I hear, I forget…. I see I remember… I do, I understand -Confucius

1. I hear, I forget…. I see I remember… I do, I understand -Confucius Engineers and scientists can each study biology. Yet, the Ultimate purpose for this study is different for the two groups BYS201

2. The process of science. Observations are made and from those a question is formulated. A hypothesis is developed that is the expected answer to the question. Experiments are designed to test the hypothesis and predictions are made as to what the results will be. These predictions are testable using mathematical equations (statistics). The experimentation begins and the results are evaluated by the statistical methods to determine whether the hypothesis was valid. BYS201

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5. Contrasts between science and engineering BYS201

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7. Expectations for Biological Engineers: The knowledge of biological principles and generalizations that can lead to useful products and processes. 2. The ability to transfer information known about familiar living systems to those unfamiliar. The ability to avoid or mitigate unintended consequences of dealing with any living system Pollution cleaning example BYS201

8. Biology is study of life BYS201

9. What is life? What are the characteristics of living organisms? BYS201

10. Functions and constraints of life • Nutrition (food) • Respiration (energy) • Irritability (response) • Movement • Excretion • Reproduction (multiply) • Growth BYS201

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13. Basis of Chemical activity: The reactivity of atoms arises from the presence of unpaired electrons in one or more orbitals of their valence shells. Octet Rule: BYS201

14. Compounds. Molecules are made of two or more atoms. Molecules made of two or more elements are called compounds. BYS201

15. There are two major ways two atoms can form a compound, covalent bonds and ionic bonds. Covalent bonds occur when the atoms share electrons to complete their outer shell. BYS201

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17. Why are we carbon based life forms? Carbon-carbon covalent bonds are much stronger to take apart than the thermal energy released from cellular metabolic activities or energy in sun light. However, UV light has enough energy to break C-C bonds. BYS201

18. Covalent bonds are much stronger than ionic bonds and are much more difficult to take apart. Physical strength of bonds BYS201

19. Ionic bonds occur when one atom gives electrons to another atom which results in one having a positive charge and the other having a negative charge. The charges attract and hold the atoms together. Highly ionic bonds sometimes create free radicals that are harmful to biological systems BYS201

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21. H2O HO.-+ H+ O3 O2.- Free radicals and cellular aging Atoms or molecules with unpaired electrons Role of Superoxide dismutase BYS201

22. Polar vs nonpolar. Some atoms are very "electronegative". In a water molecule, for example, the oxygen is sharing two pairs of electrons, one each with two hydrogen atoms. However, this is not an "equal" sharing. The electrons are more often associated with the oxygen than with the hydrogens. When they are with the oxygen it is negatively charged and when they are missing from the hydrogens there is a positive charge. So the water molecule has positive and negative poles like a magnet. We say that it is a polar molecule. Nonpolar molecules have atoms that share the electrons equally. BYS201

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24. Polar molecules lead to what is called hydrogen bonding. For example when you have lots of water molecules the partial negative charges are attracted to the partial positive charges. The molecules form a matrix. BYS201

25. It is the hydrogen bonds that make water cohesive so that it forms drops. It also causes the surface tension that allows insects to run across the top of a pond*. http://link.brightcove.com/services/link/bcpid1138370360/bctid1335882656 BYS201

26. Hydrogen bonds make water an excellent heat sink since heat energy must first break the bonds and then excite the molecules (kinetic energy). Calories BYS201

27. The reason ice is less dense than water is because as water cools more bonds form and the atoms are positioned at regular, spacious intervals. Warm water breaks bonds and they become free to more closely associate. BYS201

28. Water as a solvent. When a polar or ionic compound is added to water it can participate in the charge interactions of the hydrogen bonded waters. Each molecule of the polar substance will be coated with waters and hence it is in solution. What happens when a nonpolar substance is added to water? BYS201

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30. Even molecules with nonpolar covalent bonds can have partially negative and positive regions. • Because electrons are constantly in motion, there can be periods when they accumulate by chance in one area of a molecule. • This created ever-changing regions of negative and positive charge within a molecule. • Molecules or atoms in close proximity can be attracted by these fleeting charge differences, creating van der Waals interactions. Eg: graphite, lipids in water, talk, lizards walking on the wall http://www.youtube.com/watch?v=odAifbpDbhs&feature=related BYS201

31. Acids and Bases. Acidity is a measure of the hydrogen and hydroxide ions in solutions. When there are more hydrogens (H+) than hydroxides (OH-) the solution is acidic. When the opposite is true it is basic. When the concentrations are equal it is neutral. pH is a measure of the hydrogen ions in solution and the pH scale is logarithmic. -log[H+] Neutral is a pH of 7. Below seven is acidic and above is basic. BYS201

32. Small shifts in cellular pH play a major role in regulation of biological activity BYS201

33. Chemical reactions. Atoms and molecules can be combined to form new molecules, and molecules can be broken down to simple molecules. BYS201

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35. Energetics of chemical reactions Bioenergetics - various types of energy transformations that occur in living organisms Cells require energy to survive What is energy? Potential energy Kinetic energy Chemical and physical laws govern the biological reactions Laws of thermodynamics and concept of energy: BYS201

36. First law of thermodynamics Energy can neither be created nor destroyed Energy can be transduced or transformed System - open and closed Surroundings E and ∆E ∆ E = Q-W Exothermic and endothermic reactions Since ∆ E for a particular reaction can be positive or negative, it gives us no information as to the likelihood that a given event will occur BYS201

37. Second law of thermodynamics Energy cannot be 100% converted. Every event accompanied by increase in entropy of universe Entropy (S) Relationship of entropy of a system vs its surroundings How can a (Biological) system maintain low entropy? BYS201

38. Free Energy (G): ∆ H= G+T ∆ S ∆G= ∆H-T∆S H= Enthalpy (total energy content of the system ~ ∆E) T=Absolute temp. ∆S = change in entropy Value for ∆G indicates the direction of a reaction Exergonic and endorgonic reactions BYS201

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