483 Lecture Notes - Lecture 16: Endospore, Democratic Senatorial Campaign Committee, Purple Bacteria
14 Jun 2018
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IBiology I Lecture Notes 8 Kingdom Monera References (Textbook - pages 362-372, ab
Manual - pages 89-94) Major Characteristics 1. The Kingdom Monera includes bacteria and
blue-green algae 2. All are microscopic and unicellular 3. All are prokaryotic - their
genetic material (DNA) is not organized into a well- defined nucleus 4. Cells lack many
organelles found in the eukaryotic cells of members of other Kingdoms 5. Nutrition is mostly by
absorption (heterotrophic) from a host cell or organism, however, some are photosynthetic or
chemosynthetic (recall these aTt! 2 types o£QJ4totrophs) Reproduction is asexual by fISsion
orfragmentation (recall tnito.fis i.f nudear division and bacteria do "ot h(llle a "uc/e.us)
Classification 1. The Kingdom Monera can be divided into 2 Divisions (SchiZJ}phyta and
Cyanophyta) A. Division is a taxon similar in rank to the taxon called a Phylum B.
Inpractice, many botanists use the term Division rather than Phylum, whereas many
zoologists use the term Phylum rather than Division C. The 5 Kingdom ClassifICation
System (see Lab Manual, pages 85-88) used as a standard for General Biology classes at
DSCC uses both terms 2. Division Scbizopbyta A. Includes close to 2,000 different
kinds of bacteria B. Occur in nearly all types of environments on earth 3. Division
Cyanopbyta A. Includes the cyanobacteria or blue-green algae B. Cyanobacteria are
normally larger than bacteria of Division Schizophyta c. They possess chlorophyll and carry
on photosynthesis Structure of Bacterial Cell (See Handout ofFigure - Generalized Body Plan
ofBacterium) 1. Structural Features A. Nucleoid - the central region of the cell
where DNA isfound B. DNA 1) Bacteria have a singular, circular loop of DNA 2)
A bacterial cell may also contain a plasmid - not sbown on Handout of Generalized Body Plan
ofBacterium 3) A plasmid is a extra-chromosomai ring ofaccessory DNA in the
cytoplasm of bacterial cells C. Ribosomes 1) Are usually smaller than the ribosomes of
eukaryotic cells 2) Have a similar function - protein synthesis D. Cell wall 1) Like plant cells,
bacteria have a cell wall 2) The cell wall surrounds the plasma membrane 3) It is semi-rigid and
permeable 4) [t helps maintain cell shape and resists rupturing of cell 5) The cell wall contains
peptidoglycan molecules 6) Gram positive (+) bacteria have a thick layer ofpeptidoglycan and
turn purple when exposed to a Gram Stain Procedure 7) Gram negative (-) bacteria have a thin
layer ofpeptidoglycan and turn pink when exposed to a Gram Stain Procedure E. Plasma
membrane - a lipid bi-layer like in eUkaryotic cells F. Capsule I) Sometimes called a
slime layer 2) A polysaccharide layer that protects bacteria G. Appendages (2 types in
bacteria) J) Flagella a) Long appendages b) Rotate to provide propulsion c) Some bacteria
have only one, other bacteria may have many d) Are used for locomotion 2) Pili a) Hollow,
hair-like projections b) ~lade ofprotein c) Used to attach to other cells 2. Tbree Common
Shapes ofBacteria A. Coccus - round shape o B. Bacillus - rod shape or c. Spirillum -
spiral shape 3. Formation of Endospores A. Some very deadly bacteria produce
endospores B. When faced with unfavorable environmental conditions a portion ofthe
cytoplasm and a copy of the chromosome will dehydrate andform an endospore c. In some
bacteria the original bacterial ceU deteriorates and the endospore is released D. The
endospore can tolerate harsh conditions and survive for long periods of time E.
Whenfavorable conditions return, endospores re-hydrate and become a typical bacterial cell
again F. anthrax endospores have been known to survive 1,300 years and still germinate
into infectious bacteria Reproduction of Bacteria I. Bacteria reproduction is asexual 2. Cell
division occurs but it is NOT mitosis 3. Mitosis is the division ofthe cell nucleus and
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