Download Biology 11 Name: Blk: ________Date:______ Bacteria Worksheet

Biology 11
Name: ______________________
Blk: ________Date:__________
Bacteria Worksheet
Complete the following based on the type of biological classification:
Traditional five-kingdom system:
1. Monera
2. Protista
3. Fungi
4. Plantae
5. Animalia
Six kingdom system:
1. Eubacteria
2. Archaebacteria
3. Protista
4. Fungi
5. Plantae
6. Animalia
Three-domain system:
1. Bacteria
2. Archaea
3. Eukarya
The three basic shapes of bacteria are
1. Rod Shaped, which are called bacilli
2. Spherical shaped, which are called Cocci
3. Spiral Shaped, which are called Spirilla
Growth patterns:
The prefix which indicates that bacteria are growing in chains is Strepto.
The prefix which indicated that bacteria grow in pairs is Diplo.
The prefix which indicates that bacteria grow in clumps is Staphylo.
Cell wall:
What is the structural difference between gram-negative and gram-positive bacteria?
Gram Positive: Bacterial walls have one layer of carbohydrate and protein molecules (takes up
crystal violet)
Gram Negative: bacterial cells have two layers of protein and carbohydrate molecules (take up
safranine)
Gram-negative bacteria take up the Safranine dye and turn the color Pink.
Gram-positive bacteria take up the Crystal Violet dye and turn the color Purple.
Obtaining Energy
1. Autotrophs make food from inorganic molecules.
Name and describe how the two types of these bacteria obtain energy:
Biology 11
Name: ______________________
Blk: ________Date:__________
A. Phototrophic Autotrophs: use carbon dioxide as sole carbon source and light as it’s sole
source of energy
Example: cyanobacteria and some photosynthetic eubacteria
B. Chemotrophic Autotrophs: Obtain energy from breaking down inorganic molecules (i.e
hydrogen sulphide, nitrates, sulfur and iron)
Example: nitrosomonas
2. Heterotrophs obtain energy and carbon from an organic source.
Name and describe how the two types of these bacteria obtain energy:
A. Phototrophic Heterotrophs: Photosynthesis for energy and require organics for nutrition
Example: Green or purple bacteria
B. Chemotrophic Heterotrophs: Breaks down organic molecules to obtain energy (most
bacteria and most animals)
Example: Most bacteria and animals
Bacterial Respiration
Respiration is the process that releases energy by using oxygen to break down food molecules.
Fermentation is the process that produces energy without oxygen.
Observe the three test tubes below:
There is a different type of bacteria in each test tube. Determine whether each type of bacteria is
an obligate aerobe, obligate anaerobe or a facultative anaerobe, and then explain how you came to
this conclusion.
Test tube #1: Obligate Aerobe
Explanation: It can be observed that all the bacteria are
clustered around the top of the test tube. This is most likely
because they are trying to position themselves near to the
source of oxygen in the test tube. The bacteria in test tube 1
are dependant on oxygen to survive and are therefore
obligate aerobes.
Test tube #2: Obligate Anaerobe
Explanation: The bacteria in test tube 2 are all clustered
around the bottom of the test tube. They are most likely
trying to position themselves as far away from the source of
oxygen as possible and are therefore obligate anaerobes (can
only survive in the absence of oxygen.
Test tube #3: Facultative Anaerobe
Explanation: The bacteria in test tube 3 are spread throughout the test tube with a few clustered
towards the top of the tube. Because the bacteria are able to survive throughout the test tube (near
and far away from the source of oxygen) they are most likely Facultative Anaerobes because they
can survive with and without the presence of oxygen.
Biology 11
Name: ______________________
Blk: ________Date:__________
Bacterial Growth and Reproduction
Most often, bacteria reproduce by simple cell division called binary fission.
This is a form of asexual reproduction in which two identical daughter cells are formed
Bacteria can exchange genetic information through the process of conjugation.
Two bacterial cells are connected by a long bridge of protein.
The genetic information of the donor cell is then transferred to the other cell called the recipient
cell.
Certain types of bacteria can survive harsh environmental conditions by developing endospores.
Label the diagram of a typical bacterium using the following terms
1.
2.
3.
4.
5.
6.
7.
8.
Cell membrane
Capsule (outer membrane)
Cell wall
Flagella
Genetic material
Ribosome
Pili
Cytoplasm
Now answer the following questions:
1. Is the bacterium in the diagram a bacillus, coccus or spirillium? Explain.
Bacillus, the shape of the bacterium is in the shape of a rod. Coccus would be a sphere, and
spirillium would be in a spiral shape.
2. How would you expect this bacterium to move? By using it’s flagella to propel it’s body.
3. Suppose that this bacterium was a streptobacillus. What kind of colonies would you expect it to
form? The colonies would form in chains.
4. This bacterium is gram-negative. What happens when it is subjected to gram staining?
The bacterium would take up the safranine dye and turn the color pink.
5. The bacterium is facultative anaerobe. What process or processes would you expect it to use to
break down food? Explain.
The bacterium could use either respiration or fermentation to break down food because it is a
facultative anaerobe. In the presence of oxygen the bacterium would use respiration to breakdown
food and release energy. When there is no oxygen available the bacterium would use fermentation
to produce their energy.
Biology 11
Name: ______________________
Blk: ________Date:__________
Helpful Bacteria
Many bacteria are saprophytes. Saprophytes release digestive enzymes into the organic material
around them (e.g. cellulose from trees) and break down the material into nutrient molecules that
the bacteria or other organisms can absorb. This process causes the organic material to decay.
Explain what would happen without the presence of saprophytes:
Decay is a vital link in all nutrient cycles. Without it, the matter from once-living organisms
would accumulate and stop the biosphere from functioning normally. Food chains would be
broken—producers would not have nutrients to grow; and without producers, consumers would
have nothing to eat.
Describe and explain two ways bacteria play a helpful role in our environment (Use the table and
the library/internet to support your answers)
1. Bioremediation: using bacteria to treat polluted sites
Example: A toxic wood preservative called penta-chlorophenol has been known to seep from
storage containers, contaminating nearby soil and underground water. The cost of cleaning the soil
by the traditional means of excavating and burning contaminants ranges from $200 to $300 per
cubic metre. In some cases, hundreds of tonnes of soil must be excavated. A bacterium from the
genus Flavobacterium is a dramatically more economical and efficient alternative to these
traditional methods of detoxification. The toxic compound is actually a nutrient for the bacterium.
The bacteria require only oxygen and nutrients found in the soil. The treatment is also
inexpensive:$30 to $50 per cubic metre of soil. Besides its low cost, another advantage is that
the bacterial population grows as long as the toxic molecules remain; once the chemical has been
broken down, they die.
2. Bacteria as Pro-biotic agents
Researchers are discovering that many lesser-known bacteria, grouped as probiotics (literally,“for
life”), help maintain health and may have the potential to prevent disease. Although they consist
mainly of lactic acid bacteria, bifidobacteria (Y-shaped,found in the human intestine) and yeasts
have also been used successfully. In the future, look for these organisms to be included in foods or
food additives, or used in the treatment of ear, intestinal, and urinary-tract infections; the reduction
of blood cholesterol levels; and the prevention of infections, tooth decay, and perhaps some
cancers.
Biology 11
Name: ______________________
Blk: ________Date:__________
3. Bacteria in Industry
During metabolism, bacteria make enzymes that are useful in many industrial processes. Industrial
fermenters (Figure 2) are used to harvest enzymes, which, in turn, are used to produce consumer
products. Examples are summarized in Table 1. Even though enzymes can be used, they are
costly. Usually, intact bacteria are used because they are less expensive.
Harmful Bacteria
There are hundreds of strains of E.coli bacteria; the combination of numbers and letters in the
name of the bacterium refers to the specific markers found on the bacterium’s surface. Whereas
most live harmlessly in the intestines of healthy animals, E.coli O157:H7 produces a dangerous
poison or toxin. The major source of E.coli O157:H7 infections is undercooked ground beef, since
fecal matter can contaminate beef as the meat is processed. E.coli O157:H7 is found in the
intestines of cattle; when the cattle are killed, the bacteria can become mixed into beef when it is
ground. Other sources of E.coli include processed meats, sprouts and leafy green produce,
unpasteurized milk and juice, and contact with cattle. Drinking inadequately chlorinated water or
swimming in contaminated lakes or pools may also expose people to this deadly strain. The
organism is easily transmitted from person to person. Day-care or long-term-care centers, cattle
barns, and petting zoos are prime areas of concern.
Explain 2 methods for preventing the transmission of E.coli (use the library or internet to research
practical answers)
1. Thoroughly cooking ground beef and meat.
2. Only drink water that has been properly chlorinated (especially when camping etc. )
3. Avoid ingesting water when swimming in contaminated lakes or pools.
4. Don’t eat food when in cattle barns or petting zoos.
5. Properly wash and disinfect food containers and serving utensils (hot water, soaps)