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37 Cards in this Set
- Front
- Back
what do enzymes regulate?
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biological reactions such as digestion and cellular metabolism
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what 2 functional groups do amino acids contain?
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amino group (NH2)
carboxylic acid group (COOH) hydrogen bonded to central carbon |
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alpha amino acids are what?
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COO-
NH3+ how they are in the body |
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Classes of proteins
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structural
contractile transport storage hormone enzyme protection |
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Structural
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provide structural components
ex: collagen, keratin |
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contractile
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move muscles
ex: myosin and actin |
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transport
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carry essential substances throughout the body
ex: hemoglobin transports oxygen |
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storage
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store nutrients
ex: casein stores protein in milk |
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hormone
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regulate body metabolism and nervous system
ex: insulin regulates blood glucose level |
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enzyme
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catalyze biochemical reactions in the cells
ex: sucrase catalyzes hydrolysis of sucrose |
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Protection
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recognize and destroy foreign substances
ex:immunoglobulins stimulate immune responses |
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non polar amino acids
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-hydrophobic
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polar amino acids
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-hydrophilic
-side chains such as OH, SH, and amide CONH2 |
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zwitterion
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-dipolar form of an amino acid
-net charge of zero |
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solid amino acids have what boiling point?
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high because the zwitterion has the properties of a salt
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isoelectric point (pI)
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positive and negative charges are equal, which gives the amino acid an overall charge of zero
least soluble in solution, clumps together |
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peptide bond
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amide bond that forms when COO- group of one amino acids reacts with the NH3+ group of the next amino acid
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dipeptide
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two amino acids linked together by a peptide bond form a dipeptide
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N-terminal
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amino group on left that is unreacted
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C-terminal
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carboxyl group on right that is unreacted
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protein
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when there are more than 50 amino acids in a chain, it is called a protein
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primary structure
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-the particular sequence of an amino acid in a peptide or protein
- determines the function of the protein ex: Glu-His-Pro |
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secondary structure
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-describes the way the amino acids next to or near each other along the polypeptide are arranged in space
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3 types of secondary structure
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alpha helix- corkscrew shape
beta pleated sheet-zigzags triple helix- braid, most common is collagen, which is found in connective tissues, blood vessels, skin, etc |
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tertiary structure
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-determines the 3D shape
-stabilized by interactions between R groups of amino acids |
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stabilizing interactions of tertiary structures
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hydrophobic
hydrophilic (polar) disulfide salt bridge hydrogen bonds |
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hydrophobic
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interactions of two non polar groups
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hydrophilic
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interactions between two polar groups
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disulfide
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covalent bonds that form between the -SH groups of cysteines
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salt bridge
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ionic bonds between side groups of basic and acidic amino acids
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globular proteins
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have compact, spherical shapes because their secondary structures of the polypeptide chain fold over on top of each other
-functions such as synthesis, transport and metabolism |
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fibrous proteins
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consist of long, thin, fiber-like shapes
-typically involved in the structure of cells and tissues |
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quaternary structure
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when a biologically active protein consists of two or more polypeptide subunits
ex: hemoglobin |
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denaturation
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occurs when there is a disruption of any of the bonds that stabilize the 2,3,4 structure
-primary is not affected -globular protein unfolds |
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5 ways of denaturation
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heat
acid and bases organic compounds heavy metal ions agitation |
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what do you need to hydroxylate?
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vitamin c
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3 structure is maintained by
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intrachain bonds:
hydrogen bonds, disulfid bond, hydrophobic interactions, salt bridges |