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Bacteria and Viruses

1)  List characteristics of monerans and indicate what organisms are found in this group.

2)  Explain the terms prokaryotic and eukaryotic.  Make a list to compare these two kinds of cells.

3)  Identify the 3 major groups of bacteria and describe the structure of a bacterial cell.

4)  Explain the terms: facultative anaerobe, obligate anaerobe, heterotrophic bacteria, saprobe, parasite, autotrophic bacteria, photosynthetic bacteria and chemosynthetic bacteria.

5)  Explain bacterial reproduction in terms of: fission, spore formation, sexual reproduction, conjugation, transformation and transduction.

6)  Describe the role of bacteria in human diseases.

7)  Explain the role of bacteria in decay, nitrogen fixation, and commercial applications.

8)  Explain defenses against disease under the following headings: general defenses and immunity.

9)  Describe the mechanism of immunity in terms of: lymphocytes and lymphatic system, immune response, antigens, antibodies, inborn immunity, acquired immunity, active immunity, passive immunity, maternal immunity and autoimmune disease.

10)  What are antibiotics and antibiotic resistance.

11)  What are viruses.

12)  Describe the characteristics of viruses with respect to size, shape, and composition.

13)  Descrobe how a virus infects a cell and reproduces.

14)  Describe bacteriophages and the role of viruses in human disease.

Answers

1)  Monerans lack a distinct, membrane-bounded nucleus and other organelles that are normally bounded by a membrane.  The members of the monerans are only blue-green algae and bacteria.
(page 514-515)

2)  Prokaryotic cells are cells that have no distinct, membrane-bounded nucleus.  Monerans are prokaryotic cells.

    Eukaryotic cells are cells that to have a distinct, membrane-bounded nuclues.
(See table 30-1 page 515)

3)  The three major groups of bacteria are:

    Coccus which is spherical.  Bacillus which is a rod-shaped.  Spirillum which is a spiral or coiled bacterium.  (see fig 30-2 page 517)

4)

5)

6)  Bacteria can cause disease in humans and other animals.  This is thought to happen by (1) The bacteria becomes so numerous that they interfere with the normal functioning of the body.  (2) In some diseases, bacteria destroy body cells and tissues.  (3) Some bacteria produce toxins, or poisons, that interfere with the normal functioning of the body.
(page 519)

7)  Any organic product can be broken down or decayed by some variety of bacteria.  This means that dead animals can too be broken down.  This returns oxygen, carbon, and nitrogen back to the air and soil.  These elements are necessary for life.
    Also some bacteria produce antibiotics that fight other bacteria.
(page 519-520)

8)  General defences are defences such as skin so bacteria can't enter, stomach acid kills some bacteria, and phagocytes engulf some bacteria.
        Immunity is the ability to resist a disease.  If a disease enters the body the lymphocytes (white blood cells) attack it.  If the disease is weak enough for the lymphocytes to kill it, they will and a memory cell will remember the genetic code of the disease in case the disease ever enters again.  If it does enter again, the memory cells go to the lymph nodes and lymphocytes are created specifically for the destruction of that particular disease.  This is how a vaccination works.

9)  Lymphocytes attack and remember the genetic code for a particular disease.

    Lymphatic system produces lymphocytes that are specifically created to destroy a particular disease.

    Inborn Immunity is an immunity that one is born with.  It is present in all humans at birth.  An example is feline leukemia.  Humans are immune to this disease.  As the name suggests, cats are not immune to this disease.

    Acquired immunity involves antibodies and can be either active immunity or passive immunity.

    Active immunity is when the antibodies are made by the body itself.  This is the immunity one has when one receives a vaccination.  Active immunity develops slowly but the antibodies are present for a long time.

    Passive immunity are when antibodies are obtained from the blood of another person or animal.  Passive immunity is like a quick burst.  It acts quickly, but lasts for a short period of time.

    Maternal immunity is the immunity a child receives from their mother.  This is received from blood and milk.

    Autoimmune disease is a disease where the tolerance of a person's immune system breaks down and antibodies develop against the body's own antigens.  This kills the body's resistance to disease.
(page 166-171)

10)  Antibiotics are chemicals that kill bacteria.  Antibiotic resistance is the term given when a certain kind of bacteria becomes immune to an antibiotic.  This is thought to be like the immunity that a human gets after a vaccination.
(page 498)

11)  A virus is an unclassified organism.  Viruses infect bacteria cells.  They take them over and create more viruses.  Viruses are made up of a nucleic acid core surrounded by a protein coat.  (see fig 30-15) (page528)

12)  A virus ranges in size from 0.01 to 0.3 micrometres.  They attach to bacteria cells with their base and inject their DNA into it.
(page 528)

13)  A virus attaches itself to a bacteria cell and injects its DNA or RNA into the bacteria cell.  This virus DNA overrides the original bacteria DNA and more viruses are produced as a result.

14)  A bacteriophage is a virus that infects bacteria.  In humans this can cause such diseases as the common cold, polio, chicken pox, measles, and influenza.