AP Biology Unit 6: Gene Expression and Regulation Practice Exam

1. Which of the following statements best describes the results observed after one generation of replication (Generation 1)?

2. The results from Generation 2 are critical for distinguishing between semiconservative and dispersive replication models. How do the results shown for Generation 2 support the semiconservative model?

3. During the synthesis of new DNA strands in this experiment, which enzyme is primarily responsible for adding the $^{14}$N-containing nucleotides to the growing strands, using the $^{15}$N strands as a template?

4. Based on the diagram, which of the following is a key difference between the primary RNA transcript and the mature mRNA?

5. The process of removing introns and joining exons is called splicing. Which of the following best explains a primary consequence of the alternative splicing of a primary transcript?

6. The diagram shows three major types of RNA molecules are involved in the overall process of protein synthesis. Which of the following correctly pairs an RNA type with its primary function?

7. Based on the diagram, what is the direct role of lactose in the regulation of the lac operon?

8. A mutation occurs in the operator region of the lac operon that prevents the repressor protein from binding to it. Which of the following is the most likely claim regarding the effect of this mutation?

9. The regulation of the lac operon is a classic example of an inducible system. This means that the operon is:

10. Using the provided codon chart, what is the amino acid sequence that would be translated from this mRNA sequence?

11. A point mutation occurs, changing the third codon from UCA to UAA. The claim is that this mutation will result in a nonfunctional protein. Which of the following statements provides the best evidence to support this claim?

12. Imagine a different point mutation changes the second codon from GGC to GGU. A student claims this is a neutral mutation. What evidence from the codon chart supports this claim?

13. Which of the following statements accurately describes the separation of DNA fragments shown in the gel?

14. Based on the evidence presented in the gel, which of the following is the most valid claim?

15. The amount of DNA collected from the crime scene was very small. To obtain enough DNA to be visible on the gel, investigators first needed to amplify the specific DNA regions of interest. Which of the following laboratory techniques is best suited for this purpose?

16. Which of the following correctly compares the organization of genetic material in prokaryotes and eukaryotes?

17. The structure of the DNA double helix is stabilized by hydrogen bonds between the nitrogenous bases. Which of the following represents a correct and stable base pairing in DNA?

18. DNA replication involves synthesizing a leading strand continuously and a lagging strand discontinuously in short segments called Okazaki fragments. The enzyme DNA ligase is crucial for the completion of the lagging strand because it:

19. The process of translation requires the conversion of information from the language of nucleic acids to the language of proteins. What is the specific function of transfer RNA (tRNA) in this process?

20. In eukaryotic cells, transcription and translation are spatially and temporally separated. Where does translation primarily occur?

21. Retroviruses, such as HIV, have an RNA genome. They violate the typical central dogma of molecular biology. Which scientific question became relevant upon the discovery of retroviruses?

22. Epigenetic modifications are changes that affect gene expression without altering the DNA sequence itself. Which of the following is an example of an epigenetic mechanism?

23. A muscle cell and a nerve cell in the same person have the same set of genes, but they have very different structures and functions. Which of the following claims best accounts for this difference?

24. A mutation involving the insertion of a single nucleotide pair in the middle of a gene's coding sequence is more likely to be deleterious than a substitution of one nucleotide for another because the insertion will:

25. A researcher wants to produce a human protein, such as insulin, in large quantities using bacteria. To do this, they must insert the human gene for insulin into bacterial plasmids. Which of the following scientific questions is most relevant to the initial step of this genetic engineering procedure?