click below
click below
Normal Size Small Size show me how
CHM 140
CH 22
Question | Answer |
---|---|
List the 8 functions of proteins in the body and give an example of each. | a)structure (collagen) b)catalysts(enzymes), c)movement(myosin), d)transport(hemoglobin), e)hormones(insulin,GH), f)protection(antibodies), g)storage(casein), h)regulation(of gene expression) |
What 3 substances make up the majority of connective tissue? | collagen, elastin, proteoglycans |
What 5 places in the body is collagen found? | tendons, skin fiber, blood vessels, bone, and cartilage |
What is the most abundant protein in the body? | collagen |
Where in the body is elastin found? | ligaments |
Where are proteoglycans found? | extracellular matrix |
Where in the body is a-keratins found? | hair, nails, and much of the outer layer of skin |
What is the purpose of fibrinogen in the blood? | blood clotting |
What are the two types (shapes) of proteins and what is the structure of each? | fibrous (ropelike, linear) and globular (circular, compact) |
Where is th amino groups located with respect to the carbonyl carbon? | on alpha carbon |
A zwitterion is neutral but carries both a ___and ___ charge. | + and - |
Describe what the isoelectric point (pI) is. | pH at which the majority of molecules of a compound in solution have no net charge |
What two atoms does a peptide bond bind together. What is the name of this functional group? | C and N - amide group |
What is the difference between a polypeptide and a protein? | # of amino acids: protein has 30 more than a polypeptide |
C-terminal amino acid- | amino acid at the end of a chain having a free -COO-group |
N-terminal amino acid | amino acid at the end of a chain having a free -NH3+group |
primary structure | sequence of amino acids in a polypeptide chain |
secondary structure | conformations of amino acids in localized regions of a polypeptide chain |
tertiary structure | overall conformation of a polypeptide chain |
quaternary structure | arrangement of two or more polypeptide chains into a noncovalently bonded aggregation |
What is a glycoprotein? | a protein to which one or more carbohydrate units are bonded |
What is denaturation? | process of destroying the native conformation of a protein by chemical or physical means-can disrupt the secondary, tertiary, or quatenary structure |
What are the 3 secondary structures that we studied in class? | a-helix, b-pleated sheet, collagen triple helix |
An a-helix is most commonly a right or left handed helix? | right |
How many amino acids per turn in a a-helix? | 3.6 |
Describe the positions of the carbonyl (C=O) groups and the amine hydrogens (N-H) in the a-helix. | The amine (N-H) groups point in direction of spiral almost parallel with helix and carbonyl (C=O) groups pointing in opposite direction. |
Describe the positions of the R group in the a-helix. | The R groups are perpendicular to the axis of the helix |
What interaction holds a protein in the a-helical form? | hydrogen bonding |
Describe the positions of the carbonyl (C=O) groups and the amine hydrogens (N-H) in the b-pleated sheet. | The C=O and N-H groups of peptide bonds from adjacent chains point toward each other and are in the same plane so that hydrogen bonding is possible between them |
Describe the positions of the R group in the b-pleated sheet. | R- groups on any one chain alternate, first above, then below the plane of the sheet, etc. |
What interaction holds a protein in the b-pleated sheet form? | hydrogen bonding |
Describe the structure of collagen. | Consists of three helical polypeptide chains wrapped around each other in a ropelike twist to form a triple helix called tropocollagen |
What 3 amino acids make up the majority of collagen? | Almost 2/3 of collagen is made up of the amino acids: proline, hydroxyproline, and glycine |
What 4 interactions hold the protein in its tertiary structure? | a)covalent bonds, b)hydrogen bonding, c)salt bridges, d)hydrophobic interactions |
What 3 interactions hold the protein in its quaternary structure? | a)hydrogen bonding, b)salt bridges, c)hydrophobic interactions |
The glycosidic bond between a saccharide and a protein side chain can be through either a___ or a ____ atom. | O or N |