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Chemistry
the branch of science concerned with the composition and properties of material substances, including their abilities to change into other substances
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Matter
Anything that takes up space and has mass. All forms are made up of atoms
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Atom
units of matter that cannot be broken down into simpler substances by ordinary chemical means
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Element
a "pure" form of matter containing only one kind of atom
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Isotope
atoms that have the same number of protons but differ in the number of neutrons
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Radioisotope
unstable, radiation-emitting isotopes
about 60 occur naturally
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Compound
molecule that contains 2 or more different elements
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Covalent Bond
a chemical bond formed when outer shell electrons are shared between atoms
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Molecule
a chemical structure composed of atoms held together by covalent bonds
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Ion
an atom or group of atoms that carries an electric charge resulting from the loss or gain of electrons
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Ionic Bond
a chemical bond that results from the mutual attraction of oppositely charged ions
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Hydrogen Bond
a weak chemical bond formed between a partially positively charged hydrogen atom in a molecule and a partially negatively charged atom in another molecule or in another region of the same molecle
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Acid
any substance that inreases the concentration of hydrogen ions in solution
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Base
any substance that reduces the concentration of hydrogen ions in solution
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pH
a measure of hydrogen ion concentration of a solution; values range from 1-14
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pH Scale
a scale for measuring the concentration of hydrogen ions.
Ranges from 0-14
- pH of 7 is neutral
- pH <7 is acidic
- pH >7 is basic
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Buffer
a substance that prevents dramatic changes in pH by removing excess hydrogen ions from solution when concentrations increase and adding hydrogen ions when concentrations decrease.
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Macromolecule
a giant molecule of life such as a nucleic acid, protein, or polysacchride. formed by the joining together of smaller molecules
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Polymer
a large molecule formed by the joining together of many smaller molecules of the same general type (monomers)
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Monomer
a small molecule that joins with identical molecules to form a polymer
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Dehydration Synthesis
the process by which polymers are formed. Monomers are linked together through the removal of a water molecule
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Hydrolysis
the process by which polymers are broken apart by the addition of water
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Carbohydrate
an organic molecule that provides fuel for the human body (sugars and starches). can be classified by size into the monosaccharides, disaccharides, and polysaccharides
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Monosaccharide
the smallest molecular unit of a carbohydrate.
known as simple sugars
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Oligosaccharide
a chain of a few monosaccharides (simple sugars) that are joined together by dehydration synthesis.
Disaccharides, formed by the joining of 2 monosaccharides, are an example
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Disaccharide
a molecule formed when 2 monosaccharides covalently bond to each other through dehydration synthesis.
Known as a double sugar
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Polysaccharide
a complex carbohydrate formed when large numbers of monosaccharides (most commonly Glucose) join together to form a long chain through dehydration synthesis.
Most store energy or provide structure
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Starch
the storage polysaccharide in plants
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Glycogen
the storage polysaccharide of animals
this complex carbohydrate is stored in the liver and muscles where it serves as a short-term energy source that can be broken down to release energy-packed glucose molecules
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Cellulose
a structural polysaccharide found in plants.
humans lack the enzymes to break this down, and thus it passes unchanged through our digestive tract.
has no nutritional value as a nutrient, however is an important form of dietary fiber
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Lipid
a compound (i.e. triglyceride, phospholipid, steroid) that doesn't dissolve in water.
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Triglyceride
the lipids composed of one molecule of glycerol and 3 fatty acids.
known as fats when solid and oils when liquid
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Fatty Acid
chains of carbon atoms bonded to hydrogens with an acidic group (COOH) at one end.
3 bond to a molecule of glycerol to form a triglyceride (fat)
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Phospholipid
an important component of cell membranes.
it has a nonpolar "water-fearing" tail (made up of fatty acids) and a polar "water-loving" head (containing an R group, glycerol, and phosphate)
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Hydrophobic
water-fearing
[i.e. the tails of phospholipids (components of the plasma membrane)]
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Hydrphilic
water-loving
[i.e. the heads of phospholipids (components of the plasma membrane)]
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Steroid
a lipid, such as cholesterol, consisting of 4 carbon rings with functional groups attatched
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Protein
the macromolecules composed of amino acids linked by peptide bonds.
functions include structural support, transport, movement, and reguation of chemical reactions
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Amino Acid
the bulding blocks of proteins consisting of a central carbon atom bound to a hydrogen atom, an amino group (NH2), a carboxyl group (COOH), and a side chain designated by the letter R.
20 are important to human life
some can be synthesized by our bodies (nonessential), where as others cannot be synthesized & must be obtained through food we eat (essential)
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Peptide
a chain containing only a few amino acids
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Polypeptide
a chain containing 10 or more amino acids
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Primary Structure
the precise sequence of amino acids of a protein. this sequence, determined by the genes, dictates a protein's structure and function
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Secondary Structure
the bending and folding of the chain of amino acids of a protein to produce shapes (i.e. coils, spirals, and pleated sheets). these shapes form as a result of hydrogen bonding between different parts of the polypeptide chain.
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Tertiary Structure
the 3-dimensional shape of proteins formed by hydrogen, ionic, and covalent bonds between different side chains
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Denaturation
the process by which changes in the environment of a protein, such as increased heat or changes in pH, cause it to unravel and lose its 3-dimentional shape. change in the shape of a protein results in loss of function
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Quaternary Structure
the shape of an aggregate protein.
determined by the mutually attractive forces between the protein's subunits
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Enzyme
a substance (usually a protein, but sometimes an RNA molecule) that speeds up chemical reactions without being consumed in the process
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Active Site
a specific locattion on an enzyme where the substrate binds
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Enzyme - Substrate Complex
complex formed when a substrate binds to an enzyme at the active site
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Deoxyribonucleic Acid (DNA)
the molecular basis of genetic inheritance in all cells and some viruses.
a category of nucleic acids that usualy consists of a double helix and two strands. the sequence of nucleotides carries the instructions for assembling proteins
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Ribonucleic Acid (RNA)
a single-stranded nucleic acid that contains ribose (a 5-carbon sugar), phosphate, adenine, uracil, cytosine, or guanine.
plays a variety of roles in protein synthesis
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Nucleotide
a subunit of DNA composed of one 5-carbon sugar (either ribose or deoxyribose), one phosphate group, and one of the 5 nitrogen-containing bases.
building blocks of of nucleic acids (DNA/RNA)
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Adenosine Triphosphate (ATP)
a nucleotide that consists of the sugar ribose, the base adenine, and 3 phosphate groups.
the energy currency of all living cells
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Atomic Number
the number of protons in an atom's nucleus
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Atomic Weight
sum of the number of protons plus the number of neutrons in an atom
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Radiation
energy moving through space (i.e. radio waves, light, heat, and the excess energy/particles given off by unstable isotopes as they break down)
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