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Problem 2.1a
What is a chemical element?
Problem 2.1a
Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a cell can then be followed. This process is the basis for questions 1-3.
Assume E. coli bacteria are grown in a nutrient medium containing the radioisotope ¹⁶N. After a 48-hour incubation period, the ¹⁶N would most likely be found in the E. coli’s
a. carbohydrates.
b. lipids.
c. proteins.
d. water.
e. none of the above
Problem 2.10a
Classify each of the molecules on the left as an acid, base, or salt. The dissociation products of the molecules are shown to help you.
MgSO₄ → Mg²⁺ + SO²₄⁻
Problem 2.2a
DRAW IT Diagram the electronic configuration of a carbon atom.
Problem 2.2a
Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a cell can then be followed. This process is the basis for questions 1-3.
If Pseudomonas bacteria are supplied with radioactively labeled cytosine, after a 24-hour incubation period this cytosine would most likely be found in the cells’
a. carbohydrates.
b. DNA.
c. lipids.
d. water.
e. proteins.
Problem 2.3a
What type of bond holds the following atoms together?
a. Li+ and Cl- in LiCl
b. carbon and oxygen atoms in methanol
c. oxygen atoms in O₂
d. a hydrogen atom of one nucleotide to a nitrogen or oxygen atom of another nucleotide in:
<IMAGE>
Problem 2.3a
Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a cell can then be followed. This process is the basis for questions 1-3.
If E. coli were grown in a medium containing the radioactive isotope ³²P, the ³²P would be found in all of the following molecules of the cell except
a. ATP.
b. carbohydrates.
c. DNA.
d. plasma membrane.
e. complex lipids.
Problem 2.6a
Classify the following as subunits of either a carbohydrate, lipid, protein, or nucleic acid.
a. <IMAGE>
b. <IMAGE>
c. <IMAGE>
d. Thymine nucleotide
Problem 2.6a
Which of the following is an organic molecule?
a. H₂O (water)
b. O₂ (oxygen)
c. C₁₈H₂₉SO₃
d. FeO (iron oxide)
e. F₂C=CF₂ (Teflon)
Problem 2.7a
Classify each of the molecules on the left as an acid, base, or salt. The dissociation products of the molecules are shown to help you.
HNO₃ →H⁺ + NO⁻₃
Problem 2.8a
Classify each of the molecules on the left as an acid, base, or salt. The dissociation products of the molecules are shown to help you.
H₂SO₄ →2H⁺ + SO²₄⁻
Problem 2.8a
DRAW IT The following diagram shows the bacteriorhodopsin protein. Indicate the regions of primary, secondary, and tertiary structure. Does this protein have quaternary structure?
<IMAGE>
Problem 2.9a
Classify each of the molecules on the left as an acid, base, or salt. The dissociation products of the molecules are shown to help you.
NaOH → Na⁺ + OH⁻
Problem 2.9a
DRAW IT Draw a simple lipid, and show how it could be modified to a phospholipid.
Problem 6.2a
Macronutrients (needed in relatively large amounts) are often listed as CHONPS. What does each of these letters indicate, and why are they needed by the cell?
Problem 6.6a
The term trace elements refers to
a. the elements CHONPS.
b. vitamins.
c. nitrogen, phosphorus, and sulfur.
d. small mineral requirements.
e. toxic substances.
Problem 8.1a
Briefly describe the components of DNA, and explain its functional relationship to RNA and protein.
Problem 8.2a
Identify and mark each of the following on the portion of DNA undergoing replication: replication fork, DNA polymerase, RNA primer, parent strands, leading strand, lagging strand, the direction of replication on each strand, and the 5′ end of each strand. <IMAGE>
Problem 8.3a
Match the following examples of mutagens. <IMAGE>
Problem 8.4a
The following is a code for a strand of DNA.<IMAGE>
a. Using the genetic code provided in Figure 8.8, fill in the blanks to complete the segment of DNA shown.
b. Fill in the blanks to complete the sequence of amino acids coded for by this strand of DNA.
c. Write the code for the complementary strand of DNA completed in part (a).
d. What would be the effect if C were substituted for T at base 10?
e. What would be the effect if A were substituted for G at base 11?
f. What would be the effect if G were substituted for T at base 14?
g. What would be the effect if C were inserted between bases 9 and 10?
h. How would UV radiation affect this strand of DNA?
i. Identify a nonsense sequence in this strand of DNA.
Problem 8.7a
Which sequence is the best target for damage by UV radiation: AGGCAA, CTTTGA, or GUAAAU? Why aren’t all bacteria killed when they are exposed to sunlight?
Problem 27.7a
Outline the treatment process for drinking water.
Problem 27.8a
The following processes are used in wastewater treatment. Match the stage of treatment with the processes. Each choice can be used once, more than once, or not at all.
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Problem 27.9a
All of the following are effects of water pollution except
a. the spread of infectious diseases.
b. increased eutrophication.
c. increased BOD.
d. increased growth of algae.
e. none of the above; all of these are effects of water pollution.
