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SCIENCE EXTENDED LEARNING MODULES TEACHER PACKET Biology SC.912.L.15.1

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(SCIENCE)

extended learning modules

Teacher Packet

Biology

SC.912.L.15.1

(Curriculum and Instruction2011-2012)

Office of academics and transformation

2012-2013

THE SCHOOL BOARD OF MIAMI-DADE COUNTY, FLORIDA

Ms. Perla Tabares Hantman, Chair

Dr. Martin Karp, Vice Chair

Dr. Dorothy Bendross-Mindingall

Ms. Susie V. Castillo

Mr. Carlos L. Curbelo

Dr. Lawrence S. Feldman

Dr. Wilbert Tee Holloway

Dr. Marta Prez

Ms. Raquel A. Regalado

Mr. Jude Bruno

Student Advisor

Mr. Alberto M. Carvalho

Superintendent of Schools

Ms. Milagros R. Fornell

Chief Academic Officer

Office of Academics and Transformation

Ms. Marie L. Izquierdo

Assistant Superintendent

Division of Academics, Accountability & School Improvement

Office of Academics and Transformation

Dr. Pablo G. Ortiz

Assistant Superintendent

Education Transformation Office

Office of Academics and Transformation

Mr. Cristian Carranza

Executive Director

Department of Mathematics and Science

Office of Academics and Transformation

Introduction

The purpose of this document is to provide students with enhancement tutorial sessions that will enrich the depth of content knowledge of the Biology 1 course. Each tutorial session is aligned to Biology Annually Assessed Benchmarks of the Next Generation Sunshine State Standards (NGSSS) as described in the course description and the Biology Item Specifications and include an ExploreLearning Gizmos activity and/or a science demonstration followed by assessment questions.

The Nature of Science Body of Knowledge (BOK) is embedded in all lessons. Teachers are encouraged to generate an inquiry-based environment where students grow in scientific thinking while creating and responding to higher-order questions.

Prior to the day of the activity

The teachers facilitating the session must read the complete packet prior to instruction to ensure effective implementation of the lesson.

The teachers must review the Biology Item Specifications relating to each activity in order to focus their instruction.

If this is the first time for the facilitating teacher doing this activity, the teacher should try the activity prior to the session to anticipate any problems that may be encountered and to prepare the type of support that he/she needs to provide to the students.

The day of the activity

The topic of the tutorial must be written on the board.

Student prior knowledge must be assessed using a KWL, lead-in/essential questions, or a class discussion.

Always before starting the activity, students must be asked to generate their own hypothesis.

Because the Nature of Science BOK is embedded in all scientific activities, the teacher must make reference to all parts of the process of science as the students work through the activity.

As the students work with the teacher through the Student Guide, the students must answer all questions on the hand-out.

When appropriate, a data table compiling all demonstration data must be drawn on the board for class discussion.

Based on the data of the activity, the teacher should facilitate a class discussion by asking the following questions: 1) What do we observe from the data? 2) How does the data support the expected outcomes? 3) How do you explain the variations in data among experiments? 4) What are some possible errors in this data?

Once the teacher facilitator feels that the students have an in-depth understanding of the concepts, the students with the teacher guidance must be directed to work on the Assessment.

If some or all the students have already done any of these activities, you have the choice of selecting any or all of the activities included in the packet.

Timeline:

Activities with class discussion and assessment 3 hours

Table of Contents

Organisms, Populations, and Ecosystems - SC.912.L.14.52 Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics. (Also assesses SC.912.L.14.6)

Item Specifications3

Teacher Guide 1 - The Immune System4

Activity 1 - The Immune System8

Part A - The Immune System8

Part B - The Immune System21

Item Specifications

Benchmark SC.912.L.14.52 Explain the basic functions of the human immune system, including specific and nonspecific immune response, vaccines, and antibiotics. (Also assesses SC.912.L.14.6)

Reporting Category: Organisms, Populations, and Ecosystems

Standard 14: Organization and Development of Living Organisms

Also Assesses:

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both individual and public health.

Benchmark Clarifications:

Students will identify and/or explain the basic functions of the human immune system, including specific and nonspecific immune responses.

Students will describe the basic function of vaccines and/or antibiotics.

Students will explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspective of both individual and public health.

Content Limits:

Items assessing the significance of genetic factors, environmental factors, and pathogenic agents to health are limited to a conceptual understanding.

Items assessing the mode of action of antibiotics are limited to a conceptual understanding and will not require knowledge regarding a specific antibiotic.

Stimulus Attribute:

Scenarios are limited to those commonly included in a biology course.

Response Attributes:

None specified

Prior Knowledge:

Items may require the student to apply scientific knowledge described in the NGSSS from lower grades. This benchmark requires prerequisite knowledge of SC.6.L.14.6, SC.6.E.7.8, SC.8.N.4.1, and SC.8.N.4.2.

Teacher Guide 1 The Immune System

Preparation

Ensure that the following downloads work:

Teacher Domain: http://www.teachersdomain.org/resource/tdc02.sci.life.stru.immune/

PBS interactive game: http://www.pbs.org/wgbh/nova/aids/immunewave.html

Learning Objectives

Students will identify and explain the basic functions of the human immune system

Students will explain the bodys response system to pathogenic agents

Vocabulary

AIDS: Acquired Immune Deficiency Syndrome; an immunological disorder that leaves the body susceptible to infection and some rare cancers; caused by the virus, HIV

antibody: a protein created by B-cells that binds to an antigen or prevents antigens from entering healthy cells

antigen: any substance that induces a response from the body's immune system; often a fragment of a virus or bacteria or some other substance that the body views as an invader

B cell: one of the many components of the body's immune system; a key player in the production of antibodies

body cell: any cell that the body and the immune system view as belonging to the body

complement: blood proteins that work with antibodies to destroy antigens

helper T cell: a type of white blood cell that initiates an immune response when presented with an antigen

HIV: Human Immunodeficiency Virus; the virus that causes AIDS

killer T cell: a type of white blood cell that seeks out and destroys cells that have already been invaded by a virus or some other substance

macrophage: a type of white blood cell that seeks out and consumes foreign substances; capable of presenting antigens on its surface to other cells of the immune system

mumps virus: one of many types of antigens that the body views as a foreign invader

Lesson Overview

Students will watch a short video clip discussing the transmission of pathogens and the bodys response. Working in small groups, they will play (or watch) an interactive game to review the process by which a virus attacks healthy cells. Students must answer questions utilizing vocabulary words.

Suggested Lesson Sequence

1. Engage: (15 minutes)

Show video clip Immune Cells In Action from Teachers Domain: http://www.teachersdomain.org/resource/tdc02.sci.life.stru.immune/

Have students think about and respond to the questions provided. You may allow them to work with a partner and discuss their reasoning:

2. Part A: (60-90 minutes)

Review of Immune System (Whole class)

Using the Background Information in the student packet, please use COMMON CORE STRATEGIES, have students CODE THE TEXT and proceed with discussion of the coded text.

Rotations

It is important to use an ONLINE CLOCK so that students know that each station is timed.

At the end of Rotations, all groups will be assigned a station to report on to the class.

Rotation #1 - Venn diagram

Materials:

Glue or scotch tape

Scissors

Group students in teams of 4. Have students collaborate with each other as they complete the Venn diagram. Have a pair of scissors at the station and enough copies so that students can cut the labels and paste them onto their Venn Diagram.

Rotation #2 - Vocabulary

Have students collaborate with each other as they complete the Vocabulary exercise. Have a pair of scissors at the station and enough copies so that students can cut the labels and paste the correct term to the correct definition.

Rotation #3 - Petri dishes colonies

Materials:

Post-it labels

scotch tape

glue

Group of students will label the Petri dish where you observe Antibiotic resistance.

Students will also read the article titled, What is Resistance to Antibiotics? and answer questions 1 7. Remember: There must be discussion through accountable talk for this activity to hold the rigor it deserves.

Rotation #4 - Group Vocabulary

Students in this group will complete the vocabulary sheet together.

Class Activity

Complete handout and discuss with students.

3. Part B: (45 minutes)

A. You will run the Virus Attack Game from PBS (http://www.pbs.org/wgbh/nova/aids/immunewave.html) to the whole class if a computer lab is not available.

B. Choose two students to demonstrate trial one for the class.

C. Continue with another 6 pairs of students restarting and playing the game during which time they are answering the provided questions.

D. Allow students to click on the tabs at top of screen to help them answer the questions.

E. Ask students if they can identify the various actors in the game.

F. Vocabulary definitions are provided in the Student Packet in order to assist in the answering of the questions.

G. Make sure that students know to access the tabs on the game screen for additional information throughout the game.

4. Evaluate (30 minutes - Optional)

Students will prepare a presentation (e.g., a comic strip, song, or other creative media) utilizing all of the vocabulary terms to depict the story of what happens when a pathogen invades a healthy body.

5. Assessment (20 - 30 minutes)

Students will individually complete the exit ticket individually. TIME IT. When completed, have each student present one of the problems but involve the rest of the class so there is discussion amongst everyone.

Scientific Background

The immune system is a collection of molecules, cells, and organs whose complex interactions form a defense network capable of protecting the body from organisms that cause disease. In general, the immune system can be divided into two distinct, though overlapping, subsystems: the innate system and the acquired system.

The innate immune system provides generalized protection against infection. Immune cells like the macrophages, for example, are very good at cleansing the body of invading organisms whenever they happen upon them. They have little ability to distinguish between self and non-self, however, and may engulf one of their own cells as readily as a foreign cell. These cells will also respond in the same manner no matter how many times they encounter a particular organism; in other words, they do not adapt and improve their effectiveness against previously encountered foes.

In contrast, the cells of the acquired immune system are able to distinguish foreign cells from self, and can distinguish between different types of foreign cells as well. In addition, some acquired immune system cells establish a "memory" for each invading organism they encounter. This is why for example, if you have fought off a certain type of infection -- like the mumps -- on one occasion, your body retains its ability to recognize and quickly mount a defense if subjected to that type of virus in the future.

Cells called lymphocytes are key to the acquired immune system response. There are two types of lymphocytes: B lymphocytes and T lymphocytes. These cells are always on the lookout for foreign cells. When they encounter them, B lymphocytes respond by producing antibodies -- large proteins that destroy or otherwise interfere with the vital activities of foreign cells. T lymphocytes, when they identify a target cell based on its chemical signature, either actively kill the invader using powerful chemicals, or secrete chemicals that attract macrophages that will eat the offending cell.

Importantly, B lymphocytes give rise to two types of daughter cells: plasma cells and memory cells. Plasma cells do little more than produce antibodies; however, they do so prolifically. A single plasma cell is capable of producing 30,000 antibody molecules each second. Memory cells also produce huge quantities of antibody molecules, but more important is their role in "immune memory." Memory cells are extremely long-lived and retain the ability to recognize and fight invaders they've seen before -- often for as long as the host organism remains alive.

Selected Web Resources

Gizmos - www.explorelearning.com:

Virus Lytic Cycle

Disease Spread

Homeostasis

Activity 1 - The Immune System

Engage

Vocabulary: AIDS, antibody, antigen, B cell, body cell, complement, helper T cell, HIV, killer T cell, macrophage, mumps virus.

Watch a short video clip Immune Cells in Action (5 min) http://www.teachersdomain.org/resource/tdc02.sci.life.stru.immune/

Work with a partner and respond to the following questions.

1. If our antibodies protect us from disease, then why do we keep getting colds? Answers will vary

2. How do you think vaccination works to protect you? Answers will vary

Part A - The Immune System

Review of the Immune System:

Read the Background Information and use COMMON CORE STRATEGIES to CODE THE TEXT. Be prepared to discuss what you have read.

Background Information:

Homeostasis is the ability of an organism to maintain a stable internal environment. Diseases can disrupt this stability. Your immune system protects your body from disease.

Your body has three different lines of defense against pathogens.

The immune system includes two general categories of defense mechanisms against infection.

Nonspecific defenses guard against infections by keeping most things out of the body.

Specific defenses track down harmful pathogens that have managed to break through the bodys nonspecific defenses.

To cause disease, a pathogen must invade the body. Your body has barriers to keep this pathogens out. Skin provides a protective barrier. Mucous membranes line up interior surfaces that come into contact with the environment. Pathogens that are swallowed are likely to be destroyed by your stomach acids. Sweat and tears contains salts, acids, and enzymes that help kill pathogens in your skin and eyes.

The inflammatory response is the bodys response to tissue damage. As soon as pathogen enters your body, damaged tissue releases chemical signal. Blood vessels expand. What is a consequence of this? Plasma carries macrophages that engulf and destroy pathogens during phagocytosis If infection persists, body may increase temperature resulting in a fever.

The immune response attacks specific pathogens using specialized cells and proteins. T cells are white blood cells that attack and kill harmful bacteria. B cells are white blood cells that make antibodies. An antibody is a Y-shaped protein that attaches to a specific foreign substance, known as an antigen. bind to the pathogen's membrane proteins cause pathogen to clump together weaken the pathogen's membrane

Active Immunity: Results from exposure to a specific pathogen Naturally Vaccination B cells remain capable of producing antibodies specific to that pathogen reducing the chance that the disease could develop a second time. A vaccine is a weakened form of a pathogen.

Passive Immunity: Created by transferring antibodies made by one organism into another Snake bite Often acquired before birth or during nursing

Antibiotics are drugs used to fight bacterial infections Kill or prevent their reproduction. Antibiotic resistance has become a problem in many parts of the world.

Rotation # 1

Using the Venn Diagram below, compare and contrast the given specific and the nonspecific immune responses. Cut and glue each response onto the Venn Diagram.

Specific Immune ResponseNonspecific Immune Response

(Body is exposed to bacteria/virus and builds defenses takes timeProduction of interferon, which prevents viral replication (not a specific virus)Mucus and hair in your respiratory pathwaySweat attacks bacterial cell wallsSkinIf you get infected again, your body remembers which antibodies to produce and you get healthy faster secondary responseTakes time to build antibodies and for them to workImmune cells recognize the invader and begin to produce Antibodies that destroy the invader this is the primary response)

Rotation # 2 Vocabulary

DIRECTIONS: Collaborate with a partner and complete the Vocabulary exercise. Use a pair of scissors, CUT THE LABELS and paste the correct terms to the correct definitions. At the end of Rotations, all groups will present to the class.

Acquired Immune Deficiency Syndrome; an immunological disorder that leaves the body susceptible to infection and some rare cancers; caused by the virus, HIV

A protein created by B-cells that binds to an antigen or prevents antigens from entering healthy cells

Any substance that induces a response from the body's immune system; often a fragment of a virus or bacteria or some other substance that the body views as an invader

One of the many components of the body's immune system; a key player in the production of antibodies

Any cell that the body and the immune system view as belonging to the body

Blood proteins that work with antibodies to destroy antigens

A type of white blood cell that initiates an immune response when presented with an antigen

Human Immunodeficiency Virus; the virus that causes AIDS

A type of white blood cell that seeks out and destroys cells that have already been invaded by a virus or some other substance

A type of white blood cell that seeks out and consumes foreign substances; capable of presenting antigens on its surface to other cells of the immune system

Mumps virus: one of many types of antigens that the body views as a foreign invader

(Complement) (Body cell ) (Antigen) (Antibody) (AIDS)

(Macrophage ) (Killer T cell ) (HIV) (Helper T cell )

Rotation #3 - Petri dishes colonies

Label the Petri dishes colonies where you observe Antibiotic resistance.

Collaborate with your group to answer the questions after reading the Handout below titled What is Resistance to Antibiotics?

1. What is Resistance to Antibiotics?

2. Why Does Resistance Evolve so Quickly?

3. Expand on why human behavior actually contributes to the capacity for resistance to antibiotics so that it evolves more rapidly.

4. How can antibiotics be overused?

5. How can antibiotics be misused and what effects can that have on Human populations?

6. Bacteria Biology + Current Human Behavior = Fast Evolution

How have these two factors helped speed up the evolution of resistance?

7. What is the Future of Antibiotics?

What is Resistance to Antibiotics?

There are several ways to address this question. First of all, there is a prevalent misconception that antibiotics no longer work because the people who take the drugs have developed a tolerance for the drug. This is not the case. Humans do not develop a tolerance for antibiotics. Antibiotics work by inhibiting or killing the bacteria living inside of us. The reason they no longer work (i.e. we do not get better after taking the antibiotic) is that the bacteria are no longer inhibited/killed by the drugthey are resistant to the effects of the antibiotic.

So, back to our question, what is resistance to antibiotics? Let us first address this question physiologically. There are several ways that bacteria resist the effects of antibiotics. Some resistant bacteria inactivate the antibiotic by destroying or modifying the drug itself so that it is no longer toxic. Some resistant bacteria pump the drug out of the bacterial cell so that the concentration of the drug is too low to be effective. Still, other resistant species have an altered form of the target site of the drug (the place on the cell where the drug binds), so the antibiotic cannot find its target. These are examples of the types of resistance characters that bacteria use to fight antibiotics.

Now, let us address this question on a different level: evolutionarily. What has happened to make these bacteria resistant to antibiotics? Have individual bacteria developed a tolerance to the drug? Have they physiologically acclimated to the presence of the antibiotic so that it no longer affects them? No. What has happened is bacterial evolution.

Mutations that allow the bacteria to resist the effects of the antibiotic occur and have a selective advantage. These mutations have the type of effects that were described in the previous paragraph (for example, there is a mutation that results in an altered form of the target site). These resistance characters are often simple mutations (i.e. changes in a single gene). The result is that resistant bacteria differ genetically from their susceptible ancestors.

So what happens if a bacterial cell has a mutation that allows it to resist the effect of an antibiotic? If that bacterium is in the presence of the antibiotic, then it will have an advantage: the drug will not kill it! It will be able to reproduce, while the susceptible bacteria (which are inhibited or killed by the antibiotic) will not. In the presence of the antibiotic, the resistant mutant has a selective (reproductive) advantage over normal cells. Originally, most or all bacteria in the population were susceptible to the antibiotic4. Over many generations, the resistant type will make up a greater and greater percentage of the population. Eventually, most or all of the individuals in the bacterial population will be resistant to the antibiotic. The population has evolved resistance due to natural selection by antibiotics: the genetic structure of the population has changed, from susceptible to the antibiotic to resistant to the antibiotic.

Why Does Resistance Evolve so Quickly?

Bacterial populations can evolve resistance very quickly. For example, in one hospital, initially 5% of the strains of staphylococcal bacteria were resistant to the antibiotic ciprofloxacin. Within one year, 80% of the bacterial strains were resistant. From 5% to 80% in one year! Why do bacterial populations evolve resistance so quickly? There are two basic reasons:

1) In general, bacteria have the capacity to evolve quickly

2) Humans are helping them to evolve even faster Bacteria Biology

There are several aspects of bacteria biology that contribute to their capacity for rapid evolution. Bacteria, relative to humans, have very short generation times. A generation time is the time it takes to go from one generation to the next. For example, in humans, it takes on average about 20 years to go from the birth of a child to the birth of that childs child. Therefore, the generation time for humans is approximately 20 years. Contrast this with the average bacterial generation time of hours or even minutes! Under favorable conditions, a single bacterial cell will very quickly reproduce into a colony containing many generations of its offspring and their offspring. These colonies can have so many individual cells that, within hours or days, it will be large enough to see with the naked eye. Organisms with fast generation times, like bacteria, have the capacity for very rapid adaptation to a changing environment. Since evolutionary change occurs across generations, organisms with fast generation times (like bacteria) can evolve much faster than organisms with slow generation times (like humans). Some bacteria species can go through thousands of generations in a single year.

Bacterial populations are also very high in numbers and are quite genetically variable. Mutations are the primary source of genetic variation. Mutations (accidents in DNA replication) are rare events. In bacteria, a mutation at a particular gene occurs on average once in about every 10,000,000 cell divisions. Since bacteria are so numerous and divide so often, even these rare events actually occur quite often. As an example, E. coli cells in a human colon divide 2 x 1010 times every day. That means that every day in an E. coli population, approximately 2000 cells will have a mutation at a particular gene5. So, even though mutations are rare events, they occur often enough in bacterial populations to create a lot of genetic variation within populations.

Mutation is not the only way that a bacterium can acquire a resistance gene. Bacteria have three other methods of acquiring genes that sexual organisms (like us) do not have. Bacteria can pick up pieces of DNA (containing genes) from their environment (transformation), they can obtain a gene from another bacterium (conjugation), and genes can also be transferred to a bacterium by a virus (transduction). So, even if a resistance gene does not occur through mutation, it can be acquired through one of these methods. To summarize, bacterial populations evolve resistance to antibiotics so quickly because of their fast generation times, large population sizes, and unique methods of gene acquisition. These are some of the reasons that bacteria have been so evolutionarily successful.

Human Behavior

The second reason that bacterial populations evolve resistance to antibiotics so quickly is that several aspects of human behavior actually contribute to their capacity to evolve rapidly. Understandably, when antibiotics first became available, people started to use them. Today, antibiotics are overused, and unfortunately antibiotics are often misused.

Overuse:

It has been estimated that nearly half of all medical prescriptions for antibiotics in the U.S. are unnecessary. Many doctors prescribe antibiotics under pressure from their patients, even if the antibiotic is not warranted (e.g. for a viral infection). Direct-to consumer marketing by pharmaceutical companies can also lead to inappropriate demand for antibiotics by patients.

Almost half of all antibiotics produced in North America and Europe are given to livestock; most are given not to fight infection, but prophylactically to promote growth in healthy animals. There is growing evidence that this use of antibiotics in livestock leads to resistance in human bacteria.

It is currently trendy to include antibacterial agents in common household cleaning products (even hand lotion!). It is becoming more and more difficult to find cleaners without antibacterial agents.

Misuse:

Medical doctors, including veterinarians and dentists, often incorrectly prescribe antibiotics: they prescribe the wrong antibiotics or the incorrect dosage of an antibiotic for a particular infection; they prescribe antibiotics for non-bacterial infections (e.g. colds, coughs, or influenza); they prescribe antibiotics prophylactically (in a low dosage for months at a time to prevent future infections; for example, for young children with a history of multiple ear infections).

Many doctors also prescribe broad-spectrum antibiotics, which kill many different types of bacteria, rather than run a diagnostic lab test so they can prescribe a narrow spectrum antibiotic that would specifically target the bacteria causing the infection. In many other countries, antibiotics are freely available over the counter, without a doctors prescription, leading to widespread misuse. Patients themselves also contribute to the problem when they feel better after a few days, and then stop taking the antibiotics, instead of continuing with the full cycle prescribed to them. In a 1995 Gallup poll, it was estimated that more than half of American adults taking antibiotics failed to complete their prescribed dosage. Compounding all of these problems, the pharmaceutical industry (until very recently) had all but stopped research and development of new antibiotics.

Bacteria Biology + Current Human Behavior = Fast Evolution

How have these two factors helped speed up the evolution of resistance? In essence, we are exerting extremely strong selection pressures on these bacteria by our heavy use of antibiotics. Bacteria are continuously exposed to antibiotics, and this has created very strong selection on these populations to evolve resistance. The more exposure to antibiotics that resistance. The rate that evolutionary change occurs depends directly upon the strength of natural selection imposed. Strong selection leads to rapid evolution. Antibiotics do not just kill the bacteria species that we want them to act on (i.e. the bacteria causing the infection we are trying to get rid of). Antibiotics also affect a lot of bacteria that are beneficial to us, or that are commensal with us (neither harmful nor beneficial). This decreases the population sizes of these other bacteria, which reduces the competition for the harmful bacteria that survive. This lack of competition for resources allows the surviving resistant bacteria to do very well. In addition, by using antibiotics incorrectly, we are giving the bacterial populations the opportunity to adapt quickly. For example, if you take an antibiotic correctlyin an adequately high dosage and for the entire cyclemost of the bacteria in your system will be killed. By greatly reducing the population size of the bacteria, you greatly decrease the chance that any one bacterium will mutate to a resistant form. However, if you incorrectly take the antibioticif you stop taking it after a few days or if the dosage is not high enoughmore of the bacteria will survive6. Higher numbers of bacteria means a greater chance that a resistance mutation will occur in any one of the bacterial cells. When these mutations do occur, they rapidly increase in the population, due to the very strong selection pressure exerted by the presence of the antibiotic.

In conclusion, the combination of several aspects of bacterial biology (fast generation time, high population sizes) and human behavior (heavy use of antibiotics, misuse of antibiotics) has led to an ever-increasing problem of bacteria resistant to our only means of controlling them.

What is the Future of Antibiotics?

Can we stop the evolution of resistance? Because of their quick generation times and high numbers, bacteria have a very high capacity to quickly adapt to changing environments. We cannot change the biology of the bacteria. As long as we expose bacteria to antibiotics, they will evolve resistance to them. However, we can slow down the evolution of resistance by modifying human behavior.

What can be done to slow down the evolution of resistance?

First, decrease the selection pressure on bacterial populations by decreasing the overall use of antibiotics. Researchers are recommending prudent use of antibiotics (see website of the Alliance for the Prudent Use of Antibiotics). Doctors and patients need to be educated about when and how to use antibiotics appropriately. Antibiotics should not be prescribed for viral infections, such as the common cold. For minor bacterial infections, a period of watchful waiting for a day or two to see if the infection will clear on its own has also been recommended. Scientists are also recommending that the agricultural industry discontinue the use of antibiotics in livestock and on crops, especially those antibiotics that are used to treat disease in humans (see website of the Union of Concerned Scientists).

Second, stop giving bacteria extra opportunities for mutations (i.e. use antibiotics appropriately). When an antibiotic is necessary, the most appropriate antibiotic should be prescribed based on the results of laboratory tests to confirm the precise bacterium causing the infection. Often, a doctor will prescribe an antibiotic without conducting a laboratory test to determine the bacterial species causing the infection. If the antibiotic is not appropriate, and the patient does not get better, he/she then comes back for a different prescription. In this case, all of the bacteria in the patient were unnecessarily exposed to an inappropriate antibiotic. When possible, narrow-spectrum antibiotics should be used, rather than a broad spectrum antibiotic, which affects many different types of bacteria.

Antibiotics need to be taken in strong enough dosages to kill all the bacteria causing the infection, and they need to be taken responsibly: each dose should be taken on time, and all doses (i.e. the full cycle) should be taken. Doctors and pharmacists should be educated about responsible usage, and they should actively encourage their patients to take antibiotics responsiblyexactly as prescribed, and for the entire course. Patients should not demand antibiotics from their doctors.

Third, reduce the spread of resistant bacteria from one person to another. This can be done with the same techniques used for controlling the spread of diseases themselves better hygiene, clean water, vigorous hand washing, etc. The agricultural industry can also help to stop the spread of resistant bacteria by not using the same antibiotics in animals that are also used in humans (to avoid, for example, transferring resistant bacteria to humans in the food that we eat).

Finally, more research is needed. Research on the optimal use of antibiotics will be necessary. It is still unclear exactly how to decrease the selection pressure on bacterial populations. The above suggestions can only help, but more research about how bacterial populations respond to antibiotics is still needed. Also needed is basic research on microbial biology: physiology, genetics, ecology, and evolution. Understanding basic biological\ processes in these organisms will help to develop new drugs and treatment protocols. Most new antibiotics these days are modified from older ones. Because these drugs are so similar to older varieties, resistance evolves very quickly. Research and development of completely new antibiotics will also become increasingly important. Pharmaceutical companies have started to respond to this need, but since it can take up to ten years for a new drug to be approved for use in the United States, there will be a lag time before new drugs will become available.

Rotation # 4

STUDENTS: Use the vocabulary words below and fill them into the correct blank.

acquired antibodiesimmune pathogens

antigens bacteria infectious second

active immunity firstinnate white blood cells

1. Organisms, such as some bacteria and substances such as viruses that cause disease are called ____________________________

2. The system is the bodys defense system. _______________

3. The immune systems ____________line of defense against infectious diseases includes the skin.

4. The immune systems line of defense _________includes the two types of immune response.

5. ______________are carried in the blood to fight infections in the body.

6. All living things are born with a(n) ____________ immune response.

7. Non-living substances that are foreign to the body and trigger an immune response are called _______________.

8. In the first process of an acquired immune response, B cells make substances called _______________that bind to antigens.

9. All acquired immune responses help give you _______________

Class Discussion

1. How is sweat part of the immune system?

_________________________________________________________________________

2. How does a B cell tell the difference between an invader cell and a body cell?

_________________________________________________________________________

3. What is the importance of the body keeping memory B cells if the antigen the cells remember is no longer present?

_________________________________________________________________________

4. Explain the difference between an innate response and an acquired response.

_________________________________________________________________________

_________________________________________________________________________

5. For each of the descriptions below, state the type of transmission method that could have led to contracting an infectious disease.

A. You are at a barbeque party and become ill eating undercooked meat.

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

B. While on a hiking trip your friend is bitten by a small animal. The next day he becomes ill. _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

C. At a movie, the person behind you seems to be sneezing every five minutes. A couple of days later you develop a cold.

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

D. At the end of a soccer game, you shake hands with the other team. A few days later you become ill.

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

6. You go to the doctor feeling very tired and run down. The doctor takes a blood sample for tests and checks your vital signs such as blood pressure, breathing and pulse. Later you receive a call from your doctor and she says you have an infection. What did the blood tests reveal about the number of white blood cells present in your blood?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

Part B - The Immune System

Today we will explore the concept by playing a game called Fighting Back: http://www.pbs.org/wgbh/nova/aids/immunewave.html

Play the Virus Attack Game: It is an interactive game that allows students to distinguish some aspects of non-specific and specific defenses. It introduces terms such as macrophage, helper T-cell, B-cell, plasma cell, antibodies.

You may play this on individual computers or the teacher may run it on one computer and ask for volunteers. Each trial times out at about 5 minutes.

In Fighting Back, the immune system fights one of the many battles that it engages in each and every day to keep the body healthy. Several pairs will be called upon to manipulate the game controls. Whether you are called to run the game or not, you must be watching so that you can answer the following questions. (Use your provided vocabulary terms to help you):

Vocabulary

AIDS: Acquired Immune Deficiency Syndrome; an immunological disorder that leaves the body susceptible to infection and some rare cancers; caused by the virus, HIV

antibody: a protein created by B-cells that binds to an antigen or prevents antigens from entering healthy cells

antigen: any substance that induces a response from the body's immune system; often a fragment of a virus or bacteria or some other substance that the body views as an invader

B cell: one of the many components of the body's immune system; a key player in the production of antibodies

body cell: any cell that the body and the immune system view as belonging to the body

complement: blood proteins that work with antibodies to destroy antigens

helper T cell: a type of white blood cell that initiates an immune response when presented with an antigen

HIV: Human Immunodeficiency Virus; the virus that causes AIDS

killer T cell: a type of white blood cell that seeks out and destroys cells that have already been invaded by a virus or some other substance

macrophage: a type of white blood cell that seeks out and consumes foreign substances; capable of presenting antigens on its surface to other cells of the immune system

mumps virus: one of many types of antigens that the body views as a foreign invader

Explain:

What Happens

1. What is the enemy? The enemy in its war is a nasty little virusa mumps virus.

2. Explain what the enemy is doing. That virus quickly finds and enters a healthy cell within the body, where it uses that cell's machinery to make many copies of itself.

3. How does the body respond to the enemy? Within the body, a macrophage determines that these viruses are the enemy and moves in toward one of the invaders. The macrophage devours the virus and rips the virus apart.

4. Once the enemy has been destroyed what remnants of the enemy can be observed? The macrophage then displays fragments of the virus, called antigens, on its surface.

5. Initially, is the body able to destroy the enemy faster than they reproduce? Although the macrophage at this point is able to destroy more and more viruses, there is no way it could do so faster than the viruses are being made. Something else has to be done.

What Happens (2)

6. When the body realizes that it cannot destroy the enemy fast enough, it calls in the special forces. Explain what the special forces are and how they must be specialized. The macrophage seeks out a helper T cell. Not from any helper T, though. The cell has to recognize the fragments of the virus on the macrophage's surface.

7. Explain the result of the combining of the bodys first line of defense with the special forces? Once the macrophage encounters such a T cell, it and that T cell become united. The connecting of these cells sets into motion a series of eventsevents that, through a multifaceted yet focused attack, lead to the annihilation of the mumps viruses.

Fighting Back

How the Viruses were Wiped Out

8. Explain how the Killer T cell comes to be. Upon binding with each other, the macrophage and helper T cell release chemicals that send special immune cells into action. These chemicals stimulate the production of helper T cells and macrophages. They also stimulate the production another type of T cell: the killer T cell.

How the Viruses were Wiped Out (2)

9. Explain the chain of events initiated by the new Killer T cells that result in the production of millions of antibodies. The newly-created helper T cells take a different approach to the invaders. The helper Ts release their own chemical message in order to stimulate the production of B cells, another very important player in the immune system's counter attack. These B cells transform into plasma cells which, in turn, flood the body with millions upon millions of antibodies.

How the Viruses were Wiped Out (3)

10. How do antibodies react to the enemy? How is this behavior different than that of macrophages? Like macrophages, antibodies seek out foreign invaders. Unlike macrophages, they're very selective about what they attack. The ones produced by this last batch of B cells are after the strain of mumps virus that intitiated the counter attack, and only that strain. Many of these antibodies attach themselves to any mumps viruses they encounter. Attached antibodies acted as flags that say, "Here's one!"

How the Viruses were Wiped Out (4)

11. Explain how antibiodies help macrophages? Macrophages, now more abundant (thanks to the chemical released by your macrophage and the helper T), consume the flagged viruses. Sure, the macrophages would have gone after the viruses without the help of antibodies, but with the antibodies' help, they find and destroy the viruses much more efficiently.

The flags also attract molecules called complements. Complements seek out any antibody-virus combinations and pierce the viruses, thus killing them off.

How the Viruses were Wiped Out (5)

12. Explain what types of cells remain after the virus has been eliminated and how this will help protect the body if the enemy comes again. Within the span of a few days, the virus that first entered your body and its decendants are completely wiped out. After the final battle, the numbers of antibodies, macrophages, B cells, and helper and killer T cells decrease dramatically. What remains, though, are memory B cells and memory T cells. If the virus ever enters the body again, these will quickly move into action and most likely wipe out the invader before it ever gains a stronghold.

Battling AIDS

Say: You've seen how the immune system successfully fights invaders such as the mumps virus.

13. Why isn't it able to do the same with HIV? The reason is that the virus attacks the immune system's T cells, thus disrupting the body's immune response. Still, the immune system puts up a valiant fight, producing a billion new cells every day to combat the virus. A billion isn't enough, though, because a billion copies of the virus are also produced every day.

The two forces continue to fightday after day, month after month, sometimes year after yearuntil the immune system exhausts itself. Once this happens, the number of T cells drop dramatically. And with this vital component of the immune system missing, the body is left susceptible to other diseases.

Assessment - The Immune System

A. Create and present a comic strip, song, or other creative media utilizing all of the vocabulary terms to depict the story of what happens when a pathogen invades a healthy body.

Allow students to show their creativity while using all the vocabulary words to show and explain the concept involving a virus invading a healthy body/organism.

B. Quiz

1. Which of the following is not part of the bodys first line of defense against disease?

A. Vaccine

B. Skin

C. mucous membrane

D. tears

2. Which substance produced by the immune system is involved in both active immunity and passive immunity?

A. Antibiotic

B. Antibody

C. Vaccine

D. mucus

3. How do macrophages protect you from disease?

A. They prevent pathogens from entering our body

B. They prevent bacteria from reproducing

C. They engulf and destroy pathogens

D. They teach your immune system to make antibodies

4. How do macrophages protect you from disease?

A. They prevent pathogens from entering your body

B. They prevent bacteria from reproducing

C. They engulf and destroy pathogens

D. They teach your immune system to make antibodies

5. Antibiotics are used to treat some infectious diseases. Which pathogens cause these diseases?

A. Bacteria

B. Viruses

C. Toxins

D. Fungi

6. By which process does your immune system respond to tissue damage?

A. phagocytosis

B. immune response

C. inflammatory response

D. allergic reaction

2012-2013 Extended Learning ModulesPage 1

BiologySC.912.L.14.52

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