OBJECTIVE SHEET MICROBIOLOGY 1 PROKARYOTES 1. List the characteristics of the Domain Bacteria and the Domain Archaea. 2. Demonstrate aseptic technique when handling bacteria. 3. Classify bacteria based on gram staining, bacteria shape and how the bacteria obtain

and use energy. 4. Define the following: flagellum, pili, bacilli, cocci, spirilla, binary fission, heterotrophs, saprophyte,

chemosynthetic and photosynthetic autotrophs, conjugation, transformation, endospore, toxin, anti-toxin, phagocyte, vaccine.

5. Differentiate between obligate aerobes/anaerobes and facultative

aerobe/anaerobes VIRUSES 6. Discuss the evidence used to classify viruses as living or non-living. 7. Identify the stages of the: lytic and lysogenic cycle. 8. Define the following: bacteriophage, retrovirus, viroids and prions. IMMUNOLOGY 9. Explain how pathogens cause disease. 10. Describe three ways in which a virus can alter the normal functioning of a cell. 11. State two main functions of the immune system. 12. Explain how non-specific and specific defenses occur in the body. 13. Explain how vaccines are made. 14. Describe how scientific knowledge of viral action and DNA structure have been applied in the use of recombinant DNA technology. 15. Describe the relationship between influenza, Asia, ducks, pigs, and humans.

2

Above is an agar plate with bacteria growing on it. Surrounding the colony of bacteria are several different antibiotic discs. The hope is to find which antibiotic produces the largest “killing zone”. Medical labs can then safely prescribe the most appropriate antibiotic to a person with this bacterial infection based on these “sensitivity” tests.

3

Why Study Bacteria? At first sight, it may seem that the conquest of disease is the most important reason for studying bacteria. It is well known that some bacteria can cause disease — although it should be borne in mind that many diseases are caused not by bacteria, but by viruses, fungi or protozoa. Diseases, which are caused by bacteria include, for example, typhoid and syphilis in humans, anthrax, and tuberculosis in both humans and animals, and certain types of wilt and soft rot in plants. Many such diseases have been conquered or controlled largely as a result of studies and experimental work carried out on the causal agents by medical, veterinary and agricultural bacteriologists. Important though they are, the disease-causing bacteria represent only a very small proportion of the bacteria as a whole. Most bacteria do little or no harm, and indeed, many are positively useful to humans. Some, for example, help in our fight against disease by producing a number of important antibiotics. Many bacteria are important because their activities are essential to the re-cycling of matter upon which, ultimately, all life depends. For example, some species of soil bacteria bring about chemical changes, which are essential steps in the nitrogen content of the soil. Since certain forms of nitrogen (nitrate, ammonia) are necessary for plant growth, an understanding of this type of bacterial activity is essential for better management of land and crops — so vital to the survival of our ever-expanding population. Surprisingly, perhaps, bacteria also make significant contribution in our food industry. We usually think of bacteria as a nuisance where food is concerned, causing spoilage and ‘food poisoning’, but particular species of bacteria are actually used in the production of some types of food. For instance, the manufacture of dairy products such as butter, cheese, and yogurt depends on the ability of certain bacteria to convert milk sugar to lactic acid; furthermore, the characteristic flavours of these products often owe much to other compounds produced by the bacteria during the process of manufacture. Bacteria are also employed in the manufacture of certain vitamins (eg. Vitamin B12) and amino acids. This is by no means a complete account of the importance of bacteria in our everyday lives. However, from what has been said it should be clear that the more we can learn about these active but unseen organisms the more effectively we can minimize their harmful effects and exploit their useful abilities.

4

5

Distribution of Bacteria Activity Bacteria are everywhere. Unless you get an infection or grow them on a specially prepared medium such as an agar plate, you might not be aware of them. When grown on an agar plate, they produce colonies. These eventually become large enough to see with the unaided eye. The nature of these colonies can help you to identify certain kinds of bacteria. 1. With a partner, obtain a sterile petri dish with nutrient agar from the back of the room. With the marker supplied, draw 4 lines across the back surface of the dish creating 8 equal quadrants. Label the quadrants A through H.

2. Have your partner fold the ends of a piece of tape to make 7 loops of scotch tape making sure to touch only one side of the outside sticky part of the tape. Carry the loops around on your hand. 3. You and your partner will leave the classroom to find 4 “interesting” places in the school that you would like to obtain a bacteria sample from. Touch the surface of interest with the sticky part of one piece of tape and lightly transfer this to quadrant “B” in the nutrient agar by slightly touching the agar gel. You will not touch quadrant A. Leave quadrant A alone. Start on quadrant B. DO NOT smear, rub, or press too hard as you will destroy the agar medium. Throw your piece of scotch tape away. DO NOT leave it in your agar! Record each location tested. 4. Repeat this process for 3 other quadrants from 3 other interesting locations. You will test the last 3 quadrants by going to any 3 locations that you think are very clean surfaces. Remember to record where each location is from and what quadrant it was placed in.

6

5. When you have completed all 7 quadrants, tape the lid on the dish with a small piece of tape and identify your dish with a symbol or name. Place the dish UPSIDE DOWN in the corner of the bacteria incubator. Failure to do this will destroy your sample. We will culture the bacteria for several days to see if any colonies develop.

6. On a separate sheet of paper, use a ruler to make up a data table to record your results. Include an appropriate title. Using a ruler, make up a data table to record your observations. Include a sketch of your growth pattern seen on the Petri dish.

Include the following Questions: 1. What was the function of section A in your Petri dish? 2. What areas were you somewhat surprised by the results? What could be a possible reason? 3. What does the term pathogen mean? 4. Do you see any possible evidence that organisms other than bacteria are present in you samples? Explain. 5. How many different types of bacteria did you detect? What clues led you to believe that you may have different types? 6. If some of the bacteria on various surfaces happened to be pathogenic (disease-causing), how might their spread be reduced?

7

Microbiological Safety Techniques ASEPTIC TECHNIQUE Individual bacteria are not dangerous. However, when grown in nutrient broth or on agar, they quickly reach numbers that can cause severe health problems. Accordingly, you are expected to treat specimens with extreme care. Here are the steps that will keep us all safe: You want to avoid leaving an invisible trail of bacteria left behind in your work area by paying attention to the following techniques. These are very important when working with unknown bacteria. 1. Do not eat or drink anything in the lab when dealing with cultures. 2. Clear off a work area and put a piece of paper towel down on your desk. 3. Never open a contaminated plate unless directed to do so by the teacher. 4. **Handle the contaminated Petri dish with your non-writing hand only. This allows you to draw diagrams of the results without potentially getting bacteria on your pen or pencil. Again, avoid an invisible trail of bacteria. Only put the plate down on the paper towel.** 5. Wrap your petri dish in paper towel and carefully put contaminated plates into the disposal bag indicated at the back of the room when you have made your observations. 6. When working with contaminated broth, have the contaminated test tube in a beaker at the workstation. Flame the inoculating loop before using. Dip the loop 5 separate times into the broth to make a ‘lawn’ on the Petri dish. Flame the entire loop red hot when done. Report any spills to the teacher. Be careful not to ‘flick’ the loop on the top of the test tube when removing it from the broth. When finished, place the test tube back into the beaker at the front of the room for sterilization. 7. Wash your hands with soap and warm water from the back of the lab as soon as you have finished.

8

9

PROKARYOTES Prokaryotic cells are separated into two different domains: the domain Bacteria and the Domain Archaea. You might recall that Domain Bacteria have prokaryotic cells with thick, rigid cell walls that surround a cell membrane. The cell walls contain a substance known as peptidoglycan. Domain Archaea live in extreme environments such as volcanic hot springs, brine pools, and black organic mud devoid of oxygen. Their cell walls do not contain peptidoglycan and their cell membranes contain unusual lipids never found in any other organism. Label the following diagram of a typical bacteria cell.

What function do the pili and flagella have in the bacteria cell? ____________ _______________________________________________________ _______________________________________________________

10

Identifying Prokaryotes Reference pg. 473 Due to the microscopic size of bacteria, distinguishing one type of prokaryote from another may be difficult. There are several ways that biologists identify one type of bacteria cell from another. These include: __________________________ __________________________

__________________________ __________________________

The diagrams above show three typical shapes that help you identify the type of bacteria present. These include the coccus (spherical), bacillus (pill-shaped), and the spirillum (curly). Streptococcus bacteria are so named because they are spherical in shape. So the name can indicate the shape of a bacteria cell as well. Obtaining Energy Identifying bacteria based on how they obtain energy really demonstrates the great diversity that exists in these two domains. Most bacteria are heterotrophic (meaning that they get their energy from consuming organic molecules made by other organisms), but some are autotrophs (meaning that they make their own organic molecules – usually the photosynthesizers) Identify two kinds of heterotrophs: _______________________________ _______________________________ How are the two types of heterotrophs similar to each other? ______________________________ _______________________________________________________

11

Identify two kinds of autotrophs: _______________________________ _______________________________

How are the two types of autotrophs different from each other?

____________________________________________________________

________________________________________________________

Releasing Energy After obtaining the energy they need to carry on life, bacteria release their energy in ways very similar to us. They use cellular respiration, fermentation, or both. What is important is whether the bacteria can live in oxygen or not. Organisms that must live in the presence of oxygen are called __________________________. The bacterium that causes tuberculosis mycobacterium tuberculosis is an example of this type of bacteria. Organisms that cannot live in the presence of oxygen are called __________________________. Clostridium botulinum is an example of this type of bacteria. Facultative anaerobe bacteria seem to have the advantages of both types of bacteria.

They can live with or without oxygen. When oxygen is present they use

_______________________________ to make ATP. When oxygen is not present, these bacteria can switch to ____________________________ to make their ATP. Facultative anaerobes do not require oxygen, but they are able to take advantage of it if oxygen is present.

12

Gram Stain Activity The Gram stain provides biologists with a means to classify various bacteria types. This procedure was developed by the Danish bacteriologist Christian Gram. The Gram stain is not used to identify Domain Archaea due to their immense diversity and variability in staining, but it is used only for the Domain Bacteria. Some bacteria cell walls stain different than others, so the Gram stain is called a Differential stain. Gram-positive bacteria are stained purple while gram negative bacteria are stained red. You are going to determine whether the bacteria provided are gram positive or negative. You will also classify your bacteria based on their shape under the microscope.

A. Bacterial slide Preparation:

1. Place a drop of distilled water on a clean glass slide. 2. Flame the inoculating loop and the mouth of the culture tube. 3. Remove a small quantity of bacteria from the slant. 4. Flame the mouth of the tube and replace the cap. 5. Mix the bacteria with the water on the slide and spread thinly. 6. Allow the smear on the slide to air-dry. Be patient. 7. Using a clothespin or similar holding device, pass the slide, smear side up,

through a flame three times to fix the bacterial cells. Fixing kills the bacteria and causes them to stick to the slide.

8. Allow the slide to cool. Be patient.

B. Performing the Gram Stain. 9. Once the slide is air-dry, use the clothespin to hold the slide. Go to a sink and

apply 3-4 drops of Crystal Violet Stain on the bacteria and let it sit for 60 seconds.

10. Rinse with tap water gently. 11. Apply 2-3 drops of Gram’s Iodine solution for 60 seconds. 12. Rinse with tap water gently. 13. Decolorize with 95% ethanol. Hold the slide at an angle to allow the ethanol to

drip across the slide until the runoff is almost clear. Apply several drops until this is accomplished.

14. Rinse with tap water gently. 15. Apply 2-3 drops of Safranin stain for 60 seconds. 16. Rinse with tap water gently. 17. Gently shake off any excess water on the slide. Blot the bottom of your slide dry

with paper towel so there no water gets on the microscope stage. 18. Repeat all these steps with a second sample of bacteria provided. 19. Use a clean cover slip and observe your bacteria slides for color and shape under

high power. Adjust your iris diaphragm to maximize detail.

13

20. Diagram your results below and indicate which bacteria are coccus, bacilli, or spirilla. Indicate each bacteria type as either gram + or gram -. Remember Gram positive stain purple and Gram negative stain red.

14

Growth and Reproduction There are three main ways that bacteria reproduce. The most important aspect of reproduction is the relationship of which method is used to the type of environment present. Some environments promote one method of reproduction over the other. Consequently, you would expect to see bacteria that can use a particular reproductive method in that area. ________________________ is a type of asexual reproduction found in bacteria that divide and split into two genetically identical “daughter” cells. What type of environment would you expect to find if all the bacteria cells are genetic clones of each other? _______________________________________________________ Another type of reproduction called ______________________________ actually involves the “transfer” of genetic material from one cell to the next. They do this by forming a small “hollow bridge” from the pili on the cell walls to connect each other. This exchange of genes provides diversity among bacteria cells

What type of environment would you expect to find if all the bacteria cells are involved with conjugation? _______________________________________________________

When environmental conditions become harsh, bacteria may form structures called _____________________. The spore contains a small amount of critical cytoplasm and DNA. Spores can remain inactive or dormant for months or even years waiting patiently for conditions to improve so that the dormant spore can become active and “germinate”.

This is a picture of a spore. The dark mass in the middle is the critical bacterial DNA surrounded by a small amount of the cell’s cytoplasm needed for survival. The rest of the outer structures are tough layers dedicated to protecting and preserving the bacteria cell until a favorable environment occurs. The spore comes from a bacteria cell called bacillus subtillus. It makes a chemical that breaks down starch, similar to the chemical found in your digestive system that does the exact same thing.

15

Controlling Bacterial Growth Activity

Chemical substances that either kill bacteria or inhibit their growth are called antimicrobial agents. There are three types: Antiseptics, which are used on living tissue to inhibit growth or kill bacteria. Disinfectants are chemicals used to inhibit the growth or kill bacteria on nonliving surfaces; and antibiotics, which are chemical substances produced by living organisms, which inhibit the growth of bacteria. The effectiveness of each type of antimicrobial agent is influenced by many factors. Some of these factors include the environmental conditions in which the agent is applied, the chemical properties of the agent, how long the agent has been stored, and the rate of deterioration of the agent. Purpose: To study the effectiveness of common cleaners and antibiotics. Materials: peppercorn bacteria, agar plate, tweezers, clear tape, Q tips, confetti discs, various cleaners, various antibiotics (ex. Bacitracin erythromycin, tetracycline, amoxicillin, streptomycin) Procedure: 1. Using an inoculating needle, gently sterilize the needle under the burner until the needle loop glows red. After several seconds of cooling, contaminate your needle with the bacteria of a peppercorn sample at the back of the room. 2. With your contaminated inoculating needle, make streaking motions across your Petri dish lightly touching the agar. Re-contaminate the needle five times and streak your plate at 90° angles each time. Try not to damage the surface of the agar too much with the needle. Repeat with a second Petri dish.

16

3. Sterilize your inoculating needle again under the burner.

4. On the bottom of the two agar plates, divide the area up into 4 quadrants with a marker and then label the quadrants 1 - 4 as shown. 5. Soak 7 confetti discs in separate antimicrobial agents having some soaked in disinfectants, some in antiseptics and some in antibiotics. Make sure that you remember which disc is soaked in which agent. 6. Use your tweezers to place a soaked disc on quadrant 2,3,4,5,6,7 and 8. Leave quadrant 1 untouched (do you know why?) Record which antimicrobial agent is in which section.

7. Cover your culture and set the sealed, labeled, petri dish in the incubator upside down to grow. Put your initials on your plate somewhere.

8. Your group may be asked to prepare a dish using pond water instead of peppercorn bacteria. Follow steps 1-4 again but use pond water instead. 9. Clean your area and notify your teacher for an inspection before any group members begin the questions or conclusions.

17

With an appropriate title and your group member’s names, hand-in a paper with your results tabled and the answers to the following questions: Questions: 1. Draw a sketch of your two Petri dishes and develop a chart displaying the results of your experiment. Measure the zones of influence. 2. Which substance seemed to be the most effective in each culture? Least effective? 3. Would you use disinfectants to kill bacteria on or in you? Why or why not? 4. If you worked at a hospital lab and you received a sample of bacteria from a sick patient, how would you plan on finding out how to treat the patient best? Explain. 5. If you had a viral infection, which antibiotic would you suggest? Why?

18

VIRUSES Reference pgs. 478-483 Viruses are particles of nucleic acid, protein and sometimes, lipids. They vary in size and structure but all viruses have one important thing in common: _______________________________________________________ _______________________________________________________ _______________________________________________________

Even though viruses differ widely in their structure, they all are made up of a core of either DNA or RNA, which is surrounded by a protein coat, or capsid. Viruses are not thought to be alive. Look at the chart below. What do you think?

19

Viruses can be very tricky. The capsid includes ___________________ that enable the virus to enter a _______________ cell. This occurs when the capsid proteins bind to receptors on the surface of a cell. This “tricks” the cell into letting the virus inside the cell. Once inside, the ____________________ are expressed. Usually the viral genes cause the host cell to make new viruses when the viral DNA takes over the cell’s organelles and instructs it to make viral proteins, and even more viral genes. Viruses are very _____________________ about the type of host cell they infect. This is because of their intimate connection with host cell surface proteins and even the host cell’s DNA. We know that because of “viral specificity” plant viruses cannot infect humans or bird viruses cannot infect other animals such as gorillas. Occasionally, mutations can happen that may make a virus susceptible to another species. Lytic and Lysogenic Infections pg. 480-481

Study the diagram above and reference the color diagram on text page 480

20

A virus called a T4 Bacteriophage is an example of a virus that causes a lytic infection. In a lytic infection, __________________________________________ _______________________________________________________ _______________________________________________________ The Bacteriophage Lambda can cause a lysogenic infection. In a lysogenic infection, _______________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ What is a prophage?_________________________________________ _______________________________________________________ What does a prophage do? _____________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ Retroviruses Any virus that carries RNA instead of DNA is called a retrovirus. When retroviruses infect cells they cause the host cell to “re-write” its own DNA! You remember in mRNA transcription, DNA makes a copy of a gene into mRNA. (DNA --> RNA). Retroviruses are so called because they work backward–that is, from RNA --> DNA. Some cancers are caused by retroviruses. The HIV virus is a retrovirus.

21

Viral infections are quite varied. They disrupt homeostasis in the body. They can destroy certain cells or change how they function. Antibiotics do not work against viruses. There has been some recent success with anti-viral medications if they are taken early enough. The best way to protect against most viral infections lies in prevention. Most vaccines provide protection if they are used before an infection begins.

Viroids and Prions There are two other disease-causing particles, viroids and prions. Explain the difference between viroids and prions: ____________________ _______________________________________________________ _______________________________________________________ How are prions different from viruses? ____________________________ _______________________________________________________ _______________________________________________________ Name a disease that occurs in humans from prions ____________________ ___________________________________.

22

23

24

25

Cell Wars (video) 1. How is the influenza vaccine made? _______________________________________________________ _______________________________________________________ 2. What effect does the vaccine have on your body? _______________________________________________________ _______________________________________________________ 3. What is the first part of your immune system to attack a foreign antigen? How does it recognize a substance as being foreign? _______________________________________________________ _______________________________________________________ 4. If people around you have been vaccinated against a specific pathogen, why do you also need to be vaccinated? _______________________________________________________ _______________________________________________________ 5. Influenza viruses usually carry Asian names and involve pigs, ducks and human in a complicated inter-relationship. Describe the mechanism by which the flu virus keeps changing. _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________

26

The Body Against Disease #1 1. Name two types of diseases. ________________ ________________ 2. Name a disease caused by each pathogen type. _______________________ _______________________ 3. How do pathogens enter the body to transmit disease? _____________________________________________________ _____________________________________________________ 4. List ways to prevent the spread of disease. _____________________________________________________ _____________________________________________________ 5. Non specific defenses of your body try to prevent pathogens from entering the

body in the first place. What are some of the body’s initial defenses against disease?

_____________________________________________________ _____________________________________________________

_____________________________________________________ _____________________________________________________ 6. List the steps involved in “fighting” bacteria as they enter the body. _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________

27

The Body Against Disease #2 The Immune Response 1. What is combined immunodeficiency disease. _____________________________________________________ _____________________________________________________ 2. What two system make up the immune system? ______________________________________________________ 3. The immune system works by distinguishing between ‘self and non-self’. The immune system must accept and protect the body’s own cells and reject and destroy foreign cells. Each cell has on its membrane a ‘marker’ called an antigen – a sort of cellular ID marker indicating what the cell contains. An antigen’s basic feature is its shape. The circulating lymphocytes ‘read’ each cell’s antigen, and when they read an antigen as being foreign, they initiate the immune response. 4. How does the immune system react to foreign cells? _____________________________________________________ _____________________________________________________ 5. Antibodies destroy foreign cells by producing a specific antibody that acts like a ‘smart-bomb’ to fit the foreign antigen. The antibodies agglutinate (or clump) the foreign cells together so they can’t circulate. Antibodies can also activate a substance called ‘complement’ which is a blood protein that can explode foreign cells or physically coat pathogens to prevent them from doing harm to the body’s own cells. 6. What is natural immunity? What is the risk in developing natural immunity? _____________________________________________________ _____________________________________________________

28

7. What is the benefit of immunization? How does it work? _____________________________________________________ _____________________________________________________ _____________________________________________________ _____________________________________________________ 8. Why does immunization continue to be important even though no cases of a particular disease may have been reported in years? _____________________________________________________ _____________________________________________________ 9. Antibiotics are very successful in treating some illnesses. However they are limited in their usefulness. Only diseases caused by bacteria can be treated with

antibiotics. Also, pathogens can develop strains that are resistant to these drugs. Gonococcus bacteria have adapted to penicillin, becoming resistant to the antibiotic. New, more powerful drugs must be developed in order to combat these resistant strains. Overuse of antibiotics has given rise to rapid growth of resistant strains. We are already finding bacteria strains resistant to every known type of antibiotic.

29

MICROBIOLOGY 2 PROTISTS (DOMAIN EUKARYA) 1. Identify 8 life activities common to all living organisms. Include an understanding

of Locomotion, ingestion digestion, secretion, egestion, respiration, excretion, and reproduction.

2. List the characteristics common to Protists. 3. Observe and identify the structures present in a Paramecium that allow it to perform life activities. 4. Observe and identify the structures present in a Euglena that allow it to perform life activities. 5. Identify the different methods of locomotion used by Protists. 6. Describe the role of plankton. 7. Explain the life cycle of Malaria.

30

31

LIFE ACTIVITIES To keep alive and healthy, all organisms from the simplest to the most complex must carry on certain life activities. Because these activities center about the utilization of energy, they very often result in different organisms using a variety of different ways to perform these life activities. Here is an introduction to the variety of Life activities performed by all organisms we will study.

1. LOCOMOTION Sometimes called motility, this allows most organisms to rove about in search of food or to avoid becoming food. Sessile, or fixed, organisms, which cannot move about but live firmly attached to the substratum, have moving parts that propel food their way. These include sponges, corals, barnacles, certain bivalves, and others. In addition, there are sedentary organisms like clams or web-building spiders, which feed while remaining for some time in one spot but which can and do move about to escape danger or to take up new and more profitable feeding stations. 2. INGESTION This is the taking in of food. Organisms differ strikingly in their mode of ingestion. The differences are related

partly to the diversity of the food itself. Mouth parts that tear flesh will not do for chewing wood; sucking sap is not the same as sucking blood. In its essentials, the feeding machinery involves: a set of sensory receptors to get information about the external environment, mechanisms for locomotion and ingestion, and a means to obtain the food while avoiding becoming food itself. 3. DIGESTION This is the chemical alteration of food into a useable source of energy for maintenance energy and growth and reproduction. Ingested foodstuffs must be broken down into simpler nutrient molecules that may be delivered to various parts of the body. To help this breakdown, the living organism has a digestive apparatus into which are poured a number of kinds of chemical substances or secretions. 4. SECRETION This is the manufacture of special chemical substances out of materials obtained from the surrounding environment. These substances, or secretions, may be used where produced or may be carried to other parts of the organism. Silk, sponge fibres, calcareous shells, and mucus are well-known animal secretions. Less easily seen, but more essential are the secretions which are involved with the chemistry of life. These include enzymes which play a major role in speeding up everyday chemical reactions that would normally take place so slowly that they would be of no use to the organism. 5. EGESTION Sometimes called elimination. This is the ejection from the body of indigestible food or other accumulated solid wastes. Most plant-eaters do not have the enzymes needed to digest completely the woody tissues of the plants they feed upon. Most insect-feeders cannot break down the complex substances that form the hard outer skeletons of insects. These indigestible portions of the food constitute the solid waste, or feces, and must be removed. 6. RESPIRATION Is a destructive chemical process by which food is burned in the release of energy. The energy stored in the food through the photosynthetic action of green plants is released in somewhat the same way that man releases, by burning, the energy stored in coal. Because animals cannot break down food using great sources of heat, we require enzymes (chemicals) that break down food at body temperatures with little energy required. All living organisms produce ATP as their energy currency molecule. The energy of ATP is found in the chemical bonds of this molecule. 7. EXCRETION This is the separation from the living cell of liquid waste containing nitrogen. Nitrogen is toxic to cells and must be removed through excretion. When an organism breaks down (burns) proteins, carbohydrates and fats,

carbon dioxide, water and nitrogen compounds are produced. In humans, the kidney remove the nitrogen which is temporarily stored as urea. 8. REPRODUCTION This is the production of new individuals to take the places of the old ones which die because their machinery wears out or because they are eaten or destroyed by their enemies. There are numerous methods of reproduction performed by a myriad of organisms that will be explored in class.

32

PROTISTS text reference pg. 496-498 Protists are so diverse that many biologists don’t agree on how to classify protists. Currently, they are in the Domain Eukarya because they consist of Eukaryotic cells. Most are unicellular and some are multicellular but the cells are all identical to each other and don’t have separate functions like the cells we see in most multicellular organisms. We will take the traditional way of classifying Protists by putting them into the Kingdom Protista. Evolution of Protists Where did the first protists come from? How could simple prokaryotic cells evolve into complex eukaryotic cells with organelles? Biologist _____________________ has hypothesized that the appearance of the

first eukaryotic cells most likely would have evolved from a __________________

among several prokaryotes.

THE ENDOSYMBIONT HYPOTHESIS

33

Protists are sometimes classified by their means of obtaining nutrients. For this reason, there are animal-like, plant-like and fungus-like protists.

Plasmodium Plasmodium causes malaria. Humans can get malaria from vectors. A vector is an organism that can transmit a disease. In this case, it is the Anopheles mosquito. Mosquitoes do not cause malaria, a protist found inside them called Plasmodium causes malaria.

34

35

PARAMECIUM A Complex Protozoan

Paramecium are found everywhere in fresh waters and can be obtained in enormous numbers by letting a bit of food decay in pond water. Like an ameba, a paramecium consists of a microscopic mass of protoplasm which is differentiated into a semi fluid granular interior and a denser, clear, outer layer. A paramecium is covered by a stiff but flexible outer covering called a pellicle. This covering gives the protist a definite shape, somewhat like that of a sole of a slipper. Also, a paramecium has distinct front and rear ends, or anterior and posterior ends. The anterior is rounded, the posterior pointed – a good example of streamline form. Beneath the outer covering, and imbedded in the clear outer cytoplasm, are small oval bodies called trychocysts. These bodies reach the surface through pores and can be discharged to the exterior environment. When discharged, they become long fine threads. It is thought that they provide the Paramecium with some protection since it is discharged when touched by chemicals or when attacked by an enemy. Trychocysts can also anchor the protist while feeding on bacteria.

LOCOMOTION The paramecium has put on speed by developing accessory structures for locomotion which are not unlike oars in a boat. This small protist is covered with about 2500 small hairs which are really small protoplasmic extensions through small holes in the pellicle. These hairs are called cilia, and they beat in a wave-like form to provide a relaxed forward part of the stroke and then a strong backward lash. The combined effect of all the cilia rhythmically stroking backward, is to drive the protist forward. Because of their orientation and oblique beating of the cilia, the protist will revolve on its long axis so that as it swims through the water, it revolves continually and swims a spiral path. A paramecium can swim backward by a reversal of the ciliary stroke and can turn in any direction.

INGESTION, DIGESTION, EGESTION The food catching apparatus of the paramecium is much more specialized than most protists. Food is taken in only at a definite place on the surface. One side of the paramecium is strongly depressed or indented, called the oral groove, as if a piece had been cut out of the protist. This groove leads backward to an opening, the mouth pore, from which a funnel-like tube, the gullet, extends down into the cytoplasm. When a paramecium stations itself near a bit of decaying material, the beat of the cilia in the oral groove drives bacteria and other minute organisms toward the gullet. The bacteria are concentrated into a ball at the bottom of the gullet. The finished ball then passes as a food vacuole into the cytoplasm. A paramecium that has found a suitable bit of debris and is feeding actively will soon become filled with food vacuoles. These vacuoles are moved about in the cytoplasm by a process called cyclosis. The contents of the food vacuoles undergo digestion as digestive enzymes from the cytoplasm enter the food vacuole and chemically break apart the bacteria and food particles. The few indigestible remnants in the food vacuoles are finally eliminated from the protist through a structure called the anal pore. EXCRETION Oxygen and carbon dioxide are exchanged by diffusion. Oxygen is taken in and used for the ‘burning’ of foods and carbon dioxide, water, and nitrogenous wastes (like ammonia and urea) are given off. Two contractile vacuoles occupy fixed positions near the surface on the side opposite the oral groove, one near the anterior end, the other near the posterior end. Each vacuole is surrounded by a circle of canals that radiate from the vacuole for some distance into the cytoplasm. At short intervals these canals fill with fluid, then discharge their contents to form the vacuole, which in turn ejects the fluid to the exterior. Contractile vacuoles play a major role in controlling the water balance of the paramecium.

36

In a typical paramecium, the two contractile vacuoles can eliminate a volume of water equivalent to its body volume in about ½ and hour. An average man eliminates a volume of urine equal to his body volume in about three weeks, but he also excretes water through the lungs and sweat glands. ASEXUAL REPRODUCTION The innermost cytoplasm contains a lot of fluid, food vacuoles, fat droplets, and other food bodies as well as two nuclei, one large and one small. The large nucleus or macronucleus appears to be concerned with the ordinary business of the cell, while the small nucleus or micronucleus is especially active during reproduction. A paramecium reproduces asexually by dividing in two. This process is called binary fission. Both kinds of nuclei elongate and pull apart into two halves, one of which remains in each daughter cell. A constriction forms around each cell, deepens and eventually splits the paramecium into two new daughter cells. Each half forms the parts necessary for a complete paramecium. When well fed, paramecia may divide two or three times daily, so that enormous numbers of them can be obtained in a short time. SEXUAL REPRODUCTION The beginnings of sexual processes occur in the paramecium, although they do not show visible differentiation into males and females. This process is called conjugation. Two individuals unite by their oral grooves, their nuclei undergo complicated changes, the result of which is the passage of a portion of the micronucleus from each paramecium to the other. Each migrating nucleus fuses with the opposite remaining nucleus. The two paramecia separate and undergo a series of divisions; the resulting paramecia continue with their usual activities. Although the more typical sexual reproduction involves sperm and egg (which is not seen in conjugation) the essential features of the sexual process found in higher animals, (that is, the transfer of genes from one individual to another) is present.

37

BEHAVIOR The behavior of a paramecium is exactly what one would expect of a protist that has no specialized sense organs to direct its movements. When not feeding on bacteria, it roams about ceaselessly, bumping ‘head-on’ into obstacles in its path. After such a collision, the paramecium backs up by reversing the beat of its cilia, turns to one side, and goes off in a new direction. If the second path results in a collision the whole process is repeated until the protist finds a free path to continue its course. This set of movements is typically called the avoidance reaction. Mechanical obstacles, excessive heat or cold, irritating chemicals, unsuitable food, predators, or even light intensity.

In its constant explorations, the paramecium may swim by chance into a region rich in bacteria. Each time that it crosses the boundary of this region into a less favorable area, it gives the avoidance reaction; thus it remains in the more favorable region. A paramecium doesn’t need to enter an unfavorable region before it can react negatively. This would obviously cause an untimely death before it had a chance to react. To solve this problem, the cilia beating constantly in the oral groove draws a constant stream of water, in the form of a cone, toward the oral groove. If there is an irritating chemical in the water ahead or if the water is hotter or colder, a portion of that water will be drawn backward into the oral groove. Thus the paramecium constantly receives ‘advance information’ of the environment ahead and responds with the avoidance reaction without actually having entered the unfavorable region. Paramecia have only a poorly developed ability to discriminate between foods, since they very readily take in and form food balls of almost any minute particles, such as carbon grains, dyes, etc. However, after a time they will reject these inert particles while still accepting bacteria. Paramecia avoid strong acids; but they give the avoidance reaction when passing from dilute acids to ordinary water, and therefore tend to congregate in regions of low acidity. This behavior aids the protist in feeding, because bacteria are most likely to be present near decaying organic matter, which renders the surrounding water slightly acid.

On the whole, it may be said that the behavior of a paramecium is remarkably adaptive for a single celled organism that has to find its way about simply by keeping out of trouble.

38

39

STUDYING PARAMECIA reference pgs. 499-505

Procedure:

1. Make a wet mount slide of the paramecium. Before putting on the cover slip, add one (small) drop of yeast that has been treated with the indicator Congo red. This indicator will turn blue if an acid is present. (such as in digestion)

2. Examine your slide on 40x to ensure that you captured a paramecium. If not, repeat the process until you do. Try to follow a paramecium on 100x noting what is occurring inside it. When one paramecium stops, switch to 400x. Carefully observe the paramecium and answer the questions asked in your lab write-up. The paramecium video on the screen will help you see detail. Take your time, in order to “observe behavior” you have to be patient… discovery takes time.

3. Get two prepared slides – one of binary fission and the other of conjugation. Use these slides to answer Part C. You must scan each slide until you find that type of reproduction actually occurring.

Part A: Life Activities 1. Identify the structures used by a paramecium to move.

_______________________________________________________

2. What are the structures involved with ingestion?

_______________________________________________________ 3. Those structures that help with digestion include?

_______________________________________________________ 4. Egestion or elimination is done by the ________________________ 5. The paramecium is __________ tonic to pond water.

6. To stop from exploding, it has two ___________________________ to get rid of excess water. 7. They contract about ____ times per minute. (observe or watch video)

8. If pure water was injected into the paramecium, the rate of contraction of

these structures would _______________________.

40

9. Oxygen and carbon dioxide pass through the ____________________

by the process of ______________________.

10. Excretion of urea is also done by this process. The process of cellular

respiration is carried out by the _____________________________. Part B. Ingestion and Digestion 11. The paramecium moves with the oral groove facing (forwards/backwards)

12. The yeast is enclosed in food vacuoles produced at the end of the _____________________. 13. As the food vacuoles move around, ___________________ attach and

dump in _______________________________ as evidenced by the food vacuoles turning blue.

Part C. Reproduction 14. Diagram an individual undergoing binary fission.

15. This is an example of _______________________ reproduction. 16. Observe the conjugation slide. How can you tell that this activity is not binary fission? _________________________________________ 17. What is happening between the individuals? _____________________ ____________________________________________________ 18. If the paramecium are in a stable environment that is not changing, the type

of reproduction that would be best would be _____________________

41

Label the diagram of the Paramecium below:

What process is going on in this picture?

What advantage does this process give Paramecium in changing environmental conditions? _______________________________________________________ _______________________________________________________

42

Review the process of conjugation in the diagram below:

Note: Even though the paramecium are genetically identical to each other, they are genetically different from the paramecium that started the process. This little difference in genetic make-up may be enough to give the paramecium an advantage in an ever-changing environment.

43

STUDYING EUGLENA reference pgs. 506-509

Procedure: Make a wet mount slide of the Euglena. Find them first under low power, then medium power. When one slows down, switch to high power. Adjust your microscope to maximize light contrast and detail. Label the diagram of the Euglena using the chart at the back of the room page 507 of your text. Feel free to use the internet at home to help. 1. Describe how the Euglena moves. ______________________________

2. Observe the prepared slide at the front desk under high power to identify structures. 3. Would you classify the Euglena as a plant, animal, or combination? Give a reason for your choice. _______________________________________________________ _______________________________________________________ 4. Name two substances that the Euglena is producing. ________________________ ________________________

44

CHAPTER 20 PROTISTA

1. Explain how Protists are different and unique from other organisms. 2. What is a protozoan? Identify four different phylums of protozoans and briefly

describe how each moves.

3. Examine the Malaria lifecycle and answer the following: a) What causes malaria? b) How does malaria hide from our immune system? c) How is it spread? d) How can it be controlled?

4. Termites need a special enzyme that allows them to digest the wood they eat.

Unfortunately termites do not make this enzyme. How is it that they can continue to munch away at wood?

5. What is Giardia and Entanmoeba ? 6. Sometimes when walking along a beach at the water’s edge, your footsteps light

up. At other times the water glows with light. What causes these phenomena?

7. What is the ecological role that phytoplankton play on Earth.

8. What is an algal bloom and how can they disrupt the equilibrium of an aquatic ecosystem?

9. Often there are signs along the east coast warning of “red tide”. What organisms

cause this and how does it hurt humans?

45

TEST TUBE EARTH

David Suzuki …

Imagine a test tube filled with food. That’s the Earth, he says. Now introduce a single

bacterium to that test tube and let it grow exponentially. In the first minute, one

bacterium becomes two bacteria. In the second minute, two become four. Four become

eight. Eight become sixteen. If it takes one hour for the bacteria to multiply until they fill

the entire test tube and there’s no more food — and the bacteria all die — when will the

test tube be exactly half full of food and half full of bacteria?

In the 59th minute.

Which is strange because at that moment things look fine. But the very next minute,

catastrophe strikes.

“Every scientist I talk to agrees with me,” Suzuki declares, “that we’re already past the

59th minute.” We must drastically change the way we live, immediately, before it is too

late.

Small Friends In our daily struggle to live a healthy life, we tend to view all micro-organisms as harmful. Microorganisms are the cause of many human and plant diseases. That is a fact. However, many of the microorganisms we rightly view with alarm have relatives that make important contributions to human and plant life. You know that plants need to take in vital minerals and other inorganic compounds from the soil. These compounds are so important that farmers often spend millions of dollars to add them, in the form of fertilizers, to their soil. However, some plants carry their own “fertilizer factories” right on their roots. The factories are hard-working bacteria. The bacteria, many from the genus Rhizobium, are able to take nitrogen from the air and convert it into the nitrate form that plants can use to make plant proteins.

In this way, the bacteria fertilize the plants on which they live. Bacteria that live in the nodules on the root of this pea plant are able to change atmospheric nitrogen into useable nitrates for the plant. Farmers have found that these bacteria commonly grow on legumes such as peas and beans. Unlike most crop plants, which deplete, or use up, the minerals in the soil, legumes actually improve the soil in which they grow.

47

MICROBIOLOGY VIRUSES, BACTERIA, PROTISTS

48

ACROSS 2. You catch a disease and become immune to it in the future is a type of ________. 8. Spiral shaped bacteria 11. Used to carry out intracellular digestion. 16. AIDS – AID stands for _______________ 18. Produced by some bacteria – causes food poisoning 21. Syphyllis, herpes, warts 22. Symptoms include discharge and pain upon urination. 23. When a virus remains inactive in a cell it is said to be ________________ 24. When injected, causes the body to make antibodies 25. The source of new “spikes” on the influenza virus. 26. An organism that cannot live with oxygen. DOWN 1. Involves a virus taking over a cell and causing it to make more viruses. 3. What happens when a bacteria picks up DNA from the environment 4. Means “against life”. 5. Disease causing organism. 6. Made of only a protein coat and nucleic acid 7. Product of fermentation 9. Virus damaged cells release _____________ 10. Part of your immune system, consists of nodes, and veins. 12. Food vacuoles in the paramecium are formed at the end of the _________. 13. Blue stained bacteria are called _________ 14. Chemosynthetic bacteria are classed as an __ 15. The technique used to put human genes into animals. 16. Found in the blood when we have the HIV virus. 17. Most common type of reproduction in bacteria. 19. Food first enters here in a paramecium 20. Cells that engulf invaders.