Bacteria (Chapter 23)
Section 1 Prokaryotes
Section 2 Biology of Prokaryotes
Section 3 Bacteria and Humans
Section1 Objectives:
1.
2.
3.
4.
5.
Explain the phylogenetic relationships between the domains Archaea, Bacteria, and Eukarya.
Identify three habitats of archaea.
Describe the common methods used to identify bacteria.
Identify five groups of bacteria.
Explain the importance of nitrogen-fixing bacteria for many of Earth’s ecosystem.
Two Major Domains: _________________ and ___________________
* _____________________________ are single-celled organisms that do not have a membrane-bound nucleus,
and can live in nearly every environment on Earth.
* Although tiny, prokaryotes differ greatly in their _______________ ______________, their modes of
nutrition, and their _________________________.
* Based on genetic _________________________, prokaryotes are grouped in two domains: Domain Archaea
and Domain ____________________.
Domain Archaea
* One of the ways in which archaea differ is the make up of their _________ _________. Archaeal cells walls
do __________ contain peptidoglycan.
-___________________________ is a protein-carbohydrate complex found in bacterial cell walls that
make their cells walls rigid.
* Archaea differ in the types of _________________ in their cell membrane. Also, archaeal genes do not
contain introns.
* Archaeal Groups (3 groups)
-Archaeal groups include methanogens, halophiles, and thermoacidophiles.
1. ____________________________________ convert hydrogen gas and carbon dioxide into
________________. They can be found in the __________________________ of organisms such as cattle and
termites.
2. ____________________________________ are “salt-loving” archaea that live in very salty environments
such as the Great Salt Lake and the ___________ __________.
3. ______________________________________ live in very hot, acidic environments, such as the _________
_______________________ of Yellowstone National Park. Some thermoacidophiles live at temperatures up to
110°C (230°F) and at a pH of less than 2.
Domain Bacteria
* Bacteria occur in many ______________ and ________________. Most bacteria have one of three basic
shapes: rod-shaped, sphere-shaped, or spiral-shaped.
* Rod-shaped bacteria are called __________________ (singular, bacillus). An example of bacilli is Escherichia
coli.
* Sphere-shaped bacteria are called ___________________(singular, coccus). An example of cocci is
Micrococcus luteus.
* Spiral shaped bacteria are called ______________________ (singular, spirillum). An example of spirilla
bacteria includes Spirillum volutans
* Cocci that form chains similar to a ______________ of beads are called _______________________________.
* Cocci that form ________________similar to a bunch of grapes are called _____________________________.
* Gram Stain
-Most species of bacteria are classified into two categories based on the structure of their cell walls as
determined by a technique called the _______________ _________________.
-Gram-positive bacteria have a thick layer of peptidoglycan in their cell wall, and they appear
_______________________under a microscope after the Gram-staining procedure.
-Gram-__________________________ bacteria have a thin layer of peptidoglycan in their cell wall, and
they appear reddish-pink under a microscope after the Gram-staining procedure.
Important Bacterial Groups
*Bacteria are also classified by their ___________________________ properties and evolutionary relationships.
1. Proteobacteria
-Proteobacteria are one of the _________________________ and most diverse groups of bacteria, and
contain several subgroups that are extremely diverse.
-Members of this group include bacteria of the genus Rhizobium, the genus Agrobacterium, and the
bacterium __________________________ _____________.
2. Gram-Positive Bacteria
-Not all of the bacteria in this group are Gram-positive. Biologists place a few species of Gramnegative bacteria in this group because these species are __________________________ similar to Grampositive bacteria.
-Members of this group include the streptococcal species, Clostridium botulinum, Bacillus anthracis,
and members of the genus Mycobacteria
*Antibiotics are chemicals that inhibit the growth of or kill other microorganisms. ________________________
and ______________________________________ are examples of antibiotics that are used medicinally.
3. Cyanobacteria
-Cyanobacteria use ________________________________ to get energy from sunlight, and make
carbohydrates from water and carbon dioxide. During this process, they create ____________________ as a
waste product.
-Once called blue-green algae, cyanobacteria are now known to be ________________________
because they lack a membrane-bound nucleus and chloroplasts.
4. Spirochetes
-Spirochetes are Gram-negative, spiral-shaped bacteria that move by means of a corkscrew-like
rotation. Some are ___________________________.
-Spirochetes can live _____________________ or as pathogens. Pathogenic spirochetes include
Treponema pallidum, the causative agent of syphilis, and Borrelia burgdorferi, which causes Lyme
disease.
5. Chlamydia
-Gram-negative coccoid pathogens of the group Chlamydia live only __________________ animal
cells. The cell walls of chlamydia do _________ have peptidoglycan. Chlamydia trachomatis causes the
sexually transmitted infection called chlamydia.
Section 2 Objectives:
1.
2.
3.
4.
5.
Describe the internal and external structure of prokaryotic cells.
Identify the need for endospores.
Compare four ways in which prokaryotes get energy and carbon.
Identify the different types of environments in which prokaryotes can live.
List three types of genetic recombination that prokaryotes use.
Structure and Function
* The major structures of a prokaryotic cell include a cell wall, a cell membrane, cytoplasm, ribosomes, and
sometimes a capsule, pili, endospores, and flagella.
1. Cell Wall
-Most prokaryotes have a cell wall. Bacterial cell walls contain __________________________________.
Archaeal cell walls do not have peptidoglycan; instead, some contain _________________________________,
a compound made of unusual lipids and amino acids.
2. and 3. Cell Membrane and Cytoplasm
-Bacterial and archaeal cell membranes are lipid bilayers that have _________________________. However, the
lipids and proteins of archaeal cell walls differ from those of bacterial cell walls.
-The _______________________________ is a semifluid solution that contains ribosomes, DNA, small organic
and inorganic molecules, and ions.
4. DNA
-Prokaryotic DNA is a single closed _______________ of double-stranded DNA attached at one point to the cell
membrane.
-Along with a single main chromosome, some prokaryotes have _________________________, which are
small, circular, self-replicating loops of double-stranded DNA.
5. and 6. Capsules and Pili
-Many bacteria have an outer covering of polysaccharides called a _________________________ that protects
the cell against drying, pathogens, or harsh chemicals.
-Pili are short, ________________________________ protein structures on the surface of some bacteria that
help bacteria connect to each other and to surfaces, such as those of a host cell.
7. Endospores
-Some Gram-positive bacteria can form a thick-coated, resistant structure called an endospore when
environmental conditions become _____________________.
Prokaryotic Movement
-Many prokaryotes have long _______________________ that allow the prokaryotes to move toward food
sources or away from danger.
Nutrition and Metabolism
* Prokaryotes obtain nutrients either from the nonliving environment or by utilizing the products or bodies of
living organisms.
-_______________________________obtain carbon from other organisms.
-_______________________________ obtain their carbon from CO2.
-_______________________________ get energy from chemicals in the environment.
Prokaryotic Habitats
* Different prokaryotic species live in different environments.
* Temperature requirements range from 0°C to 110°C.
* Most prokaryotic species grow best at a _________________________ pH.
Reproduction and Recombination
*Genetic recombination in bacteria can occur by the following three ways:
1. __________________________________ (taking in DNA from the outside environment)
2. __________________________________(exchanging DNA with other bacteria via pili)
3. __________________________________ (transmission of bacterial DNA via viruses).
Section 3 Objectives:
1.
2.
3.
4.
Describe the ways in which bacteria can cause disease in humans.
Explain how a bacterial population can develop resistance to antibiotics.
Identify reasons for recent increases in the numbers of certain bacterial infectious diseases.
Identify ways of preventing a foodborne illness at home.
Bacteria and Health
*Human diseases may result from _____________________ or _______________________ produced by
bacteria or from the destruction of body tissues.
*Antibiotics and Antibiotic Resistance
-A mutation in the DNA of a single bacterium can confer ___________________________ to an antibiotic.
-Cells with the mutant gene have a selective advantage when the antibiotic is present.
-Mutant cells take over the population when the normal cells __________.
*Emerging Infectious Diseases Caused by Bacteria
-The number of certain bacterial diseases has _________________________ because of the increase in the
number of antibiotic resistant bacteria, the movement of people into previously untouched areas, and
__________________________travel.
*Food Hygiene and Bacteria
-Foodborne illnesses can be avoided by selecting, storing, cooking, and handling food ___________________.
-Frequent hand washing in hot, soapy water is also very important.
Bacteria in Industry
*Many species of bacteria are used to produce and process different foods, to produce industrial chemicals, to
mine for minerals, to produce _____________________________, and to clean up chemical and oil spills.
*Biologists have learned to harness bacteria to recycle compounds in a process called
_____________________________________, which uses bacteria to break down pollutants.