5. Molecules of Microbiology

In DNA, adenine forms ___________ hydrogen bonds with ____________.

a. Three / uracil

b. Two / uracil

c. Two / thymine

d. Three / thymine

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

Match the following examples of mutagens.

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).

A nucleotide is made of:

a. A five-carbon sugar

b. Phosphate

c. A nitrogenous base

d. All of the above

The following is a code for a strand of DNA.

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.

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.

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?

Haploid nuclei ___________.

a. contain one set of chromosomes

b. contain two sets of chromosomes

c. contain half a set of chromosomes

d. are found in the cytosol of eukaryotic organisms

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 is most likely the number of base pairs in a bacterial chromosome?

a. 4,000,000

b. 4000

c. 400

d. 40

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.

Compare and contrast the structure and components of DNA and RNA in prokaryotes.

A nucleic acid containing the base uracil would also contain __________ sugar.