Chapter 5 Flashcards
Neutron
live in nucleus, neutral charge
Electron
live in space surrounding nucleus, very small and very fast moving
Matter
any material that takes up space. Consists of one or more elements
Element
substance that cannot be broken down by chemical means into other substances.
Compound
substance consisting of two or more different elements in a fixed ratio, more common than pure elements, NaCl is an example
Trace elements
essential but are only needed in minute quantities
name all elements of the required for the human host that are not trace elements
Oxygen O, Carbon C, Hydrogen H, Nitrogen N (96.3% of body weight) Calcium Ca, Phosphorus P, Potassium K, Sulfur S, Sodium Na, Chlorine Cl, Magnesium Mg (3.7% of body weight)
trace elements
Boron B, Chromium Cr, Cobalt Co, Copper Cu, Fluorine Fl, Iodine I, Iron Fe, Manganese Mn, Molybdenum Mo, Selenium Se, Silicon Si, Tin Sn, Vanadium V, Zinc Zn
three benefit/problems that the human host can experience when their diet does not include does not meet the minimum amount of trace elements
- Without iron, your body can’t transport oxygen, leading to anemia
- Iodine deficiency prevents production of thyroid hormones, resulting in goiter
- Fluoride is usually added to municipal water and dental products to help reduce tooth decay
Why water is important for every living organism
Life evolved in water
All living organisms need water
Cells consist of about 75% water
4 properties of the water molecule due to its polarity
- surface tension
- high boiling point (specific heat)
- Low ice density (insulation)
- Ion formation (solvent)
- (Acid base properties)
Surface tension
hydrogen bonds that hold water molecules together give water unique properties. Water is cohesive and adhesive. Cohesion: tendency of water molecules to stick to one another. Adhesion: tendency to form hydrogen bonds with substances other than water. Plants depend on cohesion to help transport water and nutrients from their roots to their leaves.
High boiling point (specific heat)
heat must be absorbed to break hydrogen bonds. Heat is released when hydrogen bonds form. To raise the temperature of water, hydrogen bonds between water molecules must be broken before the molecules can move faster. When warming up, water absorbs a large amount of heat and when water cools, water molecules slow down, more hydrogen bonds form, and a considerable amount of heat is released. Earth’s giant water supply moderates temperatures, helping to keep temperatures within limits that permit life. Water’s resistance to temperature change also stabilizes ocean temperatures, creating a favorable environment for marine life
Low ice density (insulation)
water can exist as a gas, liquid, or solid. Its less dense as a solid than a liquid because of hydrogen bonding. When water freezes, each molecule forms a stable hydrogen bond with its neighbors. As ice crystals form, the molecules are less densely packed than in liquid water. Because ice is less dense than water, it floats. Water expands when it freezes. Aquatic life survives the winter due to insulation from layer of ice.
Ion formation (solvent)
water dissolves hydrophilic solutes (polar solutes and ions). Water does not dissolve hydrophobic solutes (nonpolar molecules, such as fats).
- Solution: liquid consisting of a mixture of two or more substances
- Solvent: dissolving agent
- Aqueous solution: one in which water is the solvent
