BIOl 213 1st Edition Lecture 2 Outline of Last Lecture I. Class introductionA. ExamsB. GradingII. Cell and Molecular Biology main pointsIII.The Cell TheoryA.Every living cell comes from another living cellIV. Pasteur Experiment A. Set up/experimentB. Results of experimentC. Explanation of resultsD. What if Pasteur were wrong?Outline of Current Lecture I. Review of Pasteurization vs sterilizationII. DNA replicationA. Common goal of cellsB. Compartmentalization in cells III. The AtomA. Bonds – covalent and ionicIV. WaterA. Properties B. What if these properties weren’t true?V. Weaker bondsA. Hydrogen bondsB. Hydrophobic interactionsC. Van der Waals interactionsVI. pHVII. The MoleCurrent LectureI. Review of pasteurization vs sterilizationa. Pasteurization: kills some thingsi. Enough so that it’s not dangerous to eatii. Ex: milkb. Sterilization: kills everythingThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.c. Pasteur actually used sterilization in his experiment, not pasteurizationII. DNA replicationa. The common goal of all cells is DNA replicationi. Just like the common goal of all living things is to reproduceii. DNA is the blueprint for everything in the cellb. Every molecule and process in the cell contributes something to this goali. Especially proteins! Some examples:1. Transcription2. Transporters3. DNA repairc. The cell compartmentalizes to save energy i. It would cost too much energy to just have everything floating aroundii. Mitochondria1. The cells energy sourceiii. Cellular membrane: to regulate what comes in and what goes out1. What goes in and what goes out is usually determined by whetheror not it will contribute to DNA replication2. The cell especially wants to keep energy in3. There is transportation viaa. Diffusionb. Mediated transportation (of things that can’t diffuse)iv. Nucleus1. Contains the DNAv. Cytoskeleton1. Things are moved throughout the cell via the cytoskeletond. Prokaryotes compartmentalize tooi. Even though prokaryotes don’t have membrane-bound organelles, they still have specific metabolic pathways in confined areas of the celle. Whenever a process doesn’t work correctly, that means the cell has some kind ofdiseaseIII. The Atoma. Positively charged nucleus composed of positive protons and neutral neutronsb. A negatively charged electron cloudi. Electrons store and carry energyii. Seen in redox reactions – this is how energy is moved in biologyc. Atomic number = number of protons i. determines the elementii. number protons usually = number electronsd. Atomic weight = number of protons + neutronse. Bonds – made of electronsi. Covalent1. When two atoms share electrons2. Energy in biology is stored in covalent bondsa. Example: the breaking down of glucose (breaking covalent bonds) results in the creation of ATP (energy)3. Can be polar or nonpolar, depending on the electronegativity of the atomsii. Ionic1. When two atoms transfer electrons2. Results in ions when the bond is brokeniii. Covalent bonds are the strongest in biology because the cell is an aqueous environment. Ionic bonds are very weak in aqueous solutions due to the polarity of waterIV. Watera. Is a nonpolar molecule withb. Polar covalent bondsi. The oxygen is more electronegative then the hydrogen 1. Oxygen has a partial negative charge2. The hydrogens have a partial positive chargeii. This is why ionic (and polar) molecules dissolve in water1. The water molecules are attracted to the positive or negative charges of the ions (ex: NaCl dissolves in water)2. The cation (Na+) gets surrounded by the partially negative oxygens3. The anion (Cl-) gets surrounded the partially positive hydrogens 4. Saturationa. This is when the attractions between the water molecule and ionic molecule aren’t strong enough to result in the dissolving of the ionic moleculeb. Essentially, all of the water molecules are already attractedto an ionc. It is more stable for the cation and anion to stay togetherd. However, saturation is never seen in a cellc. Hydrogen bondsi. Electrostatic interaction between a H in a polar covalent bond an another atom, usually an O or a N, in a polar covalent bondii. This is what holds multiple water molecules togetheriii. These are the reason for many of waters’ unique propertiesd. Unique properties i. High boiling point1. Due to hydrogen bonds2. It takes a lot of energy to break the hydrogen bonds to allow the water to become gaseousii. High specific heat1. Due to hydrogen bonds2. Water can take in a lot of energy before increasing in temperatureiii. Liquid at room temperatureiv. Lower density as solid (ice floats)1. When water is solid, most of the water molecules are held together by hydrogen bonds2. This results in a unique crystalline structure a. That has more space in between the water molecules than when water is liquidv. High surface tension1. Due to hydrogen bonds2. This can be seen when water droplets form spheres instead of spreading oute. What if the unique properties of water weren’t true?i. Low specific heat1. Temperatures wouldn’t be as regulated because the large bodies of water wouldn’t be able to take in or release as much energy/heatii. Low boiling point1. Sweating wouldn’t work because the water would evaporate before it would be useful2. There would be no surface water on the skin3. There would be no blood because it would evaporate at high bodytemperaturesiii. Not liquid at room temperature1. We wouldn’t be able to drink itiv. Higher density as solid1. Aquatic life couldn’t live in frozen bodies of water because the ice would sink, causing all of the water to eventually freeze from the bottom upa. Floating ice insulates the water below2. There would be no glaciers  the oceans would be fully frozen3. We would still be in an ice age because the oceans would be frozenv. Low surface tension1. Plants wouldn’t be able to transport water because capillary action wouldn’t worka. Capillary action is how water is transported up the “tubes” in plants due to adhesion (water sticks to other things) andcohesion (water sticks to itself through surface tension)2. No photosynthesis, which also relies on capillary action to transport the water to the leafa. Remember why water is needed in photosynthesis: When an electron from the chlorophyll pigment of photosystem IIis excited by the sunlight, it is transported through the