Unit 6: Gene Expression and Regulation

Based on the mRNA sequence, what is the amino acid sequence of the resulting polypeptide?

During translation, the mRNA codon is read by a complementary

If a point mutation changes the third codon from UAC to UAG, what is the effect on the polypeptide?

If a single nucleotide insertion occurs after the AUG start codon, the most dramatic effect would be

During transcription, which enzyme synthesizes mRNA from a DNA template?

In eukaryotes, the removal of introns from pre-mRNA is carried out by

Alternative splicing allows a single gene to

The lac operon in E. coli is an example of

Which of the following correctly pairs a type of mutation with its description?

Epigenetic modifications such as DNA methylation can affect gene expression by

A researcher uses gel electrophoresis to separate DNA fragments produced by restriction enzyme digestion. The DNA fragments migrate through the gel based on

Which of the following technologies allows scientists to edit specific genes in living organisms?

The redundancy (degeneracy) of the genetic code means that

In the PCR process described, what is the purpose of the 95°C denaturation step?

After 30 cycles of PCR, approximately how many copies of the target DNA would be produced?

Taq polymerase is used in PCR instead of human DNA polymerase because

A DNA strand reads 3'-TACGAATCG-5'. What is the corresponding mRNA sequence?

If a gene contains 900 nucleotides in the coding region (excluding the stop codon), how many amino acids will the resulting polypeptide contain?

RNA interference (RNAi) regulates gene expression by

Which of the following best explains why β-galactosidase is produced at high levels only in condition 2 (lactose-only medium)?

If a mutation in the lac repressor protein prevents it from binding allolactose but does not affect its ability to bind the operator, what would be the expected effect on lac operon expression?

In condition 2, which molecular event directly enables RNA polymerase to achieve maximal transcription of the lac operon?

How many EcoRI recognition sites are present in the plasmid?

If the student forgot to add loading dye to the samples before loading them onto the gel, which of the following would most likely result?

If a different restriction enzyme cuts the same circular plasmid into two fragments of 4,500 bp and 1,500 bp, how many recognition sites does this enzyme have in the plasmid?

A linear DNA molecule is 10,000 bp long. It is digested with a restriction enzyme that has recognition sites at positions 2,500 bp and 7,000 bp from one end. How many fragments will be produced?

DNA methylation of CpG islands in a gene's promoter region typically results in which of the following?

Alternative splicing of pre-mRNA allows a single gene to produce:

A researcher introduces a small interfering RNA (siRNA) complementary to the mRNA of gene X into a cell. What is the most likely immediate effect?

In eukaryotic gene regulation, enhancer sequences can stimulate transcription of a gene located thousands of base pairs away. Which mechanism best explains how enhancers function over such large distances?

Histone acetylation is an epigenetic modification generally associated with:

A point mutation changes a codon in an mRNA from UAC (tyrosine) to UAG. This mutation is best classified as a:

The CRISPR-Cas9 system enables precise genome editing by:

A frameshift mutation is most likely to result from:

The trp operon in *E. coli* operates as a repressible system. When intracellular tryptophan levels are high, what occurs?

All cells in a multicellular organism contain the same genome, yet a neuron and a liver cell have very different structures and functions. This difference is primarily due to:

A segment of template (non-coding) DNA has the sequence 3'-TACGGATTC-5'. This segment is transcribed and translated. Assuming the entire mRNA is translated, how many amino acids will the resulting polypeptide contain?