Name: Date:

Biology 11: Prokaryotes

Microbiology (Domain Bacteria and Archaea) (Chapter 27)

Describe the basic structure of a prokaryotic cell Diversity - use examples to illustrate diversity of the domain Bacteria with respect to the following:

form, distribution, motility, ecological role, nutrition, and human diseases Differentiate among fermentation, aerobic respiration, and photosynthesis in monerans Contrast the ways in which bacterial decomposers and parasites obtain their food Demonstrate sterile technique while preparing a streak plate Evaluate the effectiveness of various antibiotics, disinfectants, and antiseptics on bacteria cultures Explain processes by which bacteria adapt to become resistant to antibiotics Give examples of the beneficial roles of bacteria Demonstrate the presence and variety of micro-organisms on surfaces around the school Examine the structure and function of the three different types of organisms in Domain Archaea.

Text Pages: 319 to 329 *This is required reading

What are Prokaryotes and why do We Care?

-In the table below list some major differences between Prokaryotic and Eukaryotic Cells:

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Characteristics Prokaryotes Eukaryotes

Size

Cell Wall

Organelles

Nucleus

Genetic Material

-Prokaryotes represent the earliest forms of life that existed on Earth, with the Geologic Record indicating that they were present almost 4 bya!

-Today, most people associate Prokaryotes with Bacterial Pathogens but it is important to remember that there are many times more beneficial or benign prokaryotes than there are harmful ones.

-Here are some important roles of Prokaryotes in our world:

a) Ancient photosynthetic prokaryotes are responsible for the creation of our atmospheric oxygen, allowing aerobic life to develop.

b) The hundreds of bacteria species living on/in our bodies perform functions necessary for humans to live! e.g. The bacteria in our intestines release nutrients from food molecules that we can’t digest and also supply us with essential vitamins!

c) Act as decomposers by breaking down dead animal and plants remains, releasing their nutrients back into the environment so that they can be used again.

*In short, Prokaryotes made it possible for all other forms of life to exist on Earth and continue to do so today!

Why are Prokaryotes so Successful?

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-The collective biomass of Prokaryotes is at least 10 times as much as that of all Eukaryotes and they are also able to survive in habitats that are too cold, hot, salty, acidic or alkaline for any Eukaryote.

-What characteristics make them so successful?

External Features

a) Cell Shape:

-3 basic shapes, useful in ID.

-Allows for survival in particular environments.

-Draw and describe variations of each basic prokaryotic cell shape:

b) Cell Wall

-The cell wall functions as:

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-There are two different types of Prokaryote cell walls:

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-Many Prokaryotes have cell walls that are covered by

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capsules, a _____________________________________

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c) Projections

-Flagella ______________________________________

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-Fimbriae/pili _________________________________________________________________________

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d) Rapid Adaptation to Changes in Environment

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-Prokaryotes can reproduce quickly in ideal environmental conditions: Some species of can create a new generation in under 20 minutes by ____________________.

-Is the binary fission method of reproduction sexual or asexual? If this is true, how is genetic variation created in Prokaryotic cells?

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ii) Conjugation

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http://www.hhmi.org/biointeractive/animations/conjugation/conj_frames.htm

iii) Transduction

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iv) Transformation: A bacterium picks up DNA released into the environment by dead bacteria.

-The experiment by Griffith (1928) shows bacteria being transformed by bacterial genes they are absorbing from their environment.

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Why is genetic variation important? _______________________________________________________

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-If the environment becomes too extreme, an endospore can form: __________________________________________________________________

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*Watch the Endospore Formation Animation

-Some endospores can remain dormant for centuries. Not even boiling water kills most of these resistant cells. To sterilize laboratory equipment, microbiologists use an autoclave, a pressure cooker that kills endospores by heating to a temperature of 121°C (250°F) with high-pressure steam. The food-canning industry uses similar methods to kill endospores of dangerous bacteria such as Clostridium botulinum, the source of the potentially fatal disease ___________________.

e) High Nutritional Diversity

-Energy Source:

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-Carbon Source:

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-Mode of nutrition:

i) Photoautotroph ______________________________________________________________________

ii) Photoheterotroph ____________________________________________________________________

iii) Chemoautotroph ____________________________________________________________________

iv) Chemoheterotroph __________________________________________________________________

-Diversity of nutritional modes means that prokaryotes can obtain energy and carbon in almost any habitat!

-In which of the categories above would you be classified? _____________________________________

Prokaryotic Domains

Domain Archaea

-Some archaea possess unusual proteins and other molecular adaptations to living in extreme environments and, as such, are called extremophiles:

a) Halophiles

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b) Thermophiles

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c) Methanogens

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-Many Archaea also live in non-extreme environments.

-Little is known about Archaea as bacteria have thus far been the subject of most prokaryotic research.

Domain Bacteria

-Genetic analysis (molecular biology) has resulted in bacteria being divided into five groups. Take your own brief notes on these groups.

a) Proteobacteria (Gram Negative)

b) Gram Positive Bacteria _______________________________________________________________

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c) Cyanobacteria ______________________________________________________________________

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d) Chlamydias ________________________________________________________________________

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e) Spirochetes _________________________________________________________________________

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Disease Causing Bacteria

-Bacteria cause diseases by producing either:

a) Exotoxins __________________________________________________________________________

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b) Endotoxins_________________________________________________________________________

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-Below are some bacterial disease outbreaks and methods of infection:

Helpful Bacteria

-Many bacteria are helpful to the rest of life on Earth and even necessary for the existence of other organisms. Examine the examples provided and complete the notes below.

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-Nitrogen Cycling:

-The roots in the photo exhibit root nodules containing nitrogen-fixing bacteria. Nodules are like fertilizer factories for the plant.

-What do the bacteria living in the nodules gain from this association with plants? What type of symbiosis is this?

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-Conduct your own research to discover some beneficial and important bacteria that benefit humans.

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Bacteria and Antibiotic Resistance (text 272)

-What is an antibiotic and where have they been harvested from?

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-How does a population of bacteria adapt to become resistant to antibiotics?

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-http://www.scq.ubc.ca/attack-of-the-superbugs-antibiotic-resistance/ is an article worth reading if you want to learn more about antibiotic resistance in bacteria.

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