DNA Replication Quiz

Nucleic acids are large molecules made up of simpler building blocks called nucleotides. Nucleotides consist of three components:

• A 5-carbon sugar: deoxyribose (in DNA) or ribose (in RNA)
• A nitrogenous base: adenine (A), guanine (G), cytosine (C), thymine (T) in DNA, or uracil (U) in RNA
• A phosphate group: a molecule containing phosphorus and oxygen.

The combination of a sugar and a nitrogenous base is called a nucleoside. It's the basic unit before the phosphate group is added.

Adenine (A) always pairs with thymine (T) in DNA, and guanine (G) always pairs with cytosine (C).

The process by which DNA replicates itself, creating identical copies. This is essential for cell division and passing genetic information.

DNA is a double-stranded helix, each strand made of a chain of nucleotides. The two strands are held together by hydrogen bonds between the bases.

RNA is a single-stranded nucleic acid that plays a crucial role in protein synthesis. It serves as a messenger between DNA and the ribosomes.

RNA has uracil (U) instead of thymine (T) as a nitrogenous base.

The process by which genetic information coded in DNA is used to create proteins.

Two negatively charged atoms that share a hydrogen atom, forming a weak bond.

The specific pairing of nitrogenous bases in DNA: Adenine (A) always pairs with Thymine (T), and Guanine (G) always pairs with Cytosine (C).

The arrangement of two DNA strands, running in opposite directions, connected by hydrogen bonds between the bases.

The backbone of DNA, formed by alternating sugar (deoxyribose) and phosphate groups.

The directionality of a DNA strand, determined by the 5' phosphate group at one end and the 3' hydroxyl group at the other end.

The most common form of DNA found in living organisms, characterized by a right-handed helix.

A less common form of DNA that exists in low water environments, also characterized by a right-handed helix.

The rarest form of DNA, characterized by a left-handed helix and found in DNA rich in guanine and cytosine.

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T) are the four nitrogenous bases that make up DNA. They are essential for storing and transmitting genetic information.

The structure of DNA resembles a twisted ladder, with two strands of nucleotides linked together by hydrogen bonds. The bases A and T pair together, while C and G pair together.

The structure of RNA is typically single-stranded, unlike DNA. RNA uses the same bases as DNA except for uracil (U) which replaces thymine (T).

Nucleic acids are complex biomolecules that play essential roles in living organisms. They store and transmit genetic information, and they are crucial for protein synthesis. The two main types of nucleic acids are DNA and RNA.

During DNA replication, the two strands of the parental DNA molecule separate. Each strand serves as a template for the synthesis of a new complementary strand. This results in two identical DNA molecules, each containing one original strand and one newly synthesized strand.

The origin of replication (OR) is the specific location on a DNA molecule where replication begins. This is where the DNA strands separate and replication proceeds in both directions.

In prokaryotes, there is a single origin of replication (OR) on their circular DNA. This is where replication initiates.

Eukaryotes have multiple origins of replication (ORs) scattered along their linear DNA. This is because eukaryotic DNA is much longer and needs multiple starting points for replication.

Replication bubbles are formed when DNA strands separate at the origin of replication. These bubbles expand as replication proceeds in both directions.

The replication fork is the Y-shaped structure formed during DNA replication. It represents the region where the parental DNA strands are being unwound and new strands are being synthesized.

In eukaryotes, replication occurs in three waves. First, highly active regions (chromatin) are replicated, followed by less active regions (euchromatin), and finally, inactive DNA (heterochromatin) is replicated last.

Enzymes responsible for synthesizing new DNA strands during replication. They work in a 5' to 3' direction, adding nucleotides to the growing strand.

DNA replication is the process of copying a DNA molecule to create two identical copies. It occurs in both directions from the origin of replication, making it bidirectional.

The point where the double helix is unwound during replication, forming a Y-shaped structure. It's where the new DNA strands are synthesized.

The ability of some DNA polymerases to correct errors made during replication by removing nucleotides in the 3' to 5' direction.

DNA synthesis always occurs in the 5' to 3' direction, meaning nucleotides are added to the free 3' end of the growing strand.

DNA replication proceeds in a 5' to 3' direction, creating two new strands from a single template. One strand is synthesized continuously as the replication fork advances (leading strand), while the other is synthesized in short fragments (Okazaki fragments) due to the antiparallel nature of DNA (lagging strand).

DNA replication is called semi-discontinuous because one strand is synthesized continuously, while the other is synthesized in short fragments.

In prokaryotes, DNA replication starts at a specific origin of replication and proceeds bidirectionally, meaning it moves in both directions from the origin. The process involves helicase unwinding the DNA, single-strand binding proteins stabilizing the separated strands, primase laying down RNA primers, and DNA polymerase III adding nucleotides to the growing strand.

DNA polymerases are enzymes that catalyze the addition of nucleotides to a growing DNA strand, always in the 5' to 3' direction. Prokaryotes typically have multiple DNA polymerases, each with specific functions. DNA polymerase I is involved in removing RNA primers and filling in the gaps, while DNA polymerase III is responsible for the main elongation process.

Prokaryotic DNA replication requires several proteins in addition to DNA polymerases. Helicase unwinds the DNA double helix, single-strand binding proteins (SSBs) stabilize the separated strands by preventing them from re-annealing, primase synthesizes short RNA primers to initiate DNA synthesis, and topoisomerases relieve the torsional stress caused by unwinding.

DNA replication requires a DNA template, which serves as a model for the new strand, 4 dNTPs (dATP, dTTP, dGTP, dCTP) as building blocks, magnesium ions to stabilize DNA and proteins, and a primer with a free 3' OH end to begin the synthesis.

The newly synthesized DNA strand is complementary to the template strand. Due to the antiparallel nature of DNA, one of the new strands is synthesized continuously (leading strand), while the other is synthesized in short fragments (lagging strand).

DNA replication ensures that each daughter cell receives a complete copy of the genetic information from the parent cell. This is essential for cell division and inheritance.