacteria, the archaea, and the eukarya (all other forms of life). What is the basic difference between the eukarya or eukaryotes and the prokaryotes (archaea and bacteria)? a)The prokaryotes do not have a plasma membrane surrounding the cell. b)The prokaryotes use RNA and not DNA to pass on the genetic message. c)The interior of the cell of eukaryotes is divided by internal membranes into specialized compartments. d)The eukaryotes engage in cellular metabolism while the prokaryotes do not. © 2012 Pearson Education, Inc.

Answer  The three domains of life described by biologists today include the bacteria, the archaea, and the eukarya (all other forms of life). What is the basic difference between the eukarya or eukaryotes and the prokaryotes (archaea and bacteria)? –The interior of the cell of eukaryotes is divided by internal membranes into specialized compartments. © 2012 Pearson Education, Inc.

 Images generated by the Hubble telescope or the planetary probes like Voyager telescope give us a very limited view of the universe. Likewise, looking at cells under a light microscope is limited by the ability to resolve cellular parts. Which of the following cell parts are visible under a light microscope? –ribosomes –large macromolecules –microtubules –mitochondria—just barely © 2012 Pearson Education, Inc. Interpreting Data

 Images generated by the Hubble telescope or the planetary probes like Voyager telescope give us a very limited view of the universe. Likewise, looking at cells under a light microscope is limited by the ability to resolve cellular parts. Which of the following cell parts are visible under a light microscope? –mitochondria—just barely © 2012 Pearson Education, Inc. Answer