5. Molecules of Microbiology

Which of the following descriptions best fits the class of molecules known as nucleotides?

a) A nitrogenous base & a phosphate group.

b) A nitrogenous base & a sugar.

c) A nitrogenous base, phosphate group & a sugar.

d) A nitrogenous base, a carbohydrate, & a sugar.

The four nitrogenous bases commonly found if DNA are: 

a) Adenine, thymine, cytosine, uracil 

b) Uracil, adenine, cytosine, guanine.

c) Uracil, cytosine, guanine, thymine.

d) Adenine, thymine, cytosine, guanine.

e) None are correct.

Which of the following statements about DNA structure is true?

a) The nucleic acid strands in a DNA molecule are oriented antiparallel to each other.

b) Nucleic acids are formed through phosphodiester bonds that link complementary nucleobases together.

c) Hydrogen bonds formed between the sugar-phosphate backbones of the two DNA chains stabilize the structure.

d) The pentose sugar in DNA is ribose (containing two hydroxyl groups).

Briefly describe the components of DNA, and explain its functional relationship to RNA and protein.

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>

Match the following examples of mutagens. <IMAGE>

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.