Question 1

The protein of T2 bacteriophage is labeled with ³⁵S and the DNA with ³²P. Where would one detect most of the ³²P if the T2 bacteriophage were allowed to infect the bacteria? A) on the phage coat surrounding the T2 bacteriophage B) on the membrane of the infected bacteria C) inside the T2 bacteriophage capsid D) inside the infected bacteria E) The ³²P would be equally distributed within the T2 bacteriophage and infected bacteria.

Accepted Answer

The ³²P labels the DNA of the T2 bacteriophage, which is injected into the bacteria during infection. Thus, most of the ³²P would be found inside the infected bacteria.

Question 2

Which of the following scientist-discoveries is mismatched?&#10;A) Watson, Crick, Wilkins, and Franklin-DNA structure&#10;B) Avery, MacLeod, and McCarty-DNA is the genetic material&#10;C) Meselson and Stahl-mechanism of DNA replication&#10;D) Griffith-chromosomes&#10;E) Hershey and Chase-DNA is the genetic material of bacteriophage

Accepted Answer

Griffith is known for discovering the "transforming principle" in bacteria, not chromosomes.

Question 3

All of the following nucleotide bases are pyrimidines EXCEPT&#10;A) adenine.&#10;B) thymine.&#10;C) cytosine.&#10;D) uracil.&#10;E) cytosine and thymine.

Accepted Answer

Adenine is a purine base, not a pyrimidine base.

Question 4

What is the complement DNA strand to 5?-ATTCGGTGA-3??&#10;A) 5?-TAAGCCACT-3?&#10;B) 3?-CGGATTGTC-5?&#10;C) 5?-CGGATTGTC-3?&#10;D) 3?-TAAGCCACT-5?&#10;E) 3?-ATTCGGTGA-5

Accepted Answer

DNA strands are complementary and antiparallel. The complement to A is T, to T is A, to C is G, and to G is C. The original strand is 5' to 3', so the complement is 3' to 5'.

Question 5

Which of the following does NOT belong with the others?&#10;A) replication fork&#10;B) single-stranded binding proteins&#10;C) DNA ligase&#10;D) topoisomerase&#10;E) helicase

Accepted Answer

DNA ligase is different because it is involved in the process of joining DNA fragments together, such as in DNA replication's lagging strand synthesis and in DNA repair, rather than unwinding or stabilizing the DNA helix like the other options.

Question 6

Unlike the leading strand, ______________ are made in replicating the lagging strand of DNA.&#10;A) primers&#10;B) nucleases&#10;C) Okazaki fragments&#10;D) pyrophosphates&#10;E) DNA polymerases

Accepted Answer

Okazaki fragments are short sequences of DNA nucleotides which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication.

Question 7

________ attaches DNA sequences at the ends of eukaryotic chromosomes.&#10;A) Polymerase&#10;B) Ligase&#10;C) Telomerase&#10;D) Topoisomerase&#10;E) Primase

Accepted Answer

Telomerase is the enzyme responsible for adding repetitive nucleotide sequences to the ends of eukaryotic chromosomes, known as telomeres, to protect them from degradation and maintain chromosome integrity during replication.

Question 8

Which of the following statements about telomeres is INCORRECT?&#10;A) Telomeres are produced by telomerase.&#10;B) Telomeres are found at the ends of DNA.&#10;C) Telomeres are short repeat sequences.&#10;D) Telomeres would predominate more in cells of older than younger individuals.&#10;E) Telomeres are crucial to the viability of a cell that replicates often.

Accepted Answer

Telomeres are protective caps at the ends of chromosomes that shorten with each cell division. They do not predominate more in older individuals; in fact, they become shorter as individuals age, which is associated with cellular aging and reduced cellular function.

Question 9

Where would one expect to find the most telomerase?&#10;A) male germ cells that give rise to gametes&#10;B) skin cells from a 60-year-old individual&#10;C) skin cells from a 2-year-old individual&#10;D) a nerve cell from a 60-year-old individual&#10;E) a nerve cell from a 2-year-old individual

Accepted Answer

Telomerase is an enzyme that adds DNA sequence repeats ("TTAGGG" in all vertebrates) to the 3' end of DNA strands in the telomere regions, which are found at the ends of eukaryotic chromosomes. This enzyme is particularly active in cells that divide frequently or have the potential to divide frequently, such as germ cells (which give rise to gametes), stem cells, and certain white blood cells. Male germ cells need to maintain their telomeres for fertility over the lifespan of an individual, hence they have high levels of telomerase activity. In contrast, somatic cells like skin and nerve cells have lower levels of telomerase activity, which decreases as an individual ages, leading to telomere shortening and cellular aging.

Question 10

During the DNA replication process, which of the following organisms would have the fewest origins of replication per cell?&#10;A) a rapidly dividing Streptococcus bacterium&#10;B) a yeast cell&#10;C) a human&#10;D) a young oak tree&#10;E) a fruit fly

Accepted Answer

Streptococcus bacteria, being prokaryotic organisms, typically have a single circular chromosome that initiates replication at a single origin of replication. In contrast, eukaryotic organisms such as yeast cells, humans, young oak trees, and fruit flies have multiple chromosomes that each contain multiple origins of replication to facilitate the replication of their larger and more complex genomes.

Question 11

Studies by Avery, MacLeod, and McCarty with different strains of bacteria and those by Hershey and Chase with T2 bacteriophage determined that proteins are highly complex molecules that form the genetic material for bacteria and viruses.

Accepted Answer

The answer of Studies by Avery, MacLeod, and McCarty with...

Question 12

The progressive shortening of telomeres in DNA correlates with cell senescence.

Accepted Answer

The answer of The progressive shortening of telomeres in DNA...

Deck 11: Nucleic Acid Structure, DNA Replication, and Chromosome Structure