Term
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Definition
| a polymer of amino acids...the function of a protein depends on its specific conformation |
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Term
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Definition
| structural support, storage, transport of other substances, intercellular signaling, movement, and defense against foreign substances |
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Term
| Most proteins are _____ and regulate _____ of the cell. |
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Definition
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Term
| Proteins are the most structurally complex molecules known. Each TYPE of protein has a ________ |
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Definition
| complex 3-D shape or conformation |
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Term
| All protein polymers are constructed from what? |
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Definition
| the same set of 20 monomers called AMINO ACIDS |
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Term
| Definition or Polypeptides |
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Definition
| polymer of amino acids connected in a specific sequence |
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Term
| Amino acids consist of four components attached to a central carbon called: |
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Definition
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Term
| What are the components of amino acids? |
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Definition
1. hydrogen atom
2. carboxyl group
3. amino group
4. variable R group (or side chain)
- differences in R groups produce the 20 different amino acids |
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Term
| What do the physical and chemical properties of the R group determine? |
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Definition
| the unique characteristics of a particular amino acid |
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Term
| There are 3 different classes of amino acids: |
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Definition
1. one group has hydrophobic R groups
2. another has polar R groups, making them hydrophilic
3. the last group includes those with functional groups that are charged (ionized) at cellular pH
(some R groups are bases, others are acids) |
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Term
| How are amino acids joined together? |
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Definition
| When a dehydration reaction removes a hydroxyl group from the carboxyl end of one amino acid and a hydrogen from the aminor group of another |
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Term
| What is the resulting covalent bond AFTER amino acids are joined together? |
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Definition
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Term
| Repeating the process over and over creates a long polypeptide chain. |
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Definition
The repeated sequence (N-C-C) is the polypeptide backbone
(attached to the backbone are the various R groups) |
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Term
| A protein's function depends on what? |
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Definition
| it's specific conformation --> a functional protein consists of one or more polypeptides that have been precisely folded, into a unique shape |
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Term
| It is the _____ that determines the _____ conformation of the protein. |
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Definition
| order of amino acids, three-dimensional |
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Term
| Specific conformation of a protein determines its function. |
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Definition
In almost every case, the function depends on its ability to recognize and bind to some other molecule.
(ex: antibodies bind to particular foreign substances that fit their binding sites) |
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Term
| The folding of a protein from a chain of amino acids occurs _____. |
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Definition
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Term
| Three levels of structure are used to organize the folding within a SINGLE POLYPEPTIDE: |
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Definition
| primary, secondary, and tertiary structure |
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Term
| When is there a QUARTERNARY structure? |
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Definition
| when 2 or more polypeptides join to form a protein |
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Term
| What is the primary structure of a protein? |
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Definition
its unique sequence of amino acids
(the precise primary structure of a protein is determined by inherited genetic information) |
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Term
| How does the secondary structure of a protein come about? |
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Definition
results from hydrogen bonds at regular intervals along the polypeptide backbone
(typical shapes that develop from secondary are coils [an alpha helix] or folds [beta pleated sheets]) |
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Term
| How is tertiary structure determined? |
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Definition
| by a variety of interactions among R groups and between R groups and the polypeptide backbone. |
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Term
| What covalent bonds stabilize the tertiary structure? |
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Definition
| Disulfide bridges that form between the sulfhydryl groups (SH)of cysteine monomers |
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Term
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Definition
| globular protein with 2 copies of 2 kinds of polypeptides |
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Term
| How can a protein's conformation change? |
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Definition
in response to the physical and chemical conditions
(alterations in pH, salt concentration, temperature or other factors can unravel or denature a protein) |
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