Molecular Biology Quiz: RNA and DNA Processes

<p>Addition of phosphate groups to ribose residues (D)</p> Signup and view all the answers

<p>In the nucleolus (D)</p> Signup and view all the answers

<p>DNA polymerases α, δ, and ε (C)</p> Signup and view all the answers

<p>They synthesize DNA only in the 5' to 3' direction. (D)</p> Signup and view all the answers

<p>Initiator proteins recognizing specific nucleotide sequences (B)</p> Signup and view all the answers

<p>One single origin of replication (A)</p> Signup and view all the answers

<p>Eukaryotes need multiple origins to replicate long chromosomes. (C)</p> Signup and view all the answers

<p>It would potentially take several weeks to replicate. (D)</p> Signup and view all the answers

<p>Replication complex or replisome (A)</p> Signup and view all the answers

<p>It unwinds the DNA strands. (D)</p> Signup and view all the answers

<p>RNApolIII (A)</p> Signup and view all the answers

<p>200 (B)</p> Signup and view all the answers

<p>Chromosome 1 (B)</p> Signup and view all the answers

<p>Fibrillar center, dense fibrillar component, granular component (C)</p> Signup and view all the answers

<p>Metabolic activity of the cell (C)</p> Signup and view all the answers

<p>It is processed into the functional forms of 5.8S, 18S, and 28S rRNAs. (B)</p> Signup and view all the answers

<p>High number of RNA polymerase molecules (A)</p> Signup and view all the answers

<p>Granular component (C)</p> Signup and view all the answers

<p>To inhibit translation or stimulate mRNA degradation (B)</p> Signup and view all the answers

<p>Up to 100 (B)</p> Signup and view all the answers

<p>Long non-coding RNA (lncRNA) (A)</p> Signup and view all the answers

<p>To act as communication channels for selective exchange of molecules (C)</p> Signup and view all the answers

<p>It consists of repetitive DNA sequences (D)</p> Signup and view all the answers

<p>Nuclear lamina (D)</p> Signup and view all the answers

<p>AT-rich sequences are less dense than GC-rich sequences (C)</p> Signup and view all the answers

<p>To act as a selective barrier regulating molecule traffic (B)</p> Signup and view all the answers

<p>They cause retention in the cytoplasm. (C)</p> Signup and view all the answers

<p>Rich in Lys and Arg. (A)</p> Signup and view all the answers

<p>Importins and Ran proteins. (C)</p> Signup and view all the answers

<p>It releases the cargo protein. (D)</p> Signup and view all the answers

<p>Hydrolyzes GTP in Ran to GDP. (C)</p> Signup and view all the answers

<p>Bipartite sequence separated by a short sequence. (A)</p> Signup and view all the answers

<p>By binding to cytoplasmic filaments of the nuclear pore complex. (C)</p> Signup and view all the answers

<p>High concentration of Ran/GTP in the nucleus. (A)</p> Signup and view all the answers

<p>They catalyze the unwinding of parental DNA. (D)</p> Signup and view all the answers

<p>By creating transient breaks in the DNA strands. (B)</p> Signup and view all the answers

<p>It ensures high fidelity for cell reproduction. (A)</p> Signup and view all the answers

<p>They cleave incorrect bases from the growing DNA strand. (C)</p> Signup and view all the answers

<p>To stabilize uncoiled DNA strands. (B)</p> Signup and view all the answers

<p>It can synthesize oligonucleotides with telomeric sequences. (C)</p> Signup and view all the answers

<p>Through double reading activity. (D)</p> Signup and view all the answers

<p>It cleaves RNA primers post-replication. (C)</p> Signup and view all the answers

Enzymes that unwind the double helix of DNA during replication, separating the two strands. They use the energy from ATP hydrolysis to break the hydrogen bonds between the bases.

Proteins that bind to single-stranded DNA, preventing it from re-annealing and keeping it available for replication.

Enzymes that relieve the torsional stress caused by DNA unwinding during replication. They cut and re-ligate DNA strands to allow for rotation.

The process of copying DNA, resulting in two identical DNA molecules. It involves unwinding the double helix, separating the strands, and using each strand as a template to synthesize a new complementary strand.

A specialized DNA polymerase that adds repetitive sequences to the ends of chromosomes (telomeres) to protect them from degradation during replication.

The accuracy of DNA replication, measured as the number of incorrect bases incorporated per nucleotide.

The ability of DNA polymerase to proofread its own work and remove incorrect bases, ensuring accurate replication.

A process where DNA polymerase checks the newly added base against the template strand, correcting any mismatches before moving on.

Small, non-coding RNA molecules involved in gene regulation. They bind to a protein complex called RISC to target and repress specific mRNAs.

Long, non-coding RNA molecules (over 200 nucleotides) with diverse roles in gene regulation, including X-chromosome inactivation in females.

A double-layered membrane that encloses the nucleus, providing a barrier between the nucleus and cytoplasm.

Complex protein structures embedded within the nuclear envelope, serving as the only communication channels between the nucleus and cytoplasm, allowing controlled transport of molecules.

A protein meshwork lining the inner surface of the nuclear envelope, providing structural support and anchoring DNA.

Repeating sequences of DNA that are not transcribed and do not contain functional genetic information, but are important for chromosome structure.

Tandemly repeated short DNA sequences (1-500 nt) that are not transcribed and contribute to chromosome structure.

DNA sequences enriched in A and T bases, which are less dense than GC-rich sequences, thus forming a separate band when separated by density gradient centrifugation.

DNA polymerases are enzymes that synthesize new DNA strands during replication, with two essential properties: 1. They can only add nucleotides in the 5' to 3' direction. 2. They require a pre-existing primer strand to initiate synthesis. They cannot start a new strand from scratch.

The specific DNA sequence where DNA replication begins. It serves as the starting point for unwinding and separating the two DNA strands, creating two replication forks.

Initiator proteins bind to specific sequences at the origin of replication, initiating the unwinding process.

A complex of proteins and enzymes that participate in DNA replication. It coordinates the process, including unwinding DNA, synthesizing new strands, and proofreading for errors.

In prokaryotes, replication starts from a single origin and proceeds bidirectionally along the circular chromosome.

In eukaryotes, multiple origins of replication are required to efficiently replicate the larger and more complex chromosomes. Each origin initiates independent replication bubbles, speeding up the entire process.

A short sequence of amino acids within a protein that acts as a signal for the protein to be transported into the nucleus.

A protein that binds to the NLS of a cargo protein and facilitates its transport from the cytoplasm to the nucleus.

A GTP-binding protein that plays a crucial role in nuclear transport by regulating the directionality of import and export.

The importin-cargo complex binds to the proteins of the cytoplasmic filaments of the nuclear pore complex and is transported through the pore.

The process by which a protein with a NLS is recognized by importin and then transported through the nuclear pore complex into the nucleus.

The importin-Ran/GTP complex is re-exported through the nuclear pore.

A GTPase activating protein (Ran-GAP) associated with cytoplasmic filaments hydrolyzes GTP in Ran to GDP, releasing importin.

The process where the Ran protein cycles between a GTP-bound state and a GDP-bound state, controlling the directionality of nuclear transport.

rRNA processing involves modifying the pre-rRNA molecule by adding methyl groups to certain ribose sugars. Conversion of uridine to pseudouridine. These modifications are crucial for proper rRNA function.

snoRNPs, composed of snoRNAs and proteins, play a crucial role in pre-rRNA processing by guiding enzymes to specific locations on the pre-rRNA molecule for modification.

Ribosome assembly involves the association of pre-rRNA with ribosomal proteins and 5S rRNA. This assembly takes place in the nucleolus.

Ribosomal proteins, synthesized outside the nucleolus by RNA polymerase II and translated in the cytoplasm, are transported to the nucleolus where they participate in ribosome assembly.

Genes for 5S rRNA are transcribed by RNA polymerase III outside the nucleolus and transported to the nucleolus where they assemble along with pre-rRNA and ribosomal proteins.

The process of creating ribosomal RNA (rRNA) molecules.

A large precursor molecule that contains all three rRNA components (28S, 5.8S, and 18S) before it is processed.

The site within the nucleus where rRNA is transcribed and ribosomes are assembled.

Regions on chromosomes that contain the genes for 5.8S, 18S, and 28S rRNAs. These regions are essential for nucleolus formation.

The enzyme responsible for transcribing 45S pre-rRNA.

The process of converting the 45S pre-rRNA into mature rRNA molecules.

A region within the nucleolus where pre-rRNA is processed.

A region within the nucleolus where ribosomal subunits are assembled.