For Those with old Editions of the Problem Book (14th, 15th, or 15th revised)--Updated08/29/2003

The following changes were new in the 16th edition. You need this list to update from the 15th edition, revised, to the 16th edition.

     2-8. Instead of poly gly and poly pro, the two polypeptides are P1 and P2. P1 contains all 20 amino acids except pro. P2 has the same sequence of amino acids as P1, except that 4 of the amino acids with neutral side chains have been replaced by proline. P1 sediments more rapidly in the 'fuge.

    4-2. Add Part F: "What (if any) are the relationships of K_eq, ΔG, and/or ΔG^o to the concentration of starting materials(s)?

    4-8 Part B. Add: "Assume that the intracellular concentrations of A and B do not differ from each other by more than a factor of 100."

    4-11 Part C. The question should read: "Suppose you try to ferment some glucose to ethanol in a test tube. You add all the enzymes of ethanol fermentation except you forget to add the one(s) for conversion of pyruvate to ethanol + CO₂. You start..."

    4-12 Part D. Change "acetate" to "pyruvate." (Note also the correction below.)

    5-1. Part B (iv). Question should read: "Consider the two carbon sources mentioned, glucose and lactate. Which one(s) would you feed yeast if you wanted them to make wine? Would either one do?

    5-11 Part B. There are now 4 parts, not 3. Questions should read as follows:
        B-1. Same question as in A-1.
        B-2. Are the vesicles "right side out" or "wrong side out?" Explain how you know and how the vesicle membranes in part B are orientated relative to their positions in a normal mitochondrion. (This used to be part B-3.)
        B-3. Where did the NAD get oxidized this time -- on the inside, outside or both? (This used to be part B-2.)
        B-4. Propose an explanation for the lack of change of ADP concentration in this experiment. (This is new.)

    5-13 Part C. Replace "in the usual way" with "in isolated mitochondria."

    8R-1 Part C. Change "alleles" to "copies."

    10-2 Part C. Add to end of C: "How can you test your hypothesis?"

    11-2 Part C. The first choice on the third line should be (growth on lactose-containing medium where lactose is the only carbon source.)

    11-6. Assume each mutant strain has a single chromosomal mutation. At the end of the problem, add this note:

If you find this problem difficult, it may help to draw out the DNA/genes/mutations of the hosts and the donors. Then try to figure out the steps in each procedure. What did the experimenters actually do with the DNA's, viruses, bacteria, etc.?  What happened to the donor DNA's? (A flow diagram may help.) You can't use a simple easy-to-memorize rule to be sure what you are dealing with -- for example, the word "often" or "common" doesn't always mean it is complementation, although it usually points in that direction.  You have to be careful to put all the facts together and not rely on one or two key words, which may be misleading.

    11-8. Assume normal virus infections produce 500 progeny per infected cell. In other words, add one more line to the table, with "normal" in the left column and "500" in the right column. 

    11-10. Add: "Unclear about how to answer part A?  Ask yourself the following question: In these experiments, what is happening? Complementation, recombination (crossing over), or both?"

    11-15. Add to end of part A: "Remember the donor is arg-  not arg⁺." Add to end of part D: "Remember the plasmid is circular, so A his BCD = his BCDA = DCB his A etc."

    12R-2. The last line of the introduction should read "2 base pairs near the beginning of the gene, after the first ATG (in the sense strand)."

    13-7. The 2nd sentence in the problem should read: "You cut the plasmid once and insert a human DNA fragment...." Part A should read: "If you cut the plasmid once and heat..."

    13-9 Part B-2. The second sentence should read: "Then you treat the hybrids with a ss-specific DNase -- an enzyme that breaks down single stranded (ss) DNA only. It does not digest double stranded DNA. After this you denature....."

Problem Book (2001: 15th edition revised) The date indicates when the error was detected and the correction posted. The corrections have been rearranged to follow the order of the problems and ans.
           
Corrections to the problems:

(9/11/01) Problem 1-5: 1-5 should be considered a starred problem.

(9/19/02) Problem Set 2.  2-16 & 2-18. The picture after 2-16 belongs to 2-18.

(9/28/01) Problem 3-3:  There is a typo in part B. The x-intercept = -1 /Km,
not 1/ Km as the problem states. The kinetics handout has it correctly.

(9/19/02) Problem 4-12. The formatting is messed up. The phrase "to a cell extract which" is in the wrong place.The question should read: "Suppose one adds pyruvate in which only the middle carbon atom is radioactive to a cell extract which is actively carrying out the reactions of the Krebs cycle." Then the structure of the acetate and the labeled carbon should be shown as a picture.

(9/19/02) 5-15 Part B (i). The last word in the line should be "stop" not "step."

(9/11/01) Problem 10-8, Part E. End of first line should read "arg^- strep^S" not "arg^! strep^S."

(11/13/01) Problem 13R3, part E. It should read "Suppose the bacteria that get the hybrid plasmid are cys-" = etc. My copy looks like it says cys!

(12/9/01) Problem 13R5. The Diagram for prob. 5 is messed up in the revised edition. The
bar that is to the left of A at position 3 should be in the C column. I have no idea how it got into the wrong place! (It is okay in the 15th ed., unrevised)

(12/9/01) Problem Set 15. There are 9 problems in problem set #15. The one labeled "15-18" is really 15-8.

Corrections to the Answers, 15th ed. revised

(9/19/02) Key to problem 3-5, part B. Change "E_B" to "E_o."

(9/19/02)  Key to 4-2, 4-4, 4-7, 4-9, & 4-16 . Wherever it says "ΔGE" it means ΔG^o.  In 4-16, Δ₂G = ΔG.

(9/19/02) Key to 5-5 part E. Replace the "6" in line one with an arrow.

(12/13/01) Key to Problem Sets 9, 10. By some process unknown to me, the fraction "1/2" has morphed into the integer "2" in many places. So if it says "2" as the answer, and you think the answer is "1/2" you are probably right. Places where the error occurs: 9-1D, 9-2B & C, 9-3 C, 9-5 C (2), 9-9 C, 9-10 A (2) , 10-3 A and B, 10-11, &10-15 A (2). In all these answers, replace "2" with "1/2." Please let me know if you find any other suspicious "2's." (Note: the fractions are correct in the 15th edition, unrevised.)

(9/19/02) Key to 10R-3, part C. Type #1 is AAbb not Aabb.

(9/19/02) Key to 10R-4, part C. In F2, the X^Ry and X^Wy  individuals are male, not female.

(9/19/02) Key to 10R-5. In the note, line 2, the "a" with an accent should be an arrow.

Problem Book (2000: 15th edition)

10-16. Answer to C. Number given is correct, but explanation is not. You are looking for a parental offspring/gamete, not a recombinant one. 39% = chance of getting an aB/ab offspring =  chance of getting an aB gamete = 1/2 total parentals.

9-10. Part B. Problem should read "Suppose....that 2 tall parents have many offspring, and all the males are tall but 1/2 the females are short." Omit the word "short" from the first sentence in part B.

8-4. Part C. Answer reads " 1-4 (Ab + ab ) is the same as 2-3 (Ab + aB)."  It should say " 1-4 (AB + ab) is the same as....."

7-12. Part C(i). Answer given assumes only P and A sites exist on the ribosome, and there is no E site. (It's an old question.)  Question should be revised to read "When tRNA ala is ready to leave the P site of the ribosome, what tRNA will arrive next? (As question is currently written, answer would be none -- when the tRNA ala is ready to exit the E site, the last tRNA, tRNA pro,  has presumably already arrived.)

Key to 7-20. There are 2 typos in the sentence beginning in the middle of line 4 under "details." The sentence should read:  If the finished protein has no met on its amino (not carboxyl) end, then the coding part of the mRNA will have at least 301 codons (not 303).

2-16 & 2-18: 9/25/00 The current picture after the answer to 2-16 belongs to 2-18.

1-11C    9/18/00  The answer should be ethanolamine, not choline. Choline has 3 methyl (-CH3) groups attached ot the amine N instead of the H's present in ethanolamine, and pictured in the problem.

1-23: Answer to prob. 1-23 could be expanded to: In glucose, the conformation of the hydroxyls at C2, C3 and C4 are constants as they are not on an anomeric carbon, and in glucose are always equatorial and out. (This fact need not not be memorized, as you are told to consult a diagram of glucose in the chair conformation.) In galactose, it is stated that the orientation of the H and OH at C4 are opposite that of glucose. Thus in galactose, the the OH must be axial rather than equatorial, and so the H must be equatorial.

Problem Book, 14th Edition:

Answer to 10-16. D. Last sentence should read: All the offspring will be Ab/Ab, aB/aB or Ab/aB in ratio of 1:1:2.

Answers to Problem Set 15: Ans. to 15-1, 15-2 & 15-6 to end are OK. Answers given to 15-3 & 15-4 are really the answers to 15-4 & 15-5. Answer to 15-3 was accidentally omitted. Answer given to 15-5 should not be there -- it is the answer to 12R-5.
So, cross out answer to 15-5. Change 15-3 --> 15-4 & 15-4 -->15-5. Then add the following answer to 15-3:
A. Dominant.
B. On an autosome.  If it were sex linked, both daughters of "right hand" marriage would be affected.
C. 0.2
D. 64% (because population is in equilibrium)

*13-15. Question A2 was omitted. Add A2 below and change current A2 to A3 and change current A3 to A4.
A2 should read: The length of the primary transcript of gene X is _________ . (Choices for A2-A4 are the same.) Note answer to 13-15 (see star key 13) has also been corrected -- some ">" signs were accidentally omitted in answers to A4 and D.

7-8A. Answer has typo in the DNA sequence. Last 4 bases should be GUCA.
7-9.  Answer should read "Complementary to the rRNA and different pyrimidines.
12-5. Look back at problem 7-7, not 7-5.1-20, page 9: A, D, and E should be A, B, and C (9/20/99)
11-6. Should be starred.
7-14. Answer to part B has a typo. It says "cys-tRNA" instead of "lys-tRNA" in line 5 of part B.
6-13, part 2-C. Short version of correction: Answer is 8, not 6. We forgot to add in two short-short molecules (from replication of the shorter-short ones). See Long Version of Correction for a table and detailed explanation.
5-11, page 37. Last sentence of questions should say 6 (not 3) mmoles of ADP and Pi (each) used up.
Last sentence of questions should say 6 (not 3) mmoles of ADP and Pi (each) used up.
5-8: answer should be 30000 g not 3000 g.
4-7: This question is starred, but the answer is actually in the back of the book, not on the Web site.
2-3. Answer to 2-3, Part B was accidentally omitted. Answer is zero.
1-22-D: skip
1-22-A-1. Should read "amide or peptide bond"

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