Transcription, Translation, Mitosis, and Meiosis Review

Exam 3 Practice Questions – Answers

Transcription Review

  1. Transcription in Eukaryotes

    • Requires several elements in addition to RNA polymerase.

      • Correct Answer: D) several transcription factors (TFs).

      • Transcription factors are proteins that bind to specific DNA sequences, influencing the transcription of genetic information.

  2. Termination of Transcription in Prokaryotes

    • Describes how transcription is stopped in prokaryotic cells.

      • Correct Answer: B) RNA polymerase transcribes through the terminator sequence, causing the polymerase to separate from the DNA and release the transcript.

      • This is a key feature of prokaryotic transcription where the terminator signals the end of transcription.

  3. Direction of RNA Polymerase Movement

    • Given an unwound double-stranded DNA template strand.

      • Correct Answer: A) 3' → 5' along the template strand.

      • RNA polymerase moves along the template strand in a direction opposite to that of the RNA synthesis direction, which is 5' → 3'.

  4. Location of the Promoter in Transcription

    • Where is the promoter located concerning the template strand?

      • Correct Answer: C) to the left of the template strand.

      • The promoter is upstream of the transcription start site and is essential for the initiation of transcription.

  5. Components in mRNA in the Cytosol

    • Analyzing a eukaryotic transcript model.

      • Correct Answer: C) 5' UTR E1 E2 E3 E4 UTR 3'.

      • Exons (E) represent the coding sequences that are spliced together to form the mature mRNA, along with the 5' and 3' UTRs (Untranslated Regions).

Translation

  1. Protein Synthesis in Prokaryotes

    • Understanding how translation differs between prokaryotes and eukaryotes.

      • Correct Answer: B) Translation can begin while transcription is still in progress.

      • In prokaryotes, both processes occur simultaneously due to the lack of a nucleus.

  2. Component Not Directly Involved in Translation

    • Identifying which element does not play a direct role in the translation process.

      • Correct Answer: B) DNA.

      • During translation, mRNA, tRNA, and ribosomes are directly involved while DNA is not directly engaged in the translation process.

  3. Amino Acid Sequence from mRNA Codons

    • Calculate the amino acid sequence based on a provided mRNA codon sequence.

      • Correct Answer: D) met-ser-ser-leu-ser-leu.

      • The given mRNA sequence 5' AUG-UCU-UCG-UUA-UCC-UUG 3' translates to these amino acids.

  4. Nonsense Mutation in Codon Sequence

    • Identifying a mutation that creates a premature stop codon.

      • Correct Answer: B) 5' AUG-UCU-UCG-UAA-UCC-UUG 3'.

      • The UAA codon is a stop codon, leading to a truncated protein.

  5. Missense Mutation in Codon Sequence

    • Identifying a mutation that results in a different amino acid.

      • Correct Answer: A) 5' AUG-UCU-UCG-UUA-UCA-UUG 3'.

      • The UCA codon changes the amino acid sequence resulting in a different protein product.

  6. Silent Mutation in Codon Sequence

    • Identifying a mutation that does not change the amino acid.

      • Correct Answer: A) 5' AUG-UCU-UCG-UUA-UCA-UUG 3'.

      • The silent mutation results in the same amino acid being produced, hence, there is no effect on the protein.

Mitosis and Meiosis

  1. Chromosomal Condition at Prometaphase of Mitosis

    • Assessing which diagram correctly illustrates this phase.

      • Correct Answer: A) B.

      • Prometaphase is characterized by the chromosomes becoming even more condensed and the nuclear envelope breaking down.

  2. Chromosomal Condition at Telophase of Mitosis

    • Identifying the details of one daughter nucleus post-mitosis.

      • Correct Answer: C) D.

      • At telophase, two daughter nuclei begin to form, each with the same number of chromosomes as the original cell.

  3. Function of the Mitotic Spindle

    • What role does the mitotic spindle serve in cell division?

      • Correct Answer: D) separation of sister chromatids.

      • The spindle fibers attach to the centromeres and help segregate sister chromatids during anaphase.

  4. Chromosomal Makeup After Telophase I of Meiosis

    • Determine the chromosomal makeup of daughter cells post-meiosis I.

      • Correct Answer: C) haploid, and the chromosomes are each composed of two chromatids.

      • After meiosis I, each daughter cell contains half the number of chromosomes, each still consisting of two sister chromatids.

  5. Key Event of Meiosis Matching

    • Homologous chromosomes aligned at the spindle equator.

      • Correct Answer: B) II (Metaphase I).

  6. Disjunction of Sister Chromatids

    • Which phase marks the separation of sister chromatids?

      • Correct Answer: A) III (Anaphase I).

      • At this stage, homologous chromosomes separate while sister chromatids remain attached until Anaphase II in meiosis.