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Orientation to Bio & Chem

Orientation to Bio & Chem. By the end of this class you should understand:. The organization of the fields of science Characteristics common to all living things The organization of living things, and humans in particular The nature of atoms, bonds, and polarity

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Orientation to Bio & Chem

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  1. Orientation to Bio & Chem

  2. By the end of this class you should understand: • The organization of the fields of science • Characteristics common to all living things • The organization of living things, and humans in particular • The nature of atoms, bonds, and polarity • The four major macromolecules found in living things including humans

  3. Biology is an Integrated Science • To understand biology well, one must also understand: • Chemistry • Physics • Math • Statistics

  4. Science! Source: xkcd.com

  5. Organization of Living Things • All living things are highly organized into levels of organization • More complex organisms are organized into more levels • Some living things are only one cell • Some living things do not have organs

  6. Smallest “unit” of life? • A cell is the smallest thing that is alive • It is made of things that are not alive • It meets all the criteria of being alive • Huge variety of cells

  7. Consider a car • A car is made of many parts • Each part is made of materials • Only the complete car will drive around • Cells are alive but made of nonliving things just as cars can drive but are made of parts that cannot

  8. Characteristics of Life • Maintain homeostasis (WTF is that?) • Acquire energy and raw materials • Excrete waste products • Respond to environment • Grow and reproduce • Made of macromolecules (WTF are those?)

  9. WTF are these? • Homeostasis: the process of maintaining a constant internal temperature despite changes in external environment • Example: body temperature • Macromolecules: large molecules made mostly with carbon. Refers to nucleic acids, proteins, sugars, and fats.

  10. Macromolecules • To discuss macromolecules, we will have to explore some chemistry • Everything you’ll need to know about chemistry will fit on these few slides • I promise!

  11. The Basics • All matter is made of atoms • Every atom has a nucleus with at least one proton and usually some neutrons • Protons exert a + charge around them • Neutrons have no charge • These + charges attract electrons which each have a – charge • Electrons are way smaller so they zoom around really fast and can’t hold still

  12. Chemistry is Electron Behavior • The number of protons determines what element it is • Where it goes on the periodic table of the elements • The reason this matters is because there are fixed slots the electrons fit into, and electrons “want” to fill the slots if possible • Atoms will sometimes donate or receive electrons • Ionic bonds • Other atoms will share electrons to fill the slots • Covalent bonds

  13. Why Does This Matter?? • Sometimes covalent bonds are uneven • Electron spends more time on one end than the other • Anyone who’s shared custody of children knows sharing is often uneven! • This means the atom with more than 50% time is slightly negative and the atom with less than 50% is slightly positive • This is a polar bond and may make the molecule a polar molecule

  14. Example of Polar Molecule: • Water! • Water dissolves salt (ionic bonds) because the positive and negative atoms mix with the positive and negative charges in the water • This means water (and other polar chemicals) are slightly “sticky”

  15. Three questions: • Why is water “sticky” when you can slip on it? • What is a very sticky liquid? • What is a very not-sticky liquid?

  16. Best Answers: • All liquids are slippery to some degree • Also note: ice is only slippery if it has a layer of water on the outside • Honey, syrup, molasses: all have sugar in them! • Oil, grease: all have lipids which are nonpolar!

  17. Sugar (Carbohydrates) • Sugars are carbon molecules with lots of oxygen and hydrogen, so they are also polar molecules • They mix well with water and form many more + - attachments • This is why honey is so sticky!

  18. Starch • Starches are made of many individual sugar rings bonded together • Some starches (white bread, white rice, etc) can be digested quickly • Others (brown rice, whole wheat bread etc) are digested more slowly • This is why brown carbs are better for you!

  19. Lipids (Fats & Oils) • Lipids are made with carbon and hydrogen • Carbon and hydrogen form a nonpolar bond • Since electron sharing is even, no + and – charges form • This means they do not mix with water • Hydrophobic

  20. Consider the Following: • Since oils are not sticky (no polar bonds) they don’t stick to glass like water does • Since oil and water don’t mix, how do you get oil off your hands? • Soap! Soaps are chemicals with hydrophobic and hydrophilic parts so they can make oil and water mix

  21. Nucleic Acids and Amino Acids • DNA and RNA • Stores/handles information • Usually made of a nitrogenous base attached to a sugar with 1 or more phosphate groups • The phosphate groups store energy • Strung together to make proteins • Proteins perform almost all jobs in human body • Messengers • Structural fibers • Enzymes • Transportation • Made using information in DNA

  22. See you next week! • DNA and Proteins will be discussed in week 3

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