Download Basic Chemistry - Ukiah Adult School

Basic Chemistry
Elements
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A substance made up of only one kind of atom
92 naturally occurring
>20 occur in the human body
Standard symbols
H
Fe
O
N
Ca
C
The elements that equal 99% of the human body are
carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur,
and calcium.
Others elements include sodium (Na), potassium (K),
Chlorine (Cl), iron (Fe), copper (Cu), Iodine (I),
magnesium (Mg), and zinc (Zn).
Atoms
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The smallest part of an element
Protons and neutrons in the nucleus
Electrons in the shell
Electrical charge
• Neutron = neutral
• Proton= positive
• Electron= negative
Dalton’s Atomic Theory
1.All matter is composed of extremely small
particles called atoms.
2.All atoms of a given element are identical in size,
mass, and other properties. Atoms of different
elements differ in size, mass, and other
properties.
3.Atoms cannot be subdivided, created, or
destroyed.
4.Atoms of different elements can combine in
simple, whole-number ratios to form compounds.
5.In chemical reactions, atoms are combined,
separated, or rearranged
Compounds
• The union of two different kinds of atoms
• Bonds form between atoms
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Ionic
Covalent
Disulfide
Hydrogen
• Bonds are a force that keep atoms joined
Ionic Bonds
Covalent Bonds
O2
Covalent Bonds
Disulfide bonds
• A covalent bond
• 2 atoms of sulfur within the same larger molecule
Hydrogen Bonds
• Does not involve the donation or sharing of electrons
• Weak bonds
• Responsible for surface tension of water
Chemical Reactions
• Synthesis Reactions
• Bonds are formed
• New compounds created
• Decomposition reactions
• Large molecule is broken into smaller ones
• E.g. digestion
Inorganic compounds of importance –
water, oxygen, carbon dioxide
Water makes up 55% -70% of the human body.
Functions Solvent.
Lubricant.
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Maintain body temperature Changes temperature slowly.
Transportation of nutrients and waste
Essential for chemical reactions
Water compartments – intracellular.
Extracellular: plasma, tissue fluid, lymph.
Water
• Makes up 60 – 75% of the human body
• Functions
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Solvent
Lubricant
Maintain body temperature
Transportation of nutrients and waste
Essential for chemical reactions
Where is the water?
• Intracellular fluid: 65% of body water
• Extracellular fluid: 35% of body water
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Plasma
Lymph
Tissue fluid or interstitial fluid
Specialized fluids
• CSF
• Synovial
• Aqueous humor
Oxygen
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21% of atmospheric gas
Essential for cellular respiration
Cells use oxygen to release ATP for energy
CO2 is produced during cellular respiration
Oxygen is exchanged for carbon dioxide
Cell respiration: Glucose + O2  CO2 + H2O + ATP + heat
Trace Elements
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Needed by the body in small amounts
Obtained in the diet
AKA: minerals
Iron (Fe)
Cobalt
Magnesium (Mg++)
Iodine
Calcium
Phosphorus
Of Acids, Bases and Balance
• Acids
• Substances that increase the hydrogen ion concentration
• Bases
• Substances that decrease the hydrogen ion concentration
• pH
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Parts hydrogen
Values from 0 to 14
The lower the number the higher the H+ ion concentration
7 in neutral
Blood is very slightly alkaline: 7.35- 7.45
Acids, bases, and pH
The pH scale: 0 to 14; pH 7 is neutral.
pH below 7:
pH above 7:
An acid increases the H+ concentration of a solution.
A base decreases the H+ concentration.
Cellular pH: 6.8 to 7.0; blood pH: 7.35 to 7.45.
Buffer systems prevent sudden and drastic changes in the pH of
body fluids.
Buffer systems
• Chemicals or pairs of chemicals that react to minimize change
• H2CO3 (carbonic acid), a weak acid
• NaHCO3 (bicarbonate), a weak base
• Pair present in all body fluids
• Carbonic acid ionizes to become: H+ + HCO3• Bicarbonate ionized to become: Na+ + HCO3• A strong acid (HCl) added to extracellular fluid combines with
Bicarbonate (the weak base) to become: NaCL + H2CO3
• A strong base combine (NaOH) combines with the weak acid
to become: H2O + NaHCO3
• The usual ratio of buffers is 20 bicarbonate: 1 carbonic acid
Organic compounds of importance
All contain carbon and hydrogen covalently bonded; many
contain oxygen, nitrogen, or other elements.
The four major groups:
Carbohydrates
Lipids
Proteins
Nucleic acids
Carbohydrates
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CHO
Serve as sources of energy in cell respiration
Saccharide means sugar
Classified as
• Monosaccharides
• Glucose, fructose, galactose
• Pentose not involved in energy but structural components of RNA
• Disaccharides
• Sucrose= glucose + fructose
• Lactose = glucose + galactose
• Maltose = glucose + glucose
• Oligosaccharides
• Chains of 3 -20 Monosaccharides
• Indigestible
• On outer surfaces of cell membranes
• Polysaccharides
• Composed of thousands of glucose molecules
Carbohydrates cont’d
• Glycogen
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Highly branched chain of glucose
Synthesized in the liver
Storage form of glucose
Stored primarily in the liver and in small amounts in skeletal
muscle
• Cellulose
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Straight chains of glucose molecules
Produced by plants as part of their cell walls
Humans do not have the enzymes to digest them
“Fiber”
Exercises the gut
Prevent constipation
Lipids (see Table 2–4)
True fats – fatty acids and glycerol.
Triglycerides – stored energy.
Phospholipids – diglyceride + phosphate.
Part of cell membranes.
Steroids – based on cholesterol.
Vitamin D, steroid hormones.
Lipids
• Neutral or true fats
• Glycerol and 1, 2, or 3 fatty acid molecules
• 3 fatty acids = triglyceride
• 2 fatty acids = diglyceride
• 1 fatty acid = monoglyceride
• Saturated vs. unsaturated
Other fats
• Phospholipids
• Diglycerides with a phosphate group
• Structural components of cells
• E.g.: myelin, parts of cell membranes
• Steroids
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Cholesterol
4 rings of carbon and hydrogen
Synthesized in the liver
Significant component of cell membranes
Precursor of steroid: estrogen, testosterone and of vitamin D
Proteins – made of amino acids
(General functions: see Table 2–5)
Primary structure – sequence of amino acids.
Secondary structure – simple folding.
Tertiary structure – more complex folding.
Quaternary structure – two or more amino acid chains.
Excess amino acids in the diet can be converted to simple
carbohydrates.
Proteins
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Built of smaller units called amino acids
20 amino acids
8 are essential
Sequence of amino acids is specific for each type of protein
Building blocks for tissues,
Enzymes
Nucleic acids – DNA and RNA
Made of subunits called nucleotides.
Nucleotide – a pentose sugar: deoxyribose or ribose.
a phosphate group.
a nitrogenous base: adenine, guanine,
thymine, cytosine, and uracil.
DNA is a double helix.
RNA is a single strand.
DNA and RNA
• Large molecules
• Consist of smaller subunit
• nucleotides
Nucleic acids (continued; see Table 2–6)
DNA is found in chromosomes.
Function:
RNA functions in the process of protein synthesis.
ATP – adenosine triphosphate; an energy transfer
molecule.
Enzymes
• Catalysts: speed up chemical reactions
• Specific to the reaction needed
• Shape determines function
Wrap-Up Question
Give the proper term for each brief description.
1. A bond-forming reaction
2. The water within cells
3. A pH of 7.4
4. Energy production within cells
5. Energy storage form in the liver
6. Proteins that catalyze reactions
7. The lipids of cell membranes
8. An energy transfer molecule
Most of the body’s fluid is contained
__________
• 2. Define:
• A covalent bond
• An ionic bond
• A hydrogen bond
• A disulfide bond
• 1.