many carbon atoms and which functional groups (types and numbers) does an aldopentose have?
18- Which of the following polysaccharides have a structural function? Glycogen, Cellulose, Starch, peptidoglycans, chitin. What is the main function of those of the list that are not structural (indicate in which type of cell)?
19- What is the difference between a saturated and an unsaturated fatty acid? What influence does the degree of saturation of fatty acids have on the physical properties of the lipids that they make up? Explain why.
20- What is the general structure of a phospholipid? How do you explain its amphipathic nature? Why is it reasonable to claim that life would not exist without phospholipids?
21- Proteins are central to all a cell is made up of, can be or can do: List the various functions of proteins.
22- Draw the general structure of an amino acid. Which types of functional groups are present in every amino acid? Which part of the structure gives each amino acid its distinctive characteristics? Are amino acids polar or non-polar molecules?
23- Give a detailed classification of the 20 natural amino acids based on the structure of their side chains.
24- How does the peptide bond form? (Illustrate)
25- Bradykinin is a peptide that is released when cells are damaged; based on the three-letter code of amino acids, the sequence of the peptide is the following: Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg.
a. Write the one letter sequence of the peptide.
b. Write the full name of the peptide.
c. Which percentage of nonpolar amino acids does this peptide contain?
26- Structural organization of proteins:
a. List the different levels?
b. What are the different types of chemical bonds involved in each level?
c. What is the difference between a polypeptide and a protein?
d. What is a homotetrameric enzyme?
e. What is a heterodimeric receptor?
27- Briefly describe the alpha helix and the beta sheet. Why are these structures so common in proteins?
28- What is the difference between an antiparellel and a parallel beta sheet.