Download OBJECTIVE SHEET MICROBIOLOGY 1 PROKARYOTES 1. List the

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.
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.
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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.
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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.
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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?
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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.
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PROKARYOTES
Read 471 – 477 in text.
Prokaryotic cells are separated into two different domains:
the Domain Archaea.
the domain Bacteria and
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? ____________
_______________________________________________________
_______________________________________________________
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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? ______________________________
_______________________________________________________
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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.
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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.
2.
3.
4.
5.
6.
7.
Place a drop of distilled water on a clean glass slide.
Flame the inoculating loop and the mouth of the culture tube.
Remove a small quantity of bacteria from the slant.
Flame the mouth of the tube and replace the cap.
Mix the bacteria with the water on the slide and spread thinly.
Allow the smear on the slide to air-dry. Be patient.
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.
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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.
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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.
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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.
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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.
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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?
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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?
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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
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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.
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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 ____________________
___________________________________.
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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.
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
_______________________________________________________
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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.
_____________________________________________________
_____________________________________________________
_____________________________________________________
_____________________________________________________
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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?
_____________________________________________________
_____________________________________________________
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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.
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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.
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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.
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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
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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.
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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.
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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.
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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.
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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 _______________________.
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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 _____________________
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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?
_______________________________________________________
_______________________________________________________
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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 everchanging environment.
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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.
________________________
________________________
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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?
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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.
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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.
MICROBIOLOGY
VIRUSES, BACTERIA, PROTISTS
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ACROSS
2.
8.
11.
16.
18.
21.
22.
23.
24.
25.
26.
You catch a disease and become immune to it in the future is a type of ________.
Spiral shaped bacteria
Used to carry out intracellular digestion.
AIDS – AID stands for _______________
Produced by some bacteria – causes food poisoning
Syphyllis, herpes, warts
Symptoms include discharge and pain upon urination.
When a virus remains inactive in a cell it is said to be ________________
When injected, causes the body to make antibodies
The source of new “spikes” on the influenza virus.
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.
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