This is a test from a similar course at a university far, far away. Be warned that your test may not be like this one. This is just meant to give you a sample of what is expected of you. You can print it by pressing the PRINT button of your browser.

Make sure that you answer the question asked and be careful not to use pronouns in your answers.

Identify the following with regard to the structure of an atom: (1 point each)

__________ subatomic particle that has a positive charge

__________ the smallest subatomic particle

__________ atomic number of an element that has 5 protons and 6 neutrons

__________ the atomic weight of an element that has 5 protons and 6 neutrons

Chemical Bonds

List the 4 types of interactions between atoms/molecules that were discussed in class. (2 points)

Identify the following: (1 point each)

__________ bond in which there is an unequal sharing of electrons

__________ strongest bond

__________ a bond that is due to the electrical attraction of two ions

__________ another term for a dipole to dipole interaction

__________ bond that is easily disrupted in an aqueous solution.

pH & Water

The pH of a solution is changed from 6 to 7. Did the concentration of hydrogen ions increase or decrease? (1 point)

What is the definition of pH? (What is the equation used to calculate pH) (1 point)

What is meant by the term hydrophilic? (1 point)

You are given a compound with the following formula:

C₄H₉O₃N

Would you expect this substance to be water soluble or lipid soluble? Explain why. (2 points)

 

What is the hydrogen ion concentration of a solution with a pH of 4.2 (1 point)

You have a solution of the weak acid acetic acid that undergoes the following reaction when dissolved in water.:

acetic acid <-------> acetate^- + H⁺

If you allow the reaction to reach equilibrium, and then add some H⁺, will the reaction go towards the left (and convert acetate into acetic acid) or the right (and convert acetic acid to acetate^-). (2 points)

Aspirin is a weak acid that loses a proton (and becomes an ion) in solutions where the pH is greater than 3.5. In a pH less than 3.5, the aspirin is not ionized (it does not have a charge). Would you expect aspirin to be more water soluble when dissolved in a solution with a pH of 6 or in a solution with a pH of 2. Explain your reasoning. (3 points)

Carbon

How many covalent bonds can carbon usually make with other elements? (1 point)

Match the following functional groups as described in your text: (1 point each)

-C=O

-COOH

-NH2

-C-OH

_____ hydroxyl group

_____ carbonyl group

_____ carboxyl group

_____ amino group

Macromolecules

For each of the following type of macromolecules, list their building block molecules, the specific type of bond that holds them together, and one cellular function for each. (2 points each)

a. polysaccharides

b. proteins

c. nucleic acids

List the three major classes of lipids as described in your readings and in class. List a specific, different function for each class. (3 points)

What two sugars make up lactose? (1 point)

What property is common to all lipids? (1 point)

What is meant by the primary structure of a protein? (1 point)

An alpha-helix is a type of the ____________ of the protein. (1 point)

What are the types of interactions that hold the tertiary structure of a protein together? (2 points)

What are the three parts that make up a nucleotide? (1 point)

What is meant by the term denaturation? What type of macromolecule described in class can be denatured? (2 points)

The enzyme trypsin works best when the pH of the solution is 8.0. If the pH is reduced to 3.0, trypsin will not longer be active. Based on your understanding of pH and of proteins, explain this observation. (3 points)

What is meant by the term amphipathic?

What type of lipid has this property?

What type of carbohydrate is cellulose?

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