Molecular Biology Quiz

Prokaryotes vs Eukaryotes

• Prokaryotes have simultaneous transcription and translation, which is not found in eukaryotes.
• This means that in prokaryotes, the mRNA transcript is being translated into protein while it is still being transcribed from the DNA template.

DNA Replication

• DNA replication is considered semiconservative because it uses the template strands of DNA to synthesize new strands.
• This results in two new DNA molecules, each composed of one old strand (the template) and one new strand synthesized from the template.

Taq Polymerase

• Taq polymerase is used in PCR (Polymerase Chain Reaction) instead of DNA polymerase from E. coli because it is heat-stable.
• This allows it to withstand the high temperatures required for PCR, which would denature and inactivate E. coli DNA polymerase.

Ligase

• Ligase is an enzyme that rejoins segments of DNA.
• It is essential for DNA replication and repair, as it can seal gaps between Okazaki fragments and repair broken DNA strands.

mRNA Processing and DNA Replication

• mRNA processing involves several steps, including splicing, capping, polyadenylation, and transport.
• DNA replication involves the unwinding of DNA, synthesis of new DNA strands, and ligation.

Enzymes in DNA Replication

• DNA ligase is used to join nicks in the DNA strand.
• Helicase is used in the unwinding of DNA.
• Primase is not used to join nicks in the DNA strand, but rather to synthesize RNA primers.
• Endonuclease is not used to join nicks in the DNA strand.

Prokaryotes and Gene Expression

• Transcription, translation, and replication occur in prokaryotes.
• Splicing does not occur in prokaryotes.
• Mutation is necessary for the purpose of evolution.
• Replication is necessary for the survival of the cell.
• Translation is necessary for the synthesis of proteins.
• Transcription is necessary for the synthesis of RNA.

Gene Expression

• Transcription, RNA processing, and translation are all part of gene expression.
• Replication is not part of gene expression.

Constitutive and Inducible Enzymes

• Constitutive enzymes are always expressed and are necessary for the survival of the cell.
• Inducible enzymes are only expressed in response to a specific stimulus or signal.

Generalized and Specialized Transduction

• Generalized transduction involves the transfer of any gene from the donor cell to the recipient cell.
• Specialized transduction involves the transfer of a specific gene from the donor cell to the recipient cell.

Conjugation and DNA Transfer

• An F pilus is essential for plasmid transfer by conjugation.
• DNA transformation involves the transfer of DNA from one cell to another.
• Chromosome transfer by conjugation involves the transfer of the entire chromosome from the donor cell to the recipient cell.

Prokaryotes and Eukaryotes

• Polyribosomes are present in prokaryotes but not eukaryotes.
• Simultaneous transcription and translation occurs in prokaryotes.
• Exons are present in eukaryotes but not prokaryotes.
• Spliceosomes are present in eukaryotes but not prokaryotes.