1.
The process that copies a DNA molecule:
Correct Answer
A. Replication
Explanation
Replication is the correct answer because it is the process that copies a DNA molecule. During replication, the DNA molecule unwinds and separates into two strands, and each strand serves as a template for the synthesis of a new complementary strand. This results in two identical copies of the original DNA molecule. Transformation is a process by which foreign DNA is introduced into a cell, and base pairing is a fundamental principle in DNA where adenine pairs with thymine and cytosine pairs with guanine.
2.
An enzyme that joins individual nucleotides to produce a new strand of DNA:
Correct Answer
B. DNA polymerase
Explanation
DNA polymerase is the correct answer because it is an enzyme responsible for the synthesis of new DNA strands. It catalyzes the addition of individual nucleotides to the growing DNA chain, using a template strand as a guide. Telomerase, on the other hand, is an enzyme involved in the maintenance and replication of telomeres, the protective caps at the ends of chromosomes. Telomeres themselves are repetitive DNA sequences that do not directly join nucleotides to produce new DNA strands.
3.
In eukaryotic cells, replication can begin at:
Correct Answer
A. Hundred of places on the DNA molecule
Explanation
In eukaryotic cells, replication can begin at hundreds of places on the DNA molecule. This is because eukaryotic DNA is linear and much longer than prokaryotic DNA. The replication process involves the unwinding of the DNA double helix and the formation of replication forks. These replication forks can initiate at multiple sites along the DNA molecule simultaneously. This allows for faster replication and ensures that the entire DNA molecule is replicated efficiently.
4.
In DNA, the fit between thymine and adenine, and the fit between cytosine and Guanine is called:
Correct Answer
C. Base pairing
Explanation
Base pairing refers to the specific pairing of nucleotide bases in DNA. Adenine always pairs with thymine, and cytosine always pairs with guanine. This complementary base pairing is crucial for DNA replication and transcription, as it ensures that the genetic information is accurately copied and transferred. Therefore, base pairing is the correct term to describe the fit between thymine and adenine, and cytosine and guanine in DNA.
5.
The first step in DNA replication is:
Correct Answer
B. The strands of the DNA separate.
Explanation
During DNA replication, the first step is the separation of the two strands of the DNA molecule. This separation is facilitated by enzymes that break the hydrogen bonds between the base pairs, causing the double helix structure to unwind. Once the strands are separated, new bases are added to each strand following the rules of base pairing, where adenine pairs with thymine and guanine pairs with cytosine. This process results in the formation of two identical DNA molecules, each consisting of one original strand and one newly synthesized strand. Therefore, the correct answer is "The strands of the DNA separate."
6.
What enzyme associated with DNA replication connects Okazaki fragments?
Correct Answer
B. DNA Ligase
Explanation
DNA Ligase is the correct answer because it is the enzyme responsible for connecting or joining the Okazaki fragments that are formed during DNA replication on the lagging strand. Okazaki fragments are short segments of DNA that are synthesized in the opposite direction of the replication fork, and DNA Ligase plays a crucial role in sealing the nicks or gaps between these fragments by catalyzing the formation of phosphodiester bonds. This process ensures the continuous synthesis of the lagging strand during DNA replication. DNA Primase is responsible for synthesizing RNA primers, and DNA Polymerase is responsible for adding nucleotides to the growing DNA strand.
7.
What enzyme associated with DNA Replication produces an RNA Primer?
Correct Answer
A. RNA Primase
Explanation
RNA primase is the correct answer because it is the enzyme responsible for synthesizing short RNA primers during DNA replication. These primers provide a starting point for DNA polymerases to attach and begin the synthesis of new DNA strands. DNA primase is not a valid option because it does not exist. DNA polymerases are involved in DNA replication but do not produce RNA primers. Therefore, RNA primase is the correct enzyme associated with DNA replication that produces an RNA primer.