Homework 1 (Due: Sept. 19, 2005)

Chemistry of Life

1. List the common elements found in the human body.

2. Compare covalent and ionic bonds. Indicate which type of bond is formed by the common elements listed below. If covalent, calculate how many bonds each can form.

C, H, N, O

3. Identify whether each of the following covalent bonds, C-O, C-H, N-H and O-H is polar or nonpolar, and explain how these different characteristics relate to the electronegativity of each atom involved in the bond.

4. Describe the properties of water which make it a polar solvent capable of dissolving ionic compounds and also of forming hydrogen bonds with itself and with certain covalent compounds.

5. Define hydrophobic and hydrophilic.

6. List the common functional groups found in the human body, their relative polarity and whether or not they are capable of hydrogen bonding.

7. Define amphiphilic (amphipathic) and provide an example of an amphiphilic biological molecule.

 

The Cell

1. List the major components of a eukaryotic cell.

2. Define the major function of each of the parts listed above.

3. Identify where specific biochemical processes occur in the cell.

 

Molecules of Life/Water

1. List the four major classes of biomolecules found in the human body.

2. Draw an ester bond and demonstrate how it is formed from the condensation of two common functional groups.

3. Describe the three subclasses of lipids and provide representative examples of each (drawing detailed structures not required).

4. Draw a biological membrane and explain its bilayer structure in terms of the amphiphilic nature of membrane phospholipids.

5. Give examples of common simple carbohydrates found in the human body.

6. Describe the hydrophilic nature of carbohydrates in terms of hydrogen bonding.

7. Describe the ability of water to ionize and define pH.

8. Compare water to a representative carboxylic acid and describe how their ability to ionize is represented as pH and pKa.

9. Draw an ionization curve to illustrate the concept, mathematically expressed in the Henderson-Hasselbach equation, that a pool of acid molecules is half-ionized when pH=pKa.

 

Acidosis/Alkalosis

1. Identify the most common biological weak base and its typical pKa range.

2. Describe buffering as a property of acids and bases.

3. Draw the equilibrium reaction of sodium bicarbonate in aqueous solution and list four features which help make this an effective blood buffering system.

4. Describe the dynamic state of CO2 in the body and predict the direction in which the bicarbonate equilibrium will be shifted in respiratory failure vs. hyperventilation.

5. Describe acidosis and alkalosis, give examples of how each arise, and predict how each will shift the bicarbonate equilibrium.

6. Describe the processes by which the body attempts to compensate for acidosis or alkalosis.

 

Case Study 1

Discuss how ingestion of an acid would affect the relationship between blood pH, pCO2 and bicarbonate and how such a patient would compensate for the excess acid.

Amino Acids/Proteins

1. List the two functional groups every amino acid posses.

2. Classify each amino acid according to the chemical nature of its side chain.

3. Draw the reaction in which two amino acids join to form a peptide bond.

4. Explain how a polypeptide can be hydrophobic, hydrophilic or amphiphilic based on its amino acid sequence (primary structure).

5. Define secondary structure of proteins and describe the two most common types of secondary structure.

6. Explain why proline is incompatible with an a-helix.

7. Define tertiary and quaternary structure and explain how the hydrophobic effect is a major driving force in the conformation of proteins in aqueous environments.

 

Protein Synthesis and Maturation

1. Define the terms: genetic code, codon, anticodon, degenaracy, wobble, charged tRNA and translation.

2. List the steps and state the function of amino acid activation.

3. List the types of RNA used in translation and state their functions.

4. State the function of the ribosome in translation and list its major components.

5. Diagram the process of translation.

6. Diagram the process of protein extrusion into the ER.

7. List some antibiotics and toxins that inhibit synthesis.

© Dr. Noel Sturm 2005