Question 1

Which of the following best explains why hydrogen atoms bonded to oxygen or nitrogen can participate in hydrogen bonding, but hydrogen atoms bonded to carbon cannot?

Accepted Answer

Oxygen and nitrogen are more electronegative than carbon, creating a partial positive charge on hydrogen that allows hydrogen bonding.

Question 2

PCR (Polymerase Chain Reaction) is a powerful tool in biotechnology. Which of the following steps is essential for PCR to selectively amplify a specific DNA sequence?

Accepted Answer

Cycling through different temperatures to denature DNA, anneal primers, and extend new strands.

Question 3

A scientist wants to insert a gene into a plasmid vector. Which combination of techniques would most efficiently allow her to cut the gene from one DNA molecule and insert it into the plasmid?

Accepted Answer

Restriction digest followed by ligation.

Question 4

During gel electrophoresis, why do smaller DNA fragments travel farther through the agarose gel than larger fragments?

Accepted Answer

Smaller fragments encounter less resistance moving through the gel matrix.

Question 5

Which of the following best describes the main advantage of sexual reproduction over asexual reproduction in changing environments?

Accepted Answer

Sexual reproduction increases genetic diversity, allowing populations to adapt to environmental changes.

Question 6

In eukaryotic cells, which of the following modifications occurs to pre-mRNA before it is exported to the cytoplasm?

Accepted Answer

Addition of a 5’ cap, removal of introns, and addition of a 3’ poly-A tail.

Question 7

A patient is treated with CRISPR to correct a genetic disease. The therapy relies on homology-directed repair. During which phase of the cell cycle is this repair most likely to occur, and why?

Accepted Answer

G2 phase, because a homologous chromosome is available as a template for repair.

Question 8

Which of the following statements about DNA gel electrophoresis is correct?

Accepted Answer

DNA moves toward the positive electrode due to its negative charge.

Question 9

A researcher uses PCR to detect a viral infection in a patient sample. Which of the following best explains why PCR is effective for this purpose?

Accepted Answer

PCR can amplify even a single copy of viral DNA to detectable levels.

Question 10

Which of the following is a direct consequence if mRNAs that should be rapidly degraded persist for too long in a cell?

Accepted Answer

Proteins may be overproduced, potentially leading to diseases such as cancer.

Question 11

A pedigree shows a genetic condition appearing in every generation, affecting both males and females, and being transmitted from father to child. Which inheritance pattern is most likely?

Accepted Answer

Autosomal dominant

Question 12

Which of the following best describes the flow of genetic information in cells?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 13

Which of the following is a key reason why CRISPR is not easily used to cure cancer compared to single-gene diseases?

Accepted Answer

Curing cancer would require correcting mutations in all cancer cells, not just a fraction.

Question 14

Which of the following best explains why bacteria methylate their own DNA in the context of restriction enzymes?

Accepted Answer

To protect their own DNA from being cut by their restriction enzymes.

Question 15

A scientist is using a restriction enzyme that creates sticky ends. What is the main advantage of sticky ends in molecular cloning?

Accepted Answer

Sticky ends allow for easier and more specific ligation of DNA fragments.

Question 16

Which of the following is true about the mutation rate in asexual versus sexual reproduction?

Accepted Answer

Sexual reproduction has a higher mutation rate and shuffles genomes, increasing diversity.

Question 17

Which of the following best describes the role of primers in PCR?

Accepted Answer

Primers provide a starting point for DNA polymerase to synthesize new DNA strands.

Question 18

Which of the following is a real-world application of DNA sequencing technology?

Accepted Answer

Identifying genetic mutations responsible for inherited diseases.

Question 19

If a cell repairs a CRISPR-induced double-strand break using non-homologous end joining (NHEJ), what is the most likely outcome?

Accepted Answer

The gene at the break site is often inactivated due to small insertions or deletions.

Question 20

Which of the following best describes epistasis in genetic pathways?

Accepted Answer

Epistasis occurs when one gene's product affects the expression of another gene in a signaling cascade.

Overall Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards