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What are the four levels of protein structure?
Primary - the sequence of amino acids
Secondary - how that sequence if folded (a:helix, B: pleated sheet)
Tertiary - how helices or sheets are arranged in three dimensions.
Quaternary - arrangement of 3D structures into whole protein.
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Define Primary Structure
the order in which amino acids are strung together with peptide bonds.
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The primary structure may be twisted or folded into a
Secondary structure
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The Secondary structure of a protein is the
coiling or folding of its polypeptide chains.
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a-helix
"spiral staircase"
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Hair is an a-helical structure formed from the protein
Keratin; Keratin is made up of three a-helices twisted together in a cable.
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Many proteins that span the membrane are made up of
a-helices with the -R groups of hydrophobic (non-polar) amino acids associating with the hydrophobic lipids of the cell membrane and the -R groups of hydrophilic (polar) amino acids forming the pore.
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"B"- pleated sheets
are found in many proteins in nature (such as spider silk) but are less common in human proteins.
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Protein Structure illustrated. Helices, pleated, amino acids that don't have secondary structure.
a-helices are represented as coils
B-pleated sheets are represented as arrow (arrow points amino)
Amino acids that don't have secondary structure are threads
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Tertiary structures within proteins are
formed when separated chains, or different a-helices, or other parts of chains are joind together into a larger, folded structure.
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Types of atomic interactions leading to Tertiary structure
Ionic bonds
Hydrophobic interactions
Van der Waals interactions ("shapes" of molecules fit each other like puzzle pieces)
Disulfide bridges (are formed between cysteines. Cysteine is the only amino acid with an -SH group.Hydrogen bonds
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Heme group
an iron-containing group which holds onto the oxygen molecule.
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Hemoglobin
the oxygen-carrying protein of the blood.
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The proper function of hemoglobin depends critically on
primary, secondary, tertiary and quaternary structure. Any alteration in the protein at any of these levels causes disease
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Primary, secondary and tertiary structure, combine together into a
quaternary structure.
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Chemical reactions either absorb or _________ energy.
Release
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Substance undergoing reaction =
Substrate
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Enzyme names almost always end in
ase
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What splits the disaccharide sucrose into glucose and fructose?
Sucrase
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Graphic module 3 obj. 33
Define enzyme. Demonstrate factors that affect enxyme activeity, including denaturation, and interpret graphs showing the effects of various factors on the rate of enzyme-catalyzed reactions. p.159-164
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What do "squiggles" represent
High energy bonds ATP
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Cellular pathways that require energy are adapted to use
ATP as their energy source
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What is used as the energy currency for the cell?
ATP
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What is the secret of ATP?
High-energy phosphate bonds
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Forms of cellular energy. What are the types of energy?
- Electrical
- Heat
- Potential (chemical)
- Radiant
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What bionergetic event does elctrical produce?
Nerve inpulses
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What bioenergetic event does heat produce?
Cellular chemical reactions
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What bioenergetic event does mechanical produce?
Muscle contractions
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What bioenergetic event does potential (chemical) produce?
Energy-rich covalent bonds
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What bioenergetic event does radiant produce?
photosynthesis in plants
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