This document discusses the structure and functions of bacteria. Bacteria are prokaryotic cells that lack nuclei and have genetic material floating in the cytoplasm. They have cell walls, cell membranes, cytoplasm, and ribosomes. Bacteria can obtain food through photosynthesis, chemosynthesis, or consuming other organisms. They reproduce through binary fission or conjugation. Bacteria play important roles in nature such as producing oxygen, aiding food production, and serving important functions in health, medicine, and the environment such as decomposition. However, some bacteria can also cause diseases in humans and other organisms.

1. Bacteria
Chapter 2 Lesson 2

2. Cell Structure
 Prokaryotic – genetic material is free in
the cytoplasm rather than enclosed in a
nucleus as in a eukaryotic cell
 Cell Wall
 Cytoplasm
 DNA

3. 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

4. Energy & Reproduction
 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.

5. Bacteria’s Role 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.

6. 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