Untitled Quiz

What are the four general characteristics of genetic materials?

What is the central dogma of molecular genetics?

What is a mutation?

What is Griffith's transformation?

Avery et al. proved conclusively that DNA is the transforming principle by demonstrating that DNA is the only component that retains the ability to induce transformation after removing other components like proteins and carbohydrates.

Hershey and Chase's experiment used radioactive isotopes P32 and S35 labels to track the protein and DNA components, respectively, of bacteriophage T2 during infection.

Which of the following are indirect evidence to prove DNA as genetic material in eukaryotes?

UV light is most mutagenic at the wavelength of 260nm, and both DNA and RNA absorb UV light most strongly at 260nm, whereas proteins absorb most strongly around 280nm.

Recombinant DNA technology is the strongest evidence that proves DNA is the genetic material.

RNA can act as the genetic material in viruses, such as Tobacco Mosaic Virus (TMV), where the virus's RNA carries the genetic information for replication.

Match the following terms related to DNA structure with their descriptions:

The two strands of DNA in a double helix are parallel, meaning they run in the same direction.

Adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C) through hydrogen bonds, forming the bases of DNA.

Which of the following describes the Watson-Crick model of DNA structure?

The arrangement of sugars and bases along the axis in the Watson-Crick model, where hydrophobic bases are stacked inside and hydrophilic sugar-phosphate backbones are on the outside, contributes to the stability of DNA.

How is DNA denatured?

A melting profile of DNA shows the increase in UV absorption versus temperature, and the melting temperature (Tm) is the midpoint of this profile, where 50 percent of the DNA strands are unwound.

What are some applications of molecular hybridization?

Gel electrophoresis separates molecules based on their size and charge, with smaller molecules migrating faster through the gel than larger molecules.

Which of the following is NOT a mode of DNA replication?

The Meselson-Stahl experiment used the heavy isotope of nitrogen, N15, to demonstrate that DNA replication is semiconservative.

In eukaryotes, DNA replication occurs simultaneously at multiple replication origins, with each origin forming a replication bubble.

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously in Okazaki fragments.

Which enzyme is primarily responsible for DNA synthesis during replication in bacteria?

The sliding DNA clamp is a ring-shaped structure that encircles the DNA and prevents the core enzyme from dissociating from the template during replication.

What is a replisome?

What is the origin of replication in E. coli called?

DNA polymerase I is responsible for removing RNA primers and filling the gaps left after their removal during DNA replication in bacteria.

DNA polymerase III can initiate DNA synthesis de novo, meaning it can start synthesis without a primer.

Proofreading during DNA replication corrects errors by the 3' to 5' exonuclease activity of DNA polymerase.

What is the role of DNA gyrase during DNA replication?

The lagging strand is synthesized in the same direction as the leading strand.

DNA ligase joins Okazaki fragments together on the lagging strand.

Eukaryotic DNA replication shares many similarities with bacterial DNA replication, including the use of a single origin of replication, bidirectional replication, and the presence of leading and lagging strands.

Eukaryotic DNA replication occurs in the cytoplasm.

Eukaryotic DNA replication origins are known as Autonomously Replicating Sequences (ARSs) and are typically 120 base pairs long.

The pre-RC, or prereplication complex, assembles at replication origins during the G1 phase of the cell cycle, marking them as potential sites for replication.

DNA polymerase α is responsible for synthesizing both the leading and lagging strands during eukaryotic DNA replication.

Eukaryotic DNA polymerase γ is responsible for replicating mitochondrial DNA.

Telomeres are repetitive DNA sequences found at the ends of linear eukaryotic chromosomes that help prevent chromosome degradation and fusion.

The 3'-end of the telomere extends as an overhang, forming a single-stranded tail that can loop back on itself, creating a t-loop structure.

Telomerase is an enzyme that extends the 3'-end of the telomere, preventing chromosome shortening during replication.

Homologous recombination is a reciprocal genetic exchange between two DNA molecules, resulting in the creation of new combinations of genetic material.

Gene conversion is a nonreciprocal exchange of genetic information between two DNA molecules, where one molecule inherits a copy of a gene from the other molecule.

The genetic code is a triplet code, meaning that each amino acid is encoded by a sequence of three nucleotides.

The genetic code is unambiguous, meaning that each codon specifies only one amino acid.

The genetic code is degenerate, meaning that multiple codons can specify the same amino acid.

The wobble hypothesis explains the flexibility in base pairing at the third position of the codon, allowing a single tRNA to recognize multiple codons.

AUG is the initiator codon, specifying methionine, while UAG, UAA, and UGA are termination codons.

A nonsense mutation occurs when a codon is changed to a termination codon, resulting in the premature termination of protein synthesis.

Overlapping genes occur when a single mRNA molecule can be translated into multiple proteins by using different reading frames.

Transcription is the process of copying the genetic information from DNA to RNA, acting as the first step in gene expression.

RNA polymerase is the enzyme responsible for synthesizing RNA from a DNA template, requiring a primer to initiate synthesis.

Promoters are DNA sequences that signal the location of genes and serve as binding sites for RNA polymerase, initiating transcription.

The sigma subunit (σ subunit) of RNA polymerase recognizes specific promoter sequences, initiating transcription in bacteria.

Transcription in prokaryotes is typically polycistronic, meaning that a single mRNA molecule can encode multiple proteins.

Transcription in eukaryotes is typically monocistronic, meaning that each mRNA molecule encodes only one protein.

RNA splicing is a process that removes introns, noncoding sequences within a eukaryotic pre-mRNA, to produce a mature mRNA.

RNA editing refers to the process of altering the nucleotide sequence of a pre-mRNA prior to translation, resulting in changes to the protein product.