Download ModBio11-5Microbiology

OBJECTIVE SHEET
MICROBIOLOGY 1
VIRUSES
1. Demonstrate aseptic technique when handling bacteria.
2. Discuss the evidence used to classify viruses as living or non-living.
3. Identify the stages of the: lytic and lysogenic cycle.
4. Define the following: bacteriophage, retrovirus, viroids and prions.
PROKARYOTES
5. List the characteristics of the Domain Bacteria and the Domain Archaea.
6. Classify bacteria based on gram staining, bacteria shape and how the bacteria
obtain and use energy.
7. Define the following:
flagellum, pili, bacilli, cocci, spirilla, binary fission, heterotrophs, saprophyte,
chemosynthetic and photosynthetic autotrophs, conjugation, transformation,
endospore, toxin, anti-toxin, STI, phagocyte, vaccine.
8. Differentiate between obligate aerobes/anaerobes and facultative
aerobe/anaerobes
5. Give the cause, symptoms and treatment for the following STI’s: AIDS,
Chlamydia, gonorrhea, syphilis, and Herpes II.
IMMUNOLOGY
6. Explain how pathogens cause disease.
7. Describe three ways in which a virus can alter the normal functioning of a cell.
8. State two main functions of the immune system.
9. Explain how non-specific and specific defenses occur in the body.
10. Explain how vaccines are made.
11. Describe how scientific knowledge of viral action and DNA structure have
been applied in the use of recombinant DNA technology.
12. 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?
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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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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 colour 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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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? ____________
_______________________________________________________
_______________________________________________________
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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
the process_______________________________ to make ATP.
oxygen
is
When
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. Prokaryotes that contain peptidoglycan in the cell wall are Gram positive.
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 blue while Gram negative
bacteria without the peptidoglycan 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.
Materials:
Oil Immersion Microscope
Innoculating Loop
A. Bacterial slide Preparation:
Slide warmer
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.
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18. Repeat all these steps with a second sample of bacteria provided.
C. Set up the Oil Immersion Lens on the Microscope
19. Use a clean cover slip and observe your bacteria slides for colour and
shape using oil immersion. Adjust your iris diaphragm to maximize
detail. Make sure that oil does NOT touch any of the other lenses.
20. Fill in the chart below. 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 blue and Gram
negative stain red.
Name of Bacteria
Gram + or Gram -
Shape
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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
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chemical that breaks down starch, similar to the chemical found
in your digestive system that does the exact same thing.
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, rubrum broth, 2 agar plates, tweezers, clear
tape, Q-tip, confetti discs, various antiseptics and disinfectants, various
antibiotics (eg. Amoxicillin, Cephalexin, Novamoxin, Penicillin)
Procedure:
1. Using a Q-tip, contaminate one tip with the bacteria of a peppercorn
sample at the back of the room.
2. With your Q-tip, make streaking motions across your Petri dish lightly
touching the agar. Re-contaminate the Q-tip three times and streak your
plate at 90° angles each time. Try not to damage the surface of the agar
with the Q-tip.
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3. Dispose of the Q-tip in the garbage.
4. On the bottom of the agar plate, divide the area up into 4 quadrants with a
marker and then label the quadrants 1,2,3 and 4 as shown.
5. Soak 4 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. You do not want
them dripping wet, just wet.
6. Use your tweezers to place a soaked disc on quadrant 1,2,3, and 4. 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. Repeat steps 1 to 7 with another Petri dish but use the bacteria from the
red broth if available. Use different agents this time and approach your
teacher about how to use safe techniques before you use the
bacterial broth. (re-read manual pg. 7 procedures #6 and 7)
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 (figure out how you are going to tabulate and design your own
table) and the answers to the following questions:
Questions:
1.
Draw a sketch of your Petri dish 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.
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S.T.I.
SEXUALLY TRANSMITTED INFECTIONS
S.T.I. PRE-TEST
1. Of the following, which is the most common type of STI in BC?
a)
b)
c)
d)
Chlamydia
Gonorrhea
Syphilis
AIDS
2. Which of the following terms means the same as VD or STD?
a)
b)
c)
d)
mumps
STI’s
AIDS
Syphilis
3. Which infection is not caused by a bacterium?
a)
b)
c)
d)
gonorrhea
syphilis
AIDS
Pneumonia
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4. Which statement is false?
a)
b)
c)
d)
STI’s can be transmitted through sexual contact
Sex causes STI’s
Your body does not make antibodies to protect you against STI’s
Even one sexual encounter with an infected person can spread STI’s.
5. The infection most often confused with gonorrhea is:
a)
b)
c)
d)
Chlamydia
Syphilis
Common cold
Diarrhea
6. Untreated gonorrhea can result in
a)
b)
c)
d)
becoming sterile
death
mental retardation
dehydration
7. Which of the following is a first symptom of syphilis?
a)
b)
c)
d)
pain on urination
canker sore at point of infection
skin rash
hair falling out
8. What percent of females have no visible signs or symptoms to warn them that
they have gonorrhea?
a)
b)
c)
d)
80%
100%
0%
50%
9. For which of the following is there no cure?
a)
b)
c)
d)
gonorrhea, Chlamydia
AIDS, syphilis
Herpes II, crabs
Herpes II, AIDS
10. Which of the following is/are 100% effective at preventing transmission of an
STI?
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a)
b)
c)
d)
condom
abstaining
diaphragm
having few sexual partners
11. Why have STI’s become so common?
a) people will not talk about them because it is too personal
b) most of these infections are hard to cure
c) they can be passed on from person to person on contaminated dishes and
clothing.
d) People are not educated about them.
True or False?
A. Catching STI’s over and over again can weaken your immune system. _____
B. Gonorrhea can be caught simply by kissing an infected person. _____
C. In ancient history, many of who were thought to have leprosy, actually had
syphilis. _____
D. Syphilis can kill up to 20 years after being infected. _____
E. The health clinic can treat you for an STI without informing your parents.
_____
Matching
_____syphilis
1. Insects that feed off of pubic area blood.
_____hepatitis B
2. An HPV vaccine prevents cervical cancer
_____ HIV
3. Can cause mental illness if left untreated
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_____ genital herpes
4. No cure for these sores
_____ papilloma virus
5. Can cause cancer
_____ crabs
6. This virus evolves very fast in an individual
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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?
_____________________________________________________
_____________________________________________________
over…
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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 have 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. Explain the life cycle of Malaria.
7. Describe the role of plankton.
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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 centre about the utilization of energy, they very often result in different
organisms using a variety of different structures and ways to perform these life activities.
Here is an introduction to the variety of Life activities performed by organisms.
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 that 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. Mouthparts 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 that 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
kidneys 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 their
own 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 which 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,
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which in turn ejects the fluid to the exterior. Contractile vacuoles play a major role in controlling the water
balance of the paramecium. 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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BEHAVIOUR
The behaviour 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 ‘headon’ 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 behaviour 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 behaviour 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 behaviour” 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 ever-changing 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.
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