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Bacteria
Chapter 2 Lesson 2
What are bacteria?
 Prokaryotic – genetic material is free in
the cytoplasm rather than enclosed in a
nucleus as in a eukaryotic cell
 Cell Wall
 Cytoplasm
 DNA
Functions of Cell Parts
 Cell Wall – protects the cell & provides structure &
support
 Cell Membrane – controls what materials come in
and out of the cell.
 Cytoplasm – fluid in the cell containing organelles
and genetic material and allows structures to move
within the cell
 Ribosomes – organelles which produce proteins
 Genetic material – DNA contains the information
for all the cell functions
How do bacteria get food, get
energy, and reproduce?
 Obtaining food:
 Autotrophs using photosynthesis or chemosynthesis
 Heterotrophs consume other organisms & often serve as
decomposers in the environment
 Reproduction
 Binary fission: asexual reproduction in which one bacteria divides to
form two identical cells.
 Each cell receives a copy of genetic information
 Conjugation: sexual reproduction in which one bacteria transfers
some DNA to another bacteria.
 Results in new combinations of genes
 Endospores
 Form when conditions are not favorable for bacterial growth
 A thick-walled cell that can withstand extreme conditions for many
years until conditions improve.
What is the role of bacteria in
nature?
 Oxygen production:
 autotrophic bacteria that use photosynthesis supply oxygen to the
atmosphere
 Food production:
 cheese & yogurt are examples of foods produced with the help of
bacteria
 Health/Medicine:
 bacteria in your digestive tract help to digest your food and provide
vitamins your body needs.
 Bacteria are also used to produce medicine like insulin.
 Environment:
 bacteria help clean up oil spills and are natures recyclers.
 decomposers break down dead organisms and return those
compounds into the soil.
 Nitrogen fixing bacteria live near plant roots and convert nitrogen gas
to the nitrogen plants need to grow.
Disease
 Bacteria can cause disease in humans, other
animals, and plants
 Common diseases in Humans:
Strep throat: Streptococcus pyogenesoften If
left untreated, becomes scarlet fever and can
affect the health of your heart
Pneumonia: Streptococcus pneumoniae Attacks
the alveoli (air sacs) in your lungs
Tuberculosis: aggressive bacteria that attacks
your lungs. Treating TB is difficult
Food poisoning: E. coli, Salmonella, Listeria are
common causes