Solution Manual for Campbell Biology 10th Edition by Reece

Solution Manual For Campbell Biology 10th Edition by Reece Link download full: https://testbankservice.com/download/solution-manualfor-campbell-biology-10th-edition-by-reece Key to Questions 1. Meselson and Stahl, California Institute of Technology 2. Proceedings of the NationalAcademy of Science, 1958 3. National Foundation for Infantile Paralysis and the National Institutes of Health 4. density-gradient centrifugation: separation of a mixture of macromolecules, placed in a concentrated solution of cesium chloride, according to their density in a centrifuge generation time: the time between the birth of one organism (here, a bacterium) and the birth of its offspring isotope: one of several atomic forms of an element, each containing a different number of neutrons and thus having a different mass 5. Heavy nitrogen isotopes, N15 6. DNA composed of N15 has greater density. Higher-density material is to the right in the photograph.

7. (a) About one-half; (b) by 4.3 hours, the band of DNA begins to narrow; and by

19.2 hours, the band was fairly narrow; (c) middle.

8. The line with two peaks is a graph of the darkness of the band images in Figure 2a, showing the position of the same two bands along the same horizontal scale of density.

9. They added the growing bacteria culture to a growth medium containing a tenfold excess of N14H4Cl. 10.

The density of DNA varies directly with the fraction consisting of N 15.

Therefore, the relative position of the band between the band of fully labeled DNA and the band of fully unlabeled DNA indicates how much of the DNA was labeled with N15.

11.

(a) 0.81 hours for experiment 1 and 0.85 hours for experiment 2; (b) about

3.5 hours for 4 generations; (c) switch bacteria from growth media containing only N15 molecules to growth media containing only N14 molecules.

12.

(a) After 1.0 generation, the peak DNA density was lower than the density

of initial DNA. (b) After two generations, there were two peaks, and one of those was at the same density as the peak after one generation. (c) None

One generation time after the addition of N14, these half-labeled or “hybrid�

13.

molecules alone are observed.Thus, all daughter molecules are half-labeled.

14. (a)

(b)

(c)

15.

If the two images in each pair were different, there would be two peaks in

sketch a.

16.

The two chains separate, then each chain serves as the template for the

synthesis of its complement.

17.

(a) Bases (purines and pyrimidines); (b) You could label the phosphate with

a radioisotope of phosphorus, P32, or label the deoxyribose sugar with a radioisotope of carbon, C14.

18.

In “conservative� replication, all the atoms of the original DNA molecule

would be together in one of the daughter molecules and the other daughter molecule would be made from all new (nonlabeled) atoms.

19.

As long as the pairs of nitrogen bases are present in the DNA fragments, we

can still see the proportions of heavy and light nitrogen that support the WatsonCrick model of replication.

20.

You could label a different part of the DNA molecule, as suggested in

question 16, and see if the density results are the same. You could repeat these tests with another species of bacteria or with cells from a eukaryotic organism to see if the results can be generalized to all cells.