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BACTERIA. Ch. 2.2. Anton van Leeuwenhoek. I. The Bacterial Cell. A. Anton _van_ _Leeuwenhoek_ first discovered bacteria by accident. He made _microscopes_ as a hobby. He liked to look at scrapings from his _teeth_ to look at tiny, _wormlike_ organisms. B. Cell Structures.
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BACTERIA Ch. 2.2
I. The Bacterial Cell • A. Anton _van__Leeuwenhoek_first discovered bacteria by accident. • He made _microscopes_as a hobby. He liked to look at scrapings from his _teeth_to look at tiny, _wormlike_organisms.
B. Cell Structures • 1. _Bacteria_are prokaryotes ( Cells _without_ a nucleus) • 2. The genetic material in bacterial cells is _NOT_found in a nucleus. • 3. Bacteria _lack_many other structures found in cells of eukaryotes (cells _with_a nucleus) • 4. Most bacterial cells are surrounded by a rigid _cell__wall_, which protects the cell.
Cell Structures • 5. Inside the Cell Wall is a _cell__membrane_, which controls what material moves in and out of the cell. • 6. Inside the cell is the _cytoplasm_, a gel-like material. • 7. _Ribosomes_are chemical factories where proteins are produced. • 8. _Genetic_material is found in the cytoplasm. • 9. A bacterial cell may have a _flagella_, a long whip-like structure used for movement. (plural is flagellum)
C. Cell Shapes • 1. Three basic shapes _spherical_, _rodlike_and _spiral_. • 2. It is the _chemical_make-up of the cell that determines the shape of the bacterial cell.
D. Cell Sizes • 1. Bacteria vary greatly in _size_. They are measured in _microns_. • 2. One micrometer is one _millionth_of a meter.
II. Obtaining Food and Energy • A. Bacteria must have a source of _food_and a way of breaking down the food to release its _energy_. • 1. Some bacteria are _autotrophs_(make their own food). • 2. Some bacteria use _energy_from the chemicals in the environment. • 3. Some bacteria are _heterotrophs_(cannot make their own food).
Respiration • B. The process of breaking down food to release energy is called _respiration_.
III. Reproduction • A. When _bacteria_have plenty of _food_, the right temperature and other suitable conditions they thrive and _reproduce_frequently. • B. _Binary__fission_is when 1 bacterial cell becomes 2. • C. _Asexual_reproduction involves only 1 parent and produces offspring identical to the parent.
Reproduction • D. _Sexual_reproduction involves 2 parents who combine their genetic material to produce a new offspring • E. _Conjugation_is a process where 1 bacterial cell transfers genetic material into another bacterial cell. • F. Some bacteria can survive harsh conditions to form an _endospore_, a small rounded thick-walled resting cell that forms inside a bacterial cell.
IV. The Role of Bacteria in Nature • A .Most Bacteria are either _harmless_or _helpful_ (Some cause diseases). • B. Bacteria release _oxygen_into the air to help keep oxygen levels in the air stable. • C. Helpful bacteria make food. List some foods bacteria help make: Cheese, pickles, apple cider, yogurt, sour cream, dried meat,soy sauce, chocolate beverages, sourdough bread. • D. Some bacteria spoil food but refrigerating/heating food _slows_down food spoilage.
Helpful Bacteria • E. _Pasteurization_= food is heated to a temperature that is high enough to kill most harmful bacteria without changing the taste of the food (Named after Louis Pasteur). • F. _Decomposers_are organisms that break down large chemicals in dead organisms into small chemicals. They are “nature’s recyclers”. • G. Some bacteria help to clean up Earth’s _land_and _water_. • H. Bacteria in your _intestines_help you digest food. Scientists use bacteria to make _medicine_.
