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Objectives
1.
2.
3.
Distinguish organic from inorganic
compounds
Explain the importance of water to the
body
Differentiate a salt, an acid and a base
Biochemistry
Chapter 2
Bell Ringer: What is the major function of
potassium in the body?
Overview
A. Inorganic compounds
 All
 Lack
molecules in the body are either
inorganic or organic
carbon
simple molecules
 Small,

Examples: water, salts and acids and bases
1. Water
2. Salts
 2/3
 Ionic
the body’s weight
 Properties:




High heat capacity- prevents sudden body
temp changes
Polarity/solvent properties- helps chemical
reactions occur, dissolves nutrients, wastes
and lubricates
Chemical reactivity- major reactant
Cushioning- fluids that protect the body
compounds
in water
 Ca and P salts most abundant
 Are all electrolytes (conduct electrical
current in solution)
 Dissociate
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3. Acids
4. Bases
 Also
 Also
 Substance
 Substances
electrolytes
that can release hydrogen
ions, H+ (proton donors) and anions

Examples: HCl, acetic acid, carbonic acid
electrolytes
that can release hydroxyl
ions, OH- (proton acceptors) and cations

Example: bicarbonate (HCO3-)
Neutralization reaction- acids and bases
react to form salt and water
Objectives
Importance of pH
4. Explain the importance of pH to the body
5. Define carbohydrates in terms of their
building blocks, structures and functions in
the body
 pH
of 7 is neutral (hydrogen ions =
hydroxyl ions)
 pH below 7 is acidic (> hydrogen ions)
 pH above 7 is basic (> hydroxyl ions)
Bell ringer: List 4 important roles of water in
the body and provide an example of each.
pH of the blood
B. Organic compounds
 Narrow
 Carbon
 If
 Large

range (7.35 to 7.45)
pH is not stable death can occur
Example: if blood becomes slightly acidic
hemoglobin cannot carry oxygen
 Regulated
by kidneys, lungs and buffers
(weak acids and bases that take up
excess ions)
containing compounds
covalently bonded molecules
 Carbohydrates, lipids, proteins and
nucleic acids
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1. Carbohydrates
Functions
 Sugars
 Source
and starches
C, H and O
 Ratio- 2H to 1O
 Classified according to size
(monosaccharides, disaccharides or
polysaccharides
 Building block: monosaccharides
 Contain
of food energy for cells (ATP from
oxidation of glucose)
 Excess converted to glycogen or fat and
stored
 Used for cell structure
 Found in genes (ribose, deoxyribose)
 Guide cellular interactions
Structure
 Monosaccharides
(simple sugars)
to 7 carbon atoms (single ring)
 Glucose, fructose, galactose
 Ribose and deoxyribose
3
Disaccharides
Disaccharides in the diet
 Two
 Sucrose
simple sugars joined by a synthesis
reaction
 Dehydration reaction (a type of
condensation reaction) – water molecule
lost as the bond forms
 Bond between sugars is a glycosidic
linkage
 Hydrolysis- bond is broken when water
molecule is added
( glucose + fructose)- cane sugar
(glucose + galactose)- milk
 Maltose (glucose + glucose) – malt
 Lactose
 These
must be broken down to be
absorbed by the blood
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Polysaccharides
Objective
 Long,
branching chains of simple sugars
insoluble, not sweet
 Used for storage
 Starch (plants)- grains and root
vegetables
 Glycogen (animals)- muscle and liver
6. Define lipids in terms of their building
blocks, structures and functions in the body
2. Lipids
Triglycerides
 Large
 Function:
 Large,
molecules, insoluble in water
C, H and O but many H atoms
compared to O
 Triglycerides, phospholipids and steroids
 Found in meat fat, eggs, milk products
and oils
 Contain
Bell Ringer: What molecule in animals is a
major storage of carbohydrates?
concentrated source of usable
energy
 Stored in fat deposits beneath skin and
around organs
 Protect from heat loss and “bumps”
 Termed “neutral fats”
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Structure
Types
 Building
 Saturated
blocks: glycerol + 3 fatty acids
depends on length of fatty acid
chains and types of bonds between
carbons
 Solidity
– single covalent bonds
between carbons (solid)

Animal fats, tend to have long chains
 Unsaturated-
double or triple bonds
between carbons (oils)

Plant oils, shorter chains
 Trans
fats- oils that have been solidified by
adding H atoms
• Still formed by dehydration reaction and
broken by hydrolysis
• Bond formed is an ester bond
A monounsaturated triglyceride
Phospholipids
 Similar
to triglycerides
phosphorus containing group takes the
place of one of the fatty acid chains
 Makes a polar head (slightly charged)and
a tail
 Phosphorus “head” interacts with water
(hydrophilic) and ions but fatty acid “tail”
does not (hydrophobic)
 Found in cell membranes
A
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Steroids





Flat molecules, 4
interlocking rings
Fat-soluble
Cholesterol most
important
Found in cell
membranes and
needed to make
Vitamin D, steroid
hormones and bile salts
Some made in liver and
ingested from animal
products
Review questions
 What
are the three basic
monosaccharides?
 What type of lipid contains three fatty
acid chains and a glycerol?
 What is the most common steroid?
 What are the fat soluble vitamins?
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