Section I: Questions 1-10 (55pt total)

Fill in the following sentences with all appropriate words from the list that follows. Place only the chosen word(s) on your answer sheet. Words may be used more than once. (15pt total)

Endoplasmic Reticulum, Golgi Apparatus, Mitochondria, Nucleus,

Plasma Membrane, Sarcoplasmic Reticulum

1) The _______ is/are used to store calcium within cells.

2) The endomembrane system includes _______.

3) IDH can be isolated from _______.

4) Eukaryotes differ from prokaryotes in that they sequester genetic material within their _______.

5) Myocardial cells resume normal contractions after moving cations across the _______.

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Short Answers. Answer the following in complete sentences. Where appropriate, include all calculations. Calculations do not need to be in sentence format and diagrams may be hand-drawn.

6) You were hired to prepare solutions for the enzyme lab unit in Bio111. At your disposal you have prep room equipment (flasks, beakers, graduate cylinders, balances) distilled water and solid MgCl2 (MW 95.2).

a) Explain how to make 250ml of a 6% w/v solution of MgCl2. (3pt)

b) What is the concentration of MgCl2 (in mM) of the solution in 6a? (3pt)

7) Name and define the role each of the following substances play in the reaction studied in the first lab unit. (2pt each)

a) a-ketoglutarate

b) IDH

c) isocitrate

d) NADP+

Bonus: Below is the structure of one of the compounds used in lab unit one. Name the compound for +O.5pts

8) To examine the effect of increased enzyme concentration on reaction rate you plotted "activity" vs. "volume of enzyme". How did you determine activity? (What were you actually measuring, why did it change, and how is that related to the activity/reaction rate?) (5pt)

9) Linking 2 sugar molecules, linking 2 amino acids, or adding a phosphate group to a protein all require the same type of chemical reaction.

a) Name and briefly describe the chemical reaction that mediates all of these events. (4pt)

b) For each of the examples given in 9 name the specific bond/linkage that results.

(ex. The bond found between 2 amino acids is called a ---- bond) (1pt each)

Bonus Draw the bond found in each of the examples listed above. (0.5pt each)

10) You have discovered that forms of earlobe cancer are related to expression of an abnormal form of a kinase. The abnormal kinase is predicted to have a higher molecular weight than the normal form of the kinase. You have isolated samples of both forms of the kinase and are ready for further experiments.

a) What is a kinase? (4pt)

b) Describe an experiment that would demonstrate that the abnormal kinase does, in fact, have a higher molecular weight than the normal kinase. Be sure to indicate how you would be able to tell it was larger. (3pt)

c) You decide to compare the earlobe cells you study with bacterial cells and skeletal muscle cells. Hypothesize which of these cells have the greatest and the fewest number of mitochondria. Briefly explain your reasoning being sure to mention all 3 cell types. (4pt)

d) How could you collect data to test the hypothesis made in 10c? (3pt)

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Section II: Questions 1-4 (45pt total)

Answer all of the following questions. Answers must be in complete sentences. Be careful to answer the question that is asked. Brevity is encouraged.

1) When studying cellular communication it becomes evident that the same signal can often cause very different responses in different cells. Why is this the case? Provide an example that illustrates at the molecular level how these 'differential responses' help the organism function correctly. (10pt)

2) How is a membrane potential generated? Discuss the types of ion channels that act to change the membrane potential of a neuron. ('Types' refers to general class of channelà the ion that passes through the channel may be included as an example) Why might a neuron have evolved this sort of signaling within the cell? (15pt)

3) In biology the 'form' of a compound is intimately related to its function. This is the case in fertilization where sperm triggers the conversion of an egg cellular component into second messengers. Describe the general structure of the cellular component and the second messengers that result. How do these structures dictate where in the cell the second messengers will be used? (10pt)

4) Calcium is involved in many cellular communication systems. Using one example system from this unit describe how the cell controls the levels of calcium in response to a signal, what the change in calcium levels causes and how the cell returns to 'resting' concentrations of calcium. Limit your discussion to the cellular events that directly involve calcium, its levels or use. (Do not include all steps in the pathway). (10pt)