ap bio test 4-10

Which of the following best describes the most likely impact on an individual produced from fertilization between one of the daughter cells shown and a normal gamete?

Because nondisjunction occurred in anaphase I, all gametes will have an abnormal chromosome number and the individual will likely exhibit phenotypic evidence of the nondisjunction event.

Which of the following sets of graphs best summarizes the results of the experiments?

Control (no inhibitor): straight diagonal experiment (with inhibitor): dotted straight diagonal, solid constant

Which of the following correctly explains where DNAreplication will begin on the strand oriented 5'→3', reading from left to right?

DNA replication will be initiated immediately to the left of the RNA, since DNA polymerase requires an RNA primer.

Figure 1. Model of a relationship between a transcription factor and selected genes Which of the following scientific claims is most consistent with the information provided in Figure 1 ?

Different genes may be regulated by the same transcription factor.

Histone methyltransferases are a class of enzymes that methylate certain amino acid sequences in histone proteins. A research team found that transcription of gene R� decreases when histone methyltransferase activity is inhibited. Which scientific claim is most consistent with these findings?

Histone methylation opens up chromatin at gene R� so transcription factors can bind to DNA more easily.

Figure 1. Process occurring in a cell Which of the following correctly explains the process shown in Figure 1 ?

Initiation of transcription is occurring because a strand of RNA is being produced from a DNA template strand.

The claim that gene regulation results in differential gene expression and influences cellular products (albumin or crystalline) is best supported by evidence in which of the following statements?

Liver cells possess transcriptional activators that are different from those of lens cells.

Which of the following statements best explains the pattern seen on the gel with regard to the size and charge of molecules A and B?

Molecules A and B are negatively charged, and molecule A is smaller than molecule B.

Which of the following best explains the distribution of lactase persistence in the areas shown in Figure 1 ?

Mutations conferring lactase persistence likely arose independently in different geographic areas and offered a selective advantage.

Figure 1. Model of a process involving nucleic acids Which of the following best explains what process is represented in Figure 1 ?

New DNA strands are being synthesized in the 5' to 3' direction from their DNA templates.

Which of the following statements best explains the structure and importance of plasmids to prokaryotes?

Plasmids are circular, double-stranded DNA molecules that provide genes that may aid in survival of the prokaryotic cell.

Genetic engineering techniques can be used when analyzing and manipulating DNA and RNA. Scientists used gel electrophoresis to study transcription of gene L� and discovered that mRNA strands of three different lengths are consistently produced. Which of the following explanations best accounts for this experimental result?

Pre-mRNA of gene L� is subject to alternative splicing, so three mRNA sequences are possible.

Which of the following statements best explains the data set?

Since the %A and the %T are approximately the same in each sample, adenine and thymine molecules must pair up in a double-stranded DNAmolecule.

Which of the following best describes the type of mutation shown in Figure 1 that leads to sickle-cell anemia?

Substitution

Which of the following best predicts the most direct effect of exposing prokaryotic cells to streptomycin?

Synthesis of polypeptides will be inhibited.

Which of the following best explains how bacteria can be genetically engineered to produce a desired antigen?

The gene coding for the antigen can be inserted into plasmids that can be used to transform the bacteria.

Which of the following statements best explains how the genes for antibiotic resistance can be transmitted between bacteria without the exchange of bacterial chromosomal DNA?

The genes for antibiotic resistance are located on a plasmid that can be passed to neighboring bacteria.

Based on the information in Table 1, which of the following best predicts a key difference in prokaryotes and eukaryotes with regard to transcription and translation?

The two processes will occur simultaneously in prokaryotes but not eukaryotes.

Researchers claim that bacteria that live in environments heavily contaminated with arsenic are more efficient at processing arsenic into arsenite and removing this toxin from their cells. Justify this claim based on the evidence shown in Figure 1.

There are multiple operons controlling the production of proteins that process and remove arsenite from cells in both H. arsenicoxydans and O. tritici. In contrast, E. coli has only one operon devoted to arsenic removal.

Which is a scientific claim that is consistent with the information provided and Figure 1 ?

When bound to the operator, the repressor protein prevents lactose metabolism in E. coli.

Use the response models shown in Figures 1 and 2 to justify the claim that phytochromes regulate the transcription of genes leading to the production of certain cellular proteins.

When inactive phytochrome Pr is activated by red light to become phytochrome Pfr, it is transported into the nucleus where it binds to the transcription factor PIF3 at the promoter. This stimulates transcription, ultimately leading to protein production. Far-red light inactivates the phytochrome, which will turn transcription off by not binding to PIF3.

The features of this model provide evidence for which explanation of why all growing strands are synthesized in a 5′ to 3′ direction?

carbon of the dTMP, forms a covalent bond with the oxygen atom attached to the 3′ carbon of the growing strand.