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atoms, elements, molecules, compounds Basic Chemistry …. But this is Biology?????
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Trace elements? What are the most common elements in ALL living things
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Symptom of an iodine deficiency Iron deficiency? Fluorine deficiency?
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Locations and charges of protons? Neutrons? Electrons? Structure of an atom (its subatomic particles)
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Atomic number Atomic mass
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Atomic Mass vs. Atomic Number?????
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What is an isotope?
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Cancerous throat tissue Isotopes use to diagnose disease Give a molecule similar to glucose that has a radioactive tag PET scan picks up the released radiation and detects areas of high metabolism
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Radioactive iodine High doses can treat thyroid cancer Small doses used to test thyroid function.
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shows the concentration of radioactive tracer bound to monoamine oxidase B (MAO B). Red shows the highest concentration. MAO B is important because it breaks down the chemicals that allow nerve cells to communicate and regulate blood pressure.
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What causes an atom to react with other atom? Or… would cause it to be nonreactive (stable)?
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Ionic Bond
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(–) O HH (+)
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Hydrogen bond
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Strong attraction for electrons
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Cohesion of water → water sticking to itself Does this because of hydrogen bonding Results in water having surface tension –“film” on top of water
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Transpiration Uses cohesion and adhesion to move water from the roots to top of a tree
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Adhesion of water To cells of xylem Cohesion of water to itself
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Adhesion → water sticking to something else Meniscus
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Temperature moderation Water resists changes in temperature Water can absorb and release a lot of thermal energy with a small change in temperature ex: lake temperatures
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Feb: 15.7° F July: 70.4 ° F Feb: 44.3° F July: 65.3 ° F moderate temperatures at coasts
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ex: evaporative cooling -when water evaporates from our skin, it takes a lot of thermal energy with it
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Density Water is densest at 4° C Ice is less dense than liquid water Provides insulation and allows wildlife to survive under a layer of ice Ice floats
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Water is an almost universal solvent Ionic compounds (like salt) will dissolve in water Polar molecules will dissolve in water (sugar) In a solution the SOLVENT is the substance in a greater amount The SOLUTE is the substance present in a lesser amount
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Glucose
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A few water molecules can break apart into ions –hydrogen ions (H + ) –hydroxide ions (OH – ) Copyright © 2009 Pearson Education, Inc. pH
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Acids vs. bases –An acid is anything that INCREASES the relative concentration of H+ –A base is anything that DECREASES the relative concentration of H+ Either by adding OH- or removing H+ Copyright © 2009 Pearson Education, Inc. pH
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A pH scale (pH = potential of hydrogen) is used to describe whether a solution is acidic or basic –pH ranges from 0 (most acidic) to 14 (most basic) –A solution that is neither acidic or basic is neutral (pH = 7) Copyright © 2009 Pearson Education, Inc.
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Acidic solution pH scale Battery acid 0 1 2 3 4 5 Lemon juice, gastric juice Grapefruit juice, soft drink, vinegar, beer Tomato juice Rain water Human urine Saliva Pure water 6 7 Human blood, tears Seawater 8 9 10 11 12 13 Milk of magnesia Household ammonia Household bleach Oven cleaner Neutral solution Basic solution NEUTRAL [H + ]=OH – ] Increasingly ACIDIC (Higher concentration of H + ) 14 Increasingly BASIC (Lower concentration of H + ) Logarithmic scale Change in one unit on pH scale = 10 x change in hydrogen ion concentration
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Solution A has a pH = 4 Solution B has a pH = 2 How much more acidic is Solution B? Solution C has a pH = 9 Solution D has a pH = 12 How much more H+ ions does solution C have compared to solution D?
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Why is pH important? Different areas of the body have different pH values –Ex: stomach blood If the pH varies from this value, proteins lose their shape and don’t work
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Molecules that can accept or release H+→ resist change in pH Are usually weak acid/base pairs
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