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Chemistry, Matter, & Life
Elements
 Approximately 116 known elements
 Only 21 are needed by living things
Oxygen
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Most abundant element in humans
65% of body mass
Needed for metabolism
Component of water
Found in most organic substances
Carbon
 18.5% of human body mass
 Component of all organic compounds
Hydrogen
 9.5% of human body mass
 Present in most organic compounds
 Component of water
Other Essential Elements
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Calcium
Phosphorus
Potassium
Sulfur
Sodium
Chlorine
Magnesium
Trace Elements
 Manganese, iron, cobalt, zinc, iodine, molybdenum
 Used for such things as: metabolism, hormones,
bones, hemoglobin, enzymes
 Table 2-1
Atom Structure
Ionic Bonds
Important Ions
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Sodium
Potassium
Bicarbonate
Table 2-2
Electrolytes
 Ions that appear when substances dissociate in
solution
 Important in maintaining homeostasis
 Generate electrical currents that can be detected and
recorded
 Electrocardiogram (EKG)
 Electroencephalogram (EEG)
Covalent Bonds
Acids, Bases, & pH Scale
pH Fluctuations
 Normal pH is 7.35-7.45
 Alkalosis – too basic (7.5-7.8)
 Acidosis – too acidic (7.0-7.3)
Acidosis
 Respiratory acidosis
 Too much carbon dioxide is present
 Chest deformities/injuries
 Lung disease/injury
 Metabolic acidosis
 Too much acid is produced or the kidneys cannot
remove enough
 Diabetes
 Severe diarrhea
 Alcohol, cancer, vigorous exercise, liver disease
Alkalosis
 Respiratory alkalosis
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Low carbon dioxide levels
High altitude
Lung disease
Lack of oxygen
Salicylate poisoning
 Metabolic alkalosis
 Prolonged vomiting
 Certain medications
Buffer
 Solution that resists change in pH regardless of the
acid or base added
 Buffer solutions consist of a weak acid and a salt of
that weak acid
 Used to maintain homeostasis
Carbonic Acid Buffering System
 When acid is added:
HCl + NaHCO3  H2CO3 + NaCl
acid
buffer salt
weak acid
salt
 When base is added:
NaOH + H2CO3  NaHCO3 + H2O
base
buffer acid
buffer salt
water
Biomolecules
 Organic compounds are those that contain carbon
(with a few exceptions)
 Four major categories of biomolecules:
 Carbohydrates
 Lipids
 Proteins
 Nucleic acids
Carbohydrates
 Composed of carbon, hydrogen, and oxygen
 Ratio of hydrogen to oxygen is 2:1
 Used for:
 ENERGY
 Structure of cell components, including cell membranes
 Reserve supply of energy
Monosaccharides
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Simple sugar
Glucose
Galactose
Fructose
Deoxyribose
Ribose
Dissaccharides
 Double sugar
 Two monosaccharides are joined
 Created through process of dehydration synthesis
(condensation); one molecule of water is lost
 Sucrose
 Maltose
 Lactose
Dehydration Synthesis
 The reverse of this reaction is hydrolysis
Polysaccharides
 Long chains of monosaccharides linked together
 Starch
 Cellulose
 Glycogen
Lipids
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Composed of carbon, hydrogen, and oxygen
Has many more hydrogen than oxygen
Ex] CH3(CH2)24CO2-(CH2)29CH3
Divided into: fats (triglycerides), phospholipids, and
steroids
Fats (Triglycerides)
 Used as energy source and energy storage
 Provide protection, padding, and insulation
 Created by combining three fatty acid groups with
one glycerol molecule through dehydration synthesis
Saturated vs. Unsaturated Fats
 Saturated fats
 Mostly animal fats
 Solid at room temperature
 Unsaturated fats
 Vegetable oils
 Liquid at room temperature
Saturated vs. Unsaturated Fatty
Acids
Phospholipids
 Composed of glycerol and fatty acids, but also contain
a phosphate group
 Component of cell membranes
 Abundant in nerve and muscle cells
Steroids
 Similar in composition to lipids, but structurally
composed of interconnected carbon rings
 Most common steroid is cholesterol
 Used to create sex hormones, hormones from the
adrenal cortex, and vitamin D
 Found in large amounts in nerve tissue
 Component of gallstones
Cholesterol
Proteins
 Composed of carbon, hydrogen, oxygen, and
nitrogen
 Most also contain sulfur
 Some have phosphorus
 Building blocks are amino acids
Amino Acids
 There are 20 amino acids that are known to be used
to create proteins
 Humans can only make 10 of those
 The other 10 must be taken in through diet
 essential
Structure of AminoAcids
 -COOH is a carboxyl group
 -NH2 is an amino group
 -R represents differences
in base molecule of each
amino acid
Function of Proteins
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Structural component of cells and tissues
Antibodies
Muscle contraction
Identification markers for cells
Energy source
Transport oxygen
Enzymes
Enzymes
 Modified proteins that lower activation energy
required to start a reaction
 Enzymes only work on specific substrates
 Never consumed or changed in a reaction
 Often recognized by the –ase ending
Lock & Key Model
Factors That Affect Enzymes
 Enzymes are a type of protein
 Denatured by:
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Heat
Radiation
Electricity
pH values
Certain chemicals
Diseases of Enzyme Deficiency
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Tay Sachs
Phenylketonuria
Lactose intolerance
Gaucher’s
Fabry’s
Nucleic Acids
 Composed of carbon, hydrogen, oxygen, nitrogen,
and phosphorus
 Building blocks are nucleotides
 Nucleotides join through the process of dehydration
synthesis to create larger molecules
 Two types of nucleic acids:
 Deoxyribonucleic acid (DNA)
 Ribonucleic acid (RNA)
DNA
 Composed of
deoxyribose and the
bases thymine, guanine,
cytosine, and adenine
 Serves as genetic material
for cell
RNA
 Composed of ribose and
the bases adenine,
guanine, cytosine, and
uracil
 Assists with protein
synthesis
Adenosine Triphosphate
 Molecule used in all living things to store and provide
energy