ACCELERATED BIOLOGY                                                                          ROOM COPY

                     WORKSHEET 5-2 : MICROORGANISMS

1. Stanley discovered the viruses in 1935. These were the last of the major groups of microorganisms        to be discovered.
     A: Why did it take so long for scientists to discover the viruses?
     B: What did Stanley do that allowed him to discover the viruses?

2. One major area of disagreement among scientists today is whether viruses are living organisms or        nonliving entities.
     A: List two characteristics that make some scientists thing viruses are nonliving entities.
     B: List two characteristics that make some scientists thing viruses are living organisms.

3. Two characteristics unique to viruses are their size and their lifestyle.
     A: What range of sizes are most viruses?
     B: In your own words, what does "obligate intracellular parasite" mean?

4. One of the most common forms of viruses is the bacteriophage. The structure of a bacteriophage is        unique in several ways.
     A: The protein coat that makes up the head of the virus has a definite crystal like shape called a             ………………….. which has 20 facets (or faces).
     B: The protein sheath that makes up much of the tail of the virus can ……………… to inject nucleic             acids through the …………… of the virus.
     C: The end plate located at the tip of the tail of the virus has a specific shape that will match up to             the …………………… of the host.

5.  A: Viruses are classified into 4 groups. List these 4 groups.
     B: Viruses tend to feed mainly on 3 types of hosts. Name these 3 common hosts.
     C: Viruses reproduce using two different life cycles, lytic and lysgenic. Label each of the following             statements as belonging to the lytic or to the lysogenic cycle.
            1: viral DNA instructs host DNA to make new viruses immediately after invasion
            2: viral DNA is incorporated into host DNA, forming a prophage
            3: host cell dies quickly after invasion
            4: host cell lives for weeks, months, or years after invasion

6. Louis Pasteur discovered bacteria when he saw "rod-shaped bodies" in ……………………….. .

7. When naming bacteria scientists use a system of prefixes that tell the bacteria's shape and        arrangement. What do the following prefixes, when used with bacteria, mean?
     A: staphylococcus                     B: diplospirillum                     C: streptobacillus

8. Bacteria have several unique internal structures. What is a possible function for each of the following        unique structures found in bacteria.
     A: a sticky outer glycocalyx                     B: a thick capsule

9. Bacteria are classified into groups based on their shape and/or their lifestyle. Which of the groups of        bacteria are being described by each statement below?
     A: members are free-living                         B: are mostly nonmotile, intercellular parasites
     C: are spiral-shaped & cause disease         D: form branched filaments & cause disease

10. When a bacteria wants to reproduce it most often simply splits uses a form of asexual
       reproduction called binary fission. Still bacteria do occasionally chose to reproduce using a form of        sexual reproduction called conjugation.
     A: Why do bacteria prefer to use binary fission more often when they reproduce?
     B: Why would a bacteria ever want to use conjugation?

11. Why are Protozoa often referred to as "animal-like" microorganisms?

12. Protozoa are classified into groups based on how they move. Which group of Protozoa is being        described by each statement below?
     A: moves using flagella                           B: is immobile // simply floats along
     C: moves using cilia                               D: moves using cytoplasmic streaming

13. Protozoa utilize a variety of life styles and habitats.
     A: Name a parasitic protozoa.           Describe where it lives in its host.
     B: Name a free-living protozoa.           Describe where it lives.

14. Fungi are a unique life form. There are paradoxes to their structure and behavior. Try to explain
       the following seeming paradoxes common to all fungi.
     A: They are heterotrophs, but cannot move.
     B: They produce digestive juices, but have no mouth or stomach.
     C: They are composed of many cells, but are not classified as a multicellular living thing.

15. Fungi are classified into groups based on how they reproduce (form their spores). Which group of        Fungi is being described by each statement below?
     A: spores in a club-shaped basidia                               B: spores in a sporangia
     C: have no sexual reproduction                                    D: spores in a sax-like ascus
     E: we can eat their reproductive structure                      F: we use them for brewing & baking
     G: they can grow on our skin                                       H: like to grow on bread

16. Why are Algae often referred to as "plant-like" microorganisms?

17. Algae utilize a variety of life styles and habitats.
     A: Are most algae parasitic or free-living? Where do most live?
     B: What makes a Lichen's life style unique?
     C: What makes Euglena's life style unique?

18. Algae are classified by their colors. Which color is associated with each of the following groups
       of algae?
     A: Chlorophyta                                          B: Phaeophyta
     C: Pyrrophyta                                           D: Chrysophyta
     E: Rhodophyta

19. Which division of algae are being described by each statement below.
     A: cause of the "red tide"                                       B: found at "great depths"
     C: do the bulk of photosynthesis on earth                D: believed to be the ancestors of plants

CRITICAL THINKING: (Omit any 3 of the following Critical Thinking questions)

20. A: Why did thousands of native Indians die after coming in contact with the early pioneers? (It             wasn't due to fighting.)
     B: Why don't today's Indians have the same problem?

21. The human body is designed to keep the minimal number of white blood cells available in the body        at one time due to the large amount of energy required to build and maintain them. One        significance of this is that microorganisms such as viruses and bacteria do occasionally        successfully invade the body and create disease.
     A: Why would the human body evolve a defense that allows us to occasionally get sick, when it             could have evolved a stronger defense?
     B: Since we do occasionally get sick, how does the body react once a viral or bacterial invasion
            has been detected by the body?

22. Lambda, a virus that attacks E. coli, may form a prophage and enter the lysogenic life cycle        immediately after invading the bacteria. Once it enters the lysogenic life cycle, the Lambda        already inside the bacteria inhibits the entry of other viruses into that same bacteria. What is
       the evolutionary advantage of this behavior?

23. We are surrounded by billions of viruses each day of our lives, but we are protected by our skin.        Why don't viruses invade and kill the outermost layer of skin cells?

24. Most bacteria are not disease-causing varieties, but rather help us in many ways. Look up the        following terms, and explain what useful roles are being accomplished by the bacteria that        complete each?
     A: saprophytic                                B: nitrogen-fixing                            C: decomposing

25. Our bodies contain cells that resemble each of the following groups of Protozoa. List a human
        body cell that resembles each of the following. Then EXPLAIN why you chose the cell you did.
     A: Sarcodina                                  B: Ciliophora                                  C: Zoomastigina

26. Disease causing parasites can live in a variety of locations in our body, such as the digestive tract,        our skin, our muscles, our organs, our blood, etc. Why do most parasitic protozoans choose to        live in our blood rather than anywhere else in our body?

27. White blood cells travel throughout our body chasing and eating any disease-causing        microorganisms they encounter. Why do our white blood cells often have more difficulty
        controlling diseases caused by protozoans than by bacteria?

28. Yeast are a type of fungi with only one cell. Why then are they not classified with the:
     A: algae                               B: protozoa                                C: plants

29. Most higher animals such as man secrete their digestive juices into an organ called a stomach        located inside their body. Do fungi secrete their digestive juices and digest their food inside or        outside their body? EXPLAIN.

30. Often there is an advantage for an organism to live in a particular habitat. A frog must live near
        water so that it can lay its shell-less egg in the water during reproduction. Why is it an
        advantage for most algae to live in water if they:
     A: are photosynthetic                    B: reproduce sexually                    C: have thin cell walls
     D: lack vascular tissue for transporting materials around their body

31. Imagine a small pond with a large population of algae and a growing population of fish, frogs,        crayfish, and other animals. The water in this small ponds is often depleted of oxygen during        certain periods in a 24-hour daily cycle, while at other periods the water is saturated with oxygen.
     A: What is the probable cause of this fluctuation?
     B: When would you expect the CO 2 concentration to be greatest in such ponds?           EXPLAIN.
     C: What effect would these fluctuations have on animals living in these ponds?           EXPLAIN.