Water, pH, and

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• Water, pH, and
• Biological Molecules

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• I. The Importance of Water to Life (Sections 3.1
  and 3.2)
• 71 of Earths surface
• 66 of weight of human body

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• B. Important properties of water
• 1. Required/generated by many cellular reactions
  (breaking down food)
• 2. Important solventhydrogen bonds with polar or
  charged molecules (NaCl) Figure 3.1
• Solid versus liquid
• densities,importance for
• marine organisms
• 4. Important for insulating Earth, and for
  cooling living organisms by sweating
• 5. Cohesion and surface tension allows water to
  move up a tree in cells allows insects to walk
  on water.
• 6. Hydrophobic versus hydrophilic molecules
  control certain cellular activities

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• C. Acids and Bases
• 1. Common acids (vinegar) and common bases (lye,
  ammonia)
• 2. Definition of an acidsubstance that yields
  hydrogen ions in solution (HCl) Figure 3.5
• 3. Definition of a basesubstance that accepts
  hydrogen ions (NaOH) Figure 3.5

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• C. Acids and Bases
• 4. pH scale (lower pH more acidic raise pH
  less acidic, more basic, or alkaline) Figure 3.6
• 5. pH and health diabetes, cardiac arrest,
  vomiting as result of acidosis
• 6. pH and the environmentacid rain (Interactive
  Activity 1)
• 7. Normal pH and buffering body keeps a balance
  so that pH is relatively constant at different
  parts of the body if it changes, the body will
  try to correct it by buffering the solution (ex
  stomach pH 2, small intestine pH 6 both
  acidic, but buffers neutralize acid from stomach
  when materials move to small intestine.

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• II. Carbon Is a Central Element in Life (Section
  3.3)
• A. Carbon is starting point for biological
  molecules
• 1. Four electrons in outer shell can make four
  bonds (covalent, stable)
• 2. Ball-and-stick models demonstrating covalent
  bonds CH4 (methane)
• 3. Isomers
• 4. Double bonds
• 5. Rings

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• The Molecules of Life Carbohydrates. Lipids,
  Proteins, and Nucleic Acids (A. A. Carbohydrates

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1. Monomerrings of C, H, and O (glucose,
C6H12O6) called monosaccharides a) Examples
glucose, fructose, galactose, ribose, deoxyribose
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• 2. Polymers are chains of monomers created by
  chemical reaction called condensation (also
  called dehydration synthesis)
• a) Simplest polymer is disaccharide examples
  sucrose, lactose, maltose
• 3. Condensation reactions can be reversed
  hydrolysis (digestion in our guts -Interactive
  Activity 2)

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• 4. Simple sugars on food labels are mono and
  disaccharides Figure 3.11 (Interactive Activity
  3 or 4)
• 5. Complex carbohydrates on food labels long
  chains of monomers called polysaccharides Figure
  3.12
• a) Starch, main form of energy storage

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• b) Glycogen, primary short-term energy storage in
  animals, released as glucose into the bloodstream
  when needed.

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• c) Cellulose, functions to provide structure to
  plants indigestible to mammals (fiber on food
  label) (Interactive Activity 4)
• d) Chitin, functions in external skeleton of
  arthropods

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• B. Lipids
• 1. Common characteristics of lipids composed of
  C, H, and O, but insoluble in water.
• 2. Major function Energy storage and insulation,
  but also function as hormones and the outer
  lining of all cells.

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• 3. Glyceridescomposed of glycerol and fatty
  acids (For example, triglycerides UA 3.10 and
  Figure 3.13).
• a) Make up 90 percent of lipid in food

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b) Difference between saturated and unsaturated
fatty acids
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• c) Saturated fatty acids and health
• d) Main semi-permanent energy stores in animals
  Figure 3.15. Why not use carbohydrates like
  plants? (Interactive Activity 4, 5 6)

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• 4. Steroids
• a) Composition Figure 3.16
• b) Function Figure 3.17 (Interactive Activity 7
  8)

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• Phospholipids
• a) Composition Figure 3.18a
• b) Function Figure 3.18b. Under the resources
  for Chapter 3, there is a nice animation showing
  the behavior of phospholipids in water and oil
  file named figure 3_20.

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• C. Proteins
• 1. Huge range of functions Table 3.2
• 2. Composition monomers amino acids
• a) Similarities of amino acids Figure 3.19a

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• b) Differences Figure 3.19b (Interactive
  Activity 9)
• Polymers polypeptides

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• 4. Linkage by condensation this is nicely
  animated in the resources for Chapter 3, file
  named figure 3_22 -Interactive Activity 4.
• 5. Shape and function

• 6. Four levels of protein structure Figure 3.22
• Primaryunique to every
• type of protein

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• b) Secondaryhydrogen bonds
• in alpha helix and beta pleated
• sheet
• c) Tertiary
• d) Quaternary

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• 7. Denatured proteins (albumin in egg whites)
• 8. Lipoproteins and glycoproteins

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D. Nucleic Acids 1. Functionprovides information
for structure of proteins 2. Compositionnucleotid
es Figure 3.24a (ATP)
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• DNA deoxyribonucleic acid
• In nucleus
• Controls cell activities
• Directs production of proteins
• Makes up genes on chromosomes
• Controls heredity

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• RNA ribonucleic acid
• Helps DNA make proteins
• Found all around the cell