BIOL125_Ch4 Text Notes

BIOL125_Ch4 Text Notes - BIOL 125 (Microbiology) Text Notes...

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BIOL 125 (Microbiology) Text Notes Chapter 4: Survey of Prokaryotic Cells and Microorganisms 1. CHARACTERISTICS OF CELLS AND LIFE a. All cells tend to be spherical, cubical, or cylindrical; and the cytoplasm is surrounded by a cell membrane. b. Most cells fall into one of two fundamental different lines: prokaryotic cells and eukaryotic cells. i. Eukaryotic cells are found in animals, plants, fungi, and protists. They contain complex organelles, which are enclosed by membranes, and carryout specific activities involving metabolism, nutrition, and synthesis. ii. Prokaryotic cells are found only in the bacteria and Archaea. They have no nucleus or other organelles. c. What is Life? i. The characteristics most inherent to life are: 1) Heredity and reproduction. 2) Growth and development. 3) Metabolism, including cell synthesis and the release of energy. 4) Movement and/or irritability. 5) Cell support, protection, and storage mechanisms. 6) Capacity to transport substances into and out of the cell. ii. Heredity and Reproduction. 1) Hereditary material of an organism lies in its genome (a complete set of genetic information). a) The genome is composed of elongated strands of DNA packed in to chromosomes. i) In eukaryotic cells, the chromosomes are located within a nuclear membrane. They also carry a different type of chromosome within their mitochondria. ii) In prokaryotic cells, the DNA occurs on a special type of chromosome not enclosed by a membrane. 2) Most eukaryotic cells reproduce both sexually and asexually. a) Many eukaryotic cells engage in mitosis , an orderly division of chromosomes that usually accompanies cell division. 3) Prokaryotic cells reproduce primarily by binary fission , a process of cell splitting equally into two. They have no mitotic apparatus, nor do they reproduce sexually. File: 80306990c7aabdeb08e16b47872689642404d3ef.doc Updated 8/14/09
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Text Notes Chapter 4 Page 2 iii. Metabolism: Chemical and Physical Life Processes. 1) Cells synthesize proteins using ribosomes. a) In eukaryotes, ribosomes are dispersed throughout the cell or inserted into membranous sacs called endoplasmic reticulum (ER) . b) Prokaryotes have smaller ribosomes scattered throughout the cytoplasm because they do not have an ER. 2) Eukaryotes generate energy by chemical reactions in the mitochondria. a) Photosynthetic eukaryotes contain chloroplasts, which contain the pigment for photosynthetic reactions. 3) Prokaryotes use the cell membrane to generate energy. a) Photosynthetic reactions in prokaryotes occurs in the cell membrane, not in chloroplasts. iv. Movement and Irritability. 1) Motility – self-propulsion. a) Eukaryotes move by locomotor organelles such as cilia, flagella, or pseudopods. b)
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This note was uploaded on 08/12/2009 for the course BIOL 125 taught by Professor Dr.sujathapamula during the Spring '09 term at San Jacinto.

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BIOL125_Ch4 Text Notes - BIOL 125 (Microbiology) Text Notes...

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