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BIO 111 General Biology Peer-Lead Team-Learning (PLTL) Workshop 2 Physics and Chemistry of Life, Macromolecules: Lipids and Carbohydrates Methods of Science Revisited The first 90 minutes of each laboratory class meeting (in room 328 NMM) will consist of a PLTL workshop on subjects addressed in the lecture part of the course. These sessions are a required part of the course and will be conducted by a student peer-leader. Your laboratory class will immediately follow each PLTL workshop. The PLTL workshops will start at 13:00 (1:00 pm) and late arrivals will not be permitted. Laboratory will begin promptly at 14:30 (2:30 pm). Introduction Biology is a synthetic science in that it is built on the foundations and subject to processes of physics and chemistry. Understanding the ways in which living systems are constrained by the laws of physics can provide insights on the ways cells and organisms function. Similarly, living systems are coordinated chemical systems made of atoms and molecules that interact in predictable ways. All cellular life is made of four categories of organic molecules: carbohydrates, lipids, proteins, and nucleic acids. Pre-Workshop Assignment Prior to your laboratory class meeting you should complete the questions given below and bring your completed work to your laboratory class meeting. Activity A. Define the following terms : Write your answers in complete sentences on a separate sheet of paper and be prepared to submit them at the workshop meeting.
- Hydrogen bond
- Ionic bond
- Covalent bond
- pH
- Amino acid
- Fatty acid
- Polysaccharide
- Levels of Complexity
BIO 111 General Biology
- Metabolism
- Growth
- Development
- Evolution
- Genotype
- Phenotype
- Adaptation Activity B. The Physics and Chemistry of Life What are the six elements found in living systems that account for 98% of the total mass of most organisms? Make a table listing each of the six elements you identified above and for each element list the following: atomic number, atomic mass, number of electrons in the K orbital, number of electrons in the L orbital, number of electrons in the M orbital and the number of covalent bonds that could form with other atoms. Element (name and symbol) Atomic Number Atomic Mass K-orbital electrons L-orbital electrons M- orbital electrons Covalent bonds possible List four types of chemical bonds in the order of how strong are they compared to each other in an anhydrous (without water) environment? How do the chemical bonds compare to each other in water? Bond Type Anhydrous strength Strength in water
BIO 111 General Biology Activity D. Fat City Lipids include a diverse group of organic compounds (including fats) that are similar in being hydrocarbons that are non-polar. What does “non-polar” mean and what characteristics make molecules non-polar? Name and describe three different functions that are served by molecules classified as lipids. Phospholipid molecules are lipids that have polar properties. Molecules of this type are the main structural components of all biological membranes, phopholipid bilayers. Draw a ball and stick diagram (in the box) of a generic phospholipid molecule. Show every atom and every chemical bond. If this molecule were placed in water, what part of the molecule would orient toward water molecules? What part of this is non-polar?
PLTL Workshop Problems
Activity 1. The Search For ET Work in groups of six to address the questions and write your responses on the chalkboard. The entire workshop group will then compare answers. Since 1965 when the first close range photographs were taken, NASA has been sending spacecraft to the planet Mars, in part, to search for evidence of life. No one expects to find macroscopic organisms or human-like evidence of life (trash dumps,
BIO 111 General Biology buildings, or footprints). The most recent Mars probes have looked for organic molecules that are unlikely to have formed in a non-living system.
- What kinds of evidence would indicate the presence of life that may be microscopic?
- Can organic molecules form in the absence of life?
- What kind of evidence would indicate the past presence of life on Mars?
- What are the qualities of life?
- What is the evidence that there was life on earth 4.5 billion years ago? Activity 2. The Method of Science The workshop group will be divided into two teams. Everyone should read the following passage and the teams will discuss the questions themselves. The workshop leader will call on individuals alternatively from each team to answer questions. Correct responses will earn the team one point. The following is the complete abstract from “Amnesic effects in mice of four synthetic peptides homologous to amyloid β proteins from patients with Alzheimer disease.” (Flood, Morley and Roberts, 1991): “Immediate post-training intracerebroventricular administration of a synthetic peptide homologous to β protein of brain amyloid, [Gln^11 ] β-(1-28), caused amnesia for footshock active avoidance training in mice in a dose-dependent fashion. This effect was specific to memory processing since the peptide did not cause amnesia when injected 24 hr after training nor did it disturb storage or retrieval of older memories. Shorter fragments of the amyloid β protein consisting of residues 12-28, 18-28, and 12-20 also were amnestic when given intracerebroventricularly, residues 12-20 being least effective. The hippocampus, a brain structure importantly involved in learning and memory, consistently shows severe pathological changes and deposition of amyloid in patients with Alzheimer disease. Immediate post-training bilateral intrahippocampal injection of [Gln^11 ] β-(1-28)produced amnesia at much lower
BIO 111 General Biology peptides homologous to amyloid β proteins from patients with Alzheimer disease, Proc. Natl. Acad. Sci. USA 88:3363-6. Apr 91). This is really the first correlation between the presence of (beta- amyloid) in the brain and the loss of memory, said Rachael Neve, a molecular biologist at U. California at Irvine.” From “Clue to Loss of Memory in Alzheimer’s Reported.” New York Times 16 April 1991, p C10 (Associated Press).
- Is it dishonest for a newspaper to take the information presented in a research article and present it as given above?
- Would it be dishonest if the newspaper article had been the paragraph below (compare this paragraph to the Abstract above and explain why you do or do not think this paragraph is dishonest?): Flood, Morley and Roberts (1991) in a study titled “Amnesic effects in mice of four synthetic peptides homologous to amyloid β proteins from patients with Alzheimer disease” published in the Proceedings of the National Academy of Sciences found that immediate post-training administration of a synthetic peptide similar to β protein of a brain amyloid caused amnesia for avoidance training in mice. This finding involved memory processing since the peptide did not cause amnesia when injected 24 hr after training nor did it disturb retrieval of older memories. The hippocampus, a brain structure importantly involved in learning and memory, consistently shows severe pathological damage and deposition of amyloid in patients with Alzheimer disease. These experimental results suggest a possible direct role of amyloid β protein in the memory loss associated with Alzheimer disease.
- What must a writer do to ensure that their writing is original while giving appropriate credit to the authors of new information or ideas?
- Why is academic honesty important? Is it important that your professors be honest with you?
- What are the consequences of academic dishonesty at Morehouse College?
BIO 111 General Biology Activity 4. Orbitals and Reactivity Work in groups of six. Each group will draw the names of six elements from the “big- bang box”. Each member of your group will address the following questions for one of your six elements and write your answers on the chalkboard to share with the entire group. Yes, consult your textbook or any reference source that you wish.
- What is the total number of protons in each atom of this element?
- What are the number of electrons in the outer-most orbital in a neutral atom?
- What kind of chemical bonds are atoms of this element likely to form?
- How many bonds might form at one time with an atom of this element? Element Protons Outer orbital electrons Chemical bond type Number of bonds possible Activity 5. Solutes in Solutions Do this activity as a team competition. Divide the group into two teams. Each member of one team will be called-on in sequence to answer one item. If a team member misses one answer, the other team begins to answer the next question in sequence. They answer questions until they miss, after which the first team begins to answer again. Each correct answer is worth one point. For each compound pulled from the “solutes” box state the following: a) Will it dissolve in water? b) If it does not dissolve, why not? c) Will it dissolve in acetone? d) Will ions form in solution? e) How many ions will form? f) Which ion is positive? g) Which ion is negative? h) What kind of bonds held the solute atoms together? Compound Dissolve in water If not why not? Dissolve in acetone Will ions form? Number of ions Positive ion Negative ion Bonds in solute
BIO 111 General Biology Activity 7. I Just Ate a Bowl of Rice, now What? Although, carbohydrates and lipids have very different properties and functions in living systems, there are similarities in the chemical processes that build the molecules and break them down. Working in groups of six, pick six molecules (lipids and carbohydrates) from the “rice bowl”. You and the members of your group will address the following questions for each molecule and write your answers on the chalkboard to share with the entire group. a) What is this molecule, carbohydrate or lipid? b) What type of carbohydrate or lipid? c) What are the component molecules of this complex molecule? d) If the components were released first, what are the first bonds that would be broken during digestion? e) What type of chemical bonds are they? f) How does that type of chemical bond hold atoms together? g) What role(s) could this molecule have had in the living organism from which your rice bowl was prepared? h) How might your body use this molecule? Compound What is it? Type? Components? Bonds? Bond type? Bond function? Role? Use in your body? Post-Workshop Assignments Use the following blank table to quiz yourself (or work with a classmate) on the characteristics of biological molecules: Complete the table for each of the following compounds (or make your own list): a) Cane sugar b) Estrogen c) Vegetable oil d) Lard e) Wood f) Potato tuber g) Glucose (IV drip)
BIO 111 General Biology Write the name of the material: In what class of molecules is this? What are the subunits that compose this? What are the characteristics of this class of molecules? What is the function of this material in the living organism? Draw a stick diagram of a typical molecule representative of this group Literature Cited Flood, J.F., J.E. Morley, and E. Roberts. 1991. Amnesic effects in mice of four synthetic peptides homologous to amyloid β proteins from patients with Alzheimer disease. Proc. Natl. Acad. Sci. USA 88(April):3363-3366. Activity 2. Methods of Science was based on a case study developed by Dr. Wasi Siddiqui and modified by L. Blumer 7/2004. Activities 1 and 3-7 developed by L. Blumer 7/2004 and 6/2005. Revised 1/2006 by L. Blumer.
