1. 7.5
Proteins

2. 1°- sequence of amino acids in the chain
7.5.1 Explain the four levels of protein structure, indicating the significance of each level.
1°- sequence of amino acids in the chain
2°- coils; H bonds; collagen, keratin have repeated sequences so have lots coils
α-helix: hair, wool, horns, feathers
β-pleated sheet: silk

3. 7.5.1 Explain the four levels of protein structure, indicating the significance of each level.
3°- helix folding; R groups interact: hydrophobics cluster together on inside, hydrophilics cluster on outside,
disulfide bridges between S of 2 R groups (cov bond), ions may be cofactors

4. common in large globular proteins (hemoglobin—2 α chains, 2 β chains)
7.5.1 Explain the four levels of protein structure, indicating the significance of each level.
4°- different polypeptides combine w/H bonds, +/- attractions, hydrophobic forces, and/or disulfide bridges;
common in large globular proteins (hemoglobin—2 α chains, 2 β chains)
“conjugated proteins” - binding of prosthetic group: each chain also has a Heme group, contains Fe (not a polypeptide)
chlorophyll, electron transport chain enzymes are other examples

5. Main level of organization 2° is most important 3° is most important
7.5.2 Outline the difference between fibrous proteins & globular proteins, with reference to two examples of each protein type.
Fibrous
Globular
Shape
Long
Tightly folded
Solubility
Insoluble in water
Soluble in water
Main level of organization
2° is most important
3° is most important
Function
Structural (they ARE something)
Functional (they DO something)
Examples
Collagen, keratin, myosin
Hemoglobin, enzymes, antibodies, hormones

6. 7.5.3 Explain the significance of polar and non-polar amino acids.
20 common amino acids
8 w/non-polar R groups
Insoluble in water
Cluster center (4° structure)
More non-polar AAs  less soluble in water
Cell membrane (phospholipid bilayer): polar on outside, non on inside
Protein situated with hydrophilic portions to outside of membrane, hydrophobic sections to center

7. Structure: collagen (fibrous, structural ptn) builds tendons & in skin
7.5.4 State four functions of proteins, giving a named example of each:
Structure: collagen (fibrous, structural ptn) builds tendons & in skin
Enzymes: all are globular
starch –amylase maltose
Transport: hemoglobin (globular, conjugated); readily, reversibly binds Oxygen b/c of heme group

8. Hormones: some are ptns (some are steroids)
7.5.4 State four functions of proteins, giving a named example of each:
Hormones: some are ptns (some are steroids)
Insulin
Contractile: muscle contractions (actin, myosin)
Defense: antibodies/immunoglobulins for defense against antigens