Question 1

A researcher is using a plasmid vector to clone a gene of interest. Which of the following features is essential for the plasmid to be used as a cloning vector in E. coli?

Accepted Answer

A selectable marker gene such as AmpR

Question 2

Which of the following best describes the function of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It aligns the ribosome with the start codon by base pairing with the 16S rRNA.

Question 3

A DNA sequence is cut with two different restriction enzymes, each producing sticky ends. Which of the following best explains why these sticky ends can be ligated together?

Accepted Answer

The overhanging single-stranded sequences are complementary and can base pair, allowing DNA ligase to seal the nicks.

Question 4

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 5

A mutation changes the codon $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} in an $$mRNA sequence. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 6

During eukaryotic transcription, which of the following is NOT a function of the 5' cap added to mRNA?

Accepted Answer

It serves as a binding site for the Shine-Dalgarno sequence.

Question 7

A cell is observed to have chromosomes aligned at the metaphase plate, each consisting of two sister chromatids. Which stage of the cell cycle is this?

Accepted Answer

Metaphase of mitosis

Question 8

Which of the following best describes the difference between Rho-dependent and Rho-independent termination of transcription in prokaryotes?

Accepted Answer

Rho-dependent termination requires a protein factor that unwinds the RNA-DNA hybrid, while Rho-independent relies on a GC-rich hairpin followed by a poly-U sequence.

Question 9

If a diploid organism has a haploid number $$n = 4$$, how many possible combinations of maternal and paternal chromosomes can be produced in its gametes due to independent assortment?

Accepted Answer

$$2^4 = 16$

Question 10

Which of the following is a function of aminoacyl tRNA synthetase?

Accepted Answer

It attaches the correct amino acid to its corresponding tRNA.

Question 11

A patient is found to have a mutation in the gene encoding the sigma factor in E. coli. Which process is most likely to be directly affected?

Accepted Answer

Recognition of the promoter and initiation of transcription

Question 12

Which of the following best describes the difference between a template strand and a coding strand during transcription?

Accepted Answer

The template strand is used by RNA polymerase to synthesize RNA, while the coding strand has the same sequence as the RNA (except T is replaced by U).

Question 13

Which of the following is a posttranslational modification that can regulate protein function?

Accepted Answer

Phosphorylation

Question 14

A gene contains the following sequence in its coding region: 5'-ATG GAA TGA-3'. What is the amino acid sequence produced (using the standard genetic code)?

Accepted Answer

Met-Glu

Question 15

During meiosis, which two processes are responsible for increasing genetic diversity in gametes?

Accepted Answer

Crossing-over and independent assortment

Question 16

A mutation in a gene changes a codon from $$	ext{GAA} ($$glutamic acid) to $$	ext{GAG} ($$also glutamic acid). What type of mutation is this?

Accepted Answer

Silent (synonymous) mutation

Question 17

Which of the following statements about the differences between prokaryotic and eukaryotic gene expression is correct?

Accepted Answer

In eukaryotes, transcription and translation are separated by the nuclear envelope, while in prokaryotes they are coupled.

Question 18

A cell is observed to have homologous chromosomes paired and crossing over occurring. Which stage of meiosis is this?

Accepted Answer

Prophase I

Question 19

Which of the following best describes the function of the spliceosome?

Accepted Answer

It removes introns from pre-mRNA and joins exons together.

Question 20

A patient has a genetic disorder caused by a frameshift mutation. Which of the following is the most likely molecular consequence?

Accepted Answer

Alteration of the reading frame, resulting in a completely different amino acid sequence downstream of the mutation.

Genetics Exam 2 Study Guide: DNA Technology, Transcription & Translation, and Cell Division

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