Back to e-portfolio

Use of New Content Knowledge in Designing Instruction

Reflection

In biology and later in biochemistry we learned how the shape of the protein is imperative to its function.  Should the protein be folded incorrectly due to a mutation, such as the process that occurs in sickle cell, the protein will not function properly.  Proteins are responsible for a variety of functions, including movement, chemical processes within the body and mechanical support.  I used this new content knowledge in designing the following lesson with another cohort member Cory Redding.  A portion of the lesson gives background information explaining the function of biological polymers and the ramifications of what occurs if their make up is altered.  In the lesson itself, Cory and I  utilize our students background knowledge in chemistry.  Students make up oobleck in various combinations so they can study how the make up of the oobleck affects its properties.  This in turn would help them understand how the function of biological polymers would be affected by a shape change.  In addition we have the students use technology to look up information about sickle cell anemia, Tays Sacks and hemophilia.  Part of the discussion would center on aspects of health.  Questions such as "Can these conditions be controlled by living a healthy lifestyle?"  This lesson cuts across the curriculum in biology, chemistry, technology and health and was related to real world issues.  The lesson focused on the enduring understanding that biological phenomena can be analyzed at multiple levels from the molecular to the organism.　This assignment caused me to think about a way to make the abstract more concrete.  I have used it with my students and have found it to be effective. 

I am using the following paper to demonstrate my growth in the application of new scientific knowledge in the design of teaching materials, lesson plans, and or assessments used in my own classroom.　

How this shows growth:

Prior to learning this information I would not have thought to use a lesson on oobleck, which children love, to demonstrate a bioological phenomena.  Previously I used oobleck as an introduction to properties of matter.  It led to discussions of characteristics of matter.  Is it a liquid or is it a solid?  Now I would use oobleck in a more sophisticated format; to demonstrate how changes in this substance affect its function and relate this to how changes in a protein also affect its function. 

Evidence below

Biology Lesson

July 20, 2004

 Background Content and Discussion of Pedagogic Literature

 Biologic Polymers Teacher Background Information 

Polymers are made up of monomers. The three main types of biologic polymers are proteins, polysaccharides and nucleic acids.  Lipids are not considered polymers because they are not composed of component part molecules (Krough, 2005).    

Proteins

Proteins accomplish a multitude of functions within the body and are often referred to as building-block molecules.  They are made up of monomers called amino acid joined together by polypeptide bonds.   Amino acids have a typical structure, consisting of a carbon atom in the middle with an amino group on one side, a carboxyl group on the other and a hydrogen atom attached to the “top.”   What differentiates one amino acid from the other is the side-chain, or “R” group.  The variation in the R position results in twenty different amino acids. 

  While the protein is forming and monomers are lined up in a chain, the correct terminology is a polypeptide.  Once the polypeptide is folded, it is considered a protein.  Below is a diagram of how a protein is synthesized.

www.accessexcellence.org/ RC/VL/GG/images/protein.jpg

The shape of the protein is imperative to its function.  Should the protein be folded incorrectly due to a mutation, such as the process that occurs in sickle cell, the protein will not function properly.  Proteins are responsible for a variety of functions, including movement, chemical processes within the body and mechanical support. 

Polysaccharides

            Polysaccharides are made up of monomers called monosaccharides, or simple sugars.  Examples of monosaccharides are glucose and fructose.  When the monosaccharides link up, a polysaccharide, or complex carbohydrate, is formed.  Polysaccharides are carbohydrates that are polymers.  There are four main types of polysaccharides are starch, glycogen, cellulose and chitin. 

Nucleic Acids

            Nucleic acids are made up of monomers called nucleotides.  Each nucleotide includes a phosphate group, a sugar and nitrogen base.  When nucleotides are linked together, nucleic acids such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are formed.   There may be up to three billion nucleotides linked together to form a copy of DNA in humans, and one copy exists in each of our cells (Krough, 2005).  The function of DNA is to store our genetic information.  RNA’s functions include aiding in the synthesis of proteins and transporting encoded DNA (see figure 1.1).

                                                    www.accessexcellence.org/RC/VL/GG/images/rna.gif

  Sickle Cell Anemia Teacher Background Information

Sickle cell anemia is a blood disorder that primarily affects people of West African descent.  It is an autosomal recessive disorder, meaning that children that receive two copies of the gene will have the disease.  Children that inherit only one copy of the gene will be carriers but generally do not exhibit symptoms.  In an area where malaria is common this is an advantage because having the genetic mutation helped protect people from getting infected with malaria. Unfortunately over time individuals with the heterozygous recessive gene married others with the same recessive trait.  The recessive form of the gene became much more common and more and more people inherited the disease. 

Sickle cell anemia is caused by a genetic change in hemoglobin.  Hemoglobin is a protein that is made up of chains of amino acids.  Its function is to pick up oxygen in our lungs and deliver it to other cells.  It performs this function well unless it is inherited in another form called hemoglobin S.  Hemoglobin S results from a change in one nucleotide that makes up the DNA. The mRNA transcribes the incorrect information and carries it to the tRNA.  In turn, the tRNA will translate and drop off the incorrect amino acid which forms the polypeptide.  This results in a change in the fold of the protein.  Glutamic acid, which is polar and soluble in the watery cytoplasm of the red blood cell, is replaced by valine which is non-polar and non-soluble in the cytoplasm. The valine stacks and precipitates out in spike like formation.  The result of this process is a sickle shaped cell as opposed to the concave discs that are normally found.  Because the capillaries are so tiny, they can become clogged when the odd shaped cells attempt to pass through them.  This can cause pain and damage to tissue and organs.  Sickle cells also have a shorter life span than regular blood cells which can cause chronic anemia.  

The severities of the symptoms of the disease vary from individual to individual.  They cannot be predicted based solely on genetic inheritance.  Some develop life threatening symptoms as infants but others have only mild symptoms throughout their life.  Varying severity of the symptoms can be exhibited at different times.  Factors that can cause the disease to manifest itself are low oxygen, cold temperatures and dehydration. 

“There are several symptoms that warrant immediate medical attention, including the following:

• Signs of infection (fever greater than 101°F or 38.3°C, coughs frequently or breathing trouble, unusual crankiness, feeding difficulties)
• Signs of severe anemia (pale skin or lips, yellowing of the skin or eyes, very tired, very weak)
• Signs indicating possible dehydration (vomiting, diarrhea, fewer wet diapers)
• Other signs (pain or swelling in the abdomen, swollen hands or feet, screams when touched).

Testing can be done to determine if a child has sickle cell disease even before the child is born. The disease cannot be cured but some of its effects can be mitigated. Preventive antibiotics are used, making sure that a person stays hydrated is important, getting proper immunizations, avoiding stress, and proper nutrition are important.”  

http://health.enotes.com/genetic-disorders-encyclopedia/sickle-cell-disease

Goals of Lesson

 Big Ideas

• There are polymers in our body that perform specific functions.
• The biological polymers need to have a certain make up to perform their function.
• Changing a structure on the molecular level influences an organism at the organism level.

Objectives

• The students will identify the three main types of biological polymers and their functions. 
• The students will be able to identify the effects of change in a polymer at the molecular level and how it may influence the organism at the whole body level.

 Students’ Prior Knowledge

Students have been learning about polymers over the course of six days.  The lesson on biological polymers and the effect of their make up on function will occur on day seven.  Prior knowledge from the polymer unit includes:

~ What is a monomer?

~ What is a polymer?

~ Examples of common/ everyday polymers

~ Synthesis / cross-linking of polymers

~ Models of monomers/ polymers (using paper clips) 

Eighth Grade Polymer Unit

Students also have background knowledge from the seventh grade life science course.  A short review will take place at the beginning of the lesson to activate concepts learned the year before.  Prior knowledge includes:

~ Structure of the cell

~ Basic understanding of human body systems

~ Amino Acids/ Proteins (transport, enzymes etc)

~ Monosaccharides/ Polysaccharides (starch, glycogen, etc)

~ Nucleotides / Nucleic Acids (DNA, RNA, etc)

~ Molecules

Part 1 – Identifying Biologic Polymers

Hook and Informal Pre-Assessment – Hand out worksheet with a list of various substances.  Have students circle any substance that contains or is a polymer.  (see attached student worksheet)

Students will work in groups of three and list as many examples of monomers and polymers in their body as they can.  Students will have resource books and web sites to use that include information that will give examples of monomers or polymers in the body.

Suggested web site:

http://pslc.ws/mactest/maindir.htm

Expected Student Responses

Students will take on the role of one biologic polymer (protein, polysaccharide, nucleic acid) and will be responsible for finding examples of their polymer along with its function. (see attached student worksheet)

Expected Student Responses

Jig Saw Activity - Students will share information with original group.  To insure all students have accurate and complete information teacher will fill out data table on overhead. 

Part 2 – Effects of a Change in a Polymer at the Molecular Level

Students are asked to take out their chart with information on the properties of the three polymers that they synthesized and investigated at the start of the unit.

Students will be asked to briefly review the characteristics of the polymers.

Students will be given the specific ingredients for one of the polymers (gloop) and asked to make changes in the ingredients following the guidelines outlined on the student worksheet.  Students will list any changes in the characteristics of the polymer.  (see attached worksheet)

Teacher will call students together and they will share the results of their investigation.

List quantitatively the results of the slime test and the bounce test.

Discuss the changes that were made to get these results.  (i.e. what were the specific ratios and proportions used to get new characteristics)

Students will get into groups of four and asked to research sickle cell anemia using web sites, books, or articles.  Each group will be responsible for researching one of the following questions:

What is sickle cell anemia?

What causes sickle cell anemia?

What effects does sickle cell anemia have on your body?

How do you get sickle cell anemia?

Web Articles: http://kidshealth.org/teen/diseases_conditions/blood/sickle_cell_anemia.html

                           http://www.mayoclinic.com/health/sickle-cell-anemia/DS00324

                           http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_All.html

                          http://www.scinfo.org/Sickleinfosheet2.doc

                          http://www.scinfo.org/powerpt.htm (on line power point presentation)

 Jig Saw 2 - Students will meet with representatives to share what they learned with the other groups. 

Finally, as a whole group we will discuss the findings and how they relate to the polymer investigations. 

Assessment and Homework – Differentiated Expectations

Lower Level

Explain how a change at the molecular level (gene mutation) may affect an organism at the whole body level. (Effects of sickle cell anemia on the body)

Middle Level

Research Tays Sachs disease or Hemophilia.  Explain the causes of the disease and how it affects the body. 

Gifted

Research Tays Sachs disease or Hemophilia and compare their genetic mutations with sickle cell anemia. 

Date: _____________________   

Group Names:

 ___________________________________________________________________________                                                             

Useful web sites:  http://www.mayoclinic.com/health/sickle-cell-anemia/DS00324

                                 http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_All.html

                                 http://www.scinfo.org/Sickleinfosheet2.doc

                                 http://www.scinfo.org/powerpt.htm (on line power point presentation)

                                 http://www.sicklecelldisease-il.org/sections/what/how.html

  What is sickle cell anemia?

What causes sickle cell anemia?

What effects does sickle cell anemia have on your body?

How do you get sickle cell anemia?

Patty McCarrin - September 30, 2007              Back to e-portfolio